1.

Standards

The aim of standardization is to reduce technical and commercial differences in products, define and unify right concepts and ways of expressions and to find right products
and procedures for both parties. Standardization leads to easier global trade and increase of safety and wellfare.

DIN German national standard (Deutsches Institut für Normung). DIN-numbers are still valid for products which do not have ISO- or EN-standard.
ISO International standard (International Standardization Organisation). Many DIN-standard have formed basis for ISO-standards.
DIN ISO German national version of ISO-standard where to many ISO-numbers have been taken unchanged.

EN Euroapean standard (CEN = Comité Européen de Normalisation). Valid ISO-standards have been taken to use unchanged in EN-standards as far
as possible. If EN-standard differs from ISO-standard, product specification is done according to EN-standard.

DIN EN German national version of EN-standard unchanged. According to Euroapean Council’s decision, member countries of Euroapean Union take EN-
standards into use unchanged. Corresponding national standards are cancelled simultaneously. If EN-standard differs from ISO-standard, product
specification is done according to EN-standard.

EN ISO Euroapean version of ISO-standard unchanged. EN- and ISO-numbers are identical, former procedure “ISO-number + 20 000” have not been
valid since 1/95. In exception are the standards that are in the conversation procedure. Product specification is done according to ISO-standard.

DIN EN ISO German national version of EN ISO-standard unchanged.. Product specification is done according to ISO-standard.

SFS Finnish national standard. Applying of International and Euroapean standards as shown above.

In fasteners business the most commonly used in standards areDIN- and ISO-standards. DIN- and ISO-standards differences in product dimensions:

DIN ISO Item Differences

1 2339 Taper pin Usually replaceable. Lenght in DIN-standard do not include pin´s ends.
7 2338 Parallel pin Usually replaceable. Lenght in DIN-standard do not include pin´s ends.
84 1207 Slotted cheese head screw Differences in head dimensions
85 1580 Differences in head dimensions
94 1234 Splint pin -
125 7089 Washer Nominal dimensions based on thread diameter (ISO) , or on hole diameter (DIN). No dimensional differences
126 7090 Washer Nominal dimensions based on thread diameter (ISO) , or on hole diameter (DIN). No dimensional differences
127 - Spring washer -
314 - Wing nut -
315
316
318
417 7435 Slotted grub screw with full Usually replaceable
dog point
427 2342 slotted headless screw with Usually replaceable
chamfered end
433 7092 Washer -
434 - Square washer -
435
436
438 7436 Countersank head rivet No dimensional differences
439 7435 Hexagon nut Usually replaceable
440 7094 Spring washer No dimensional differences
© Ferrometal 08/2015

444 - Eye bolt -

471 - Retaining bolt -
472 - Retaining ring for bore -
551 4766 Slotted grub screw with flat No dimensional differences
point
553 7434 Slotted set screw with cone No dimensional differences
point
555 4034 Hexagon nut Differences in width across flats and in height of the nut. Look DIN-ISO detailed comparison.
558 4018 Hexagon screw No dimensional differences

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 DIN ISO Item Differences
580 3266 Lifting eye bolt No dimensional differences.
601 4016 Hexagon bolt
603 8677 Mushroom head square head bolt -
906 - Pipe plug -
908
910
912 4762 Hexagon socket head screw No dimensional differences
914 4027 Hexagon socket set screw No dimensional differences
916 4029 hexagon socket set screw, cup point No dimensional differences
929 - Hexagon weld nut -
931 4014 Hexagon bolt Differences in width across flats (M10, 12, 14 and 22). Usually replacaple
933 4017 Hexagon head bolt Differences in width across flats (M10, 12, 14 and 22). Usually replacaple
934 4032 Hexagon nut Differences in width across flats and in height of the nut (M10, 12, 14 and 22).
Look DIN-ISO detailed comparison.
935 - Hexagon slotted and castle nut -
938 - Stud -
939
960 8765 Hexagon bolt, metric fine pitch thread -
961 8676 Hexagon screw, metric fine pitch thread -
963 2009 Slotted countersank head screw Differences in head dimensions
964 2010 slotted raised countersank head screw Differences in head dimensions
965 7046 Cross recessed countersank head screw Differences in head dimensions
966 7047 Cross recessed countersank head screw Differences in head dimensions
971 4034 Hexagon nut -
975 - Threaded rod -
976 - Threaded rod -
980 7042 Selflocking hex. nut -
985 10511 selflocking hex. nut
1440 8738 Washer Usually replaceable
1441 8738 Washer -
1481 8752 Spring type straight pin Chamfer in both ends: ISO D<10mm, DIN D<6mm
6325 8734 Parallel pin -
6914 7412 HV Hexagon nut -
6915 7414 HV hexagon nut -
6916 7416 HV washer -
7504 15480 Selfdrilling screw, -
hexagon head
15481 selfdrilling screw,
pan head
15482 Selfdrilling screw,
countersank head
7976 1479 Hexagon head tapping screw Differences in head dimensions
7978 8736 Taper pin with internal thread -
7980 - single coil spring washer -
7981 Cross recessed pan head tapping screw Differences in head dimensions
7982 7050 Cross recessed countersank head Differences in head dimensions. Countersank head: ISO 90º, DIN 80º
tapping screw
© Ferrometal 08/2015

7983 7051 Cross recessed raised countersank head Differences in head dimensions. Countersank head: ISO 90º, DIN 80º
tapping screw
7985 7045 Cross recessed raised countersank head Differences in head dimensions.
screw
9021 7093 Spring washer Nominal dimensions based on thread diameter (ISO), or on hole diameter (DIN).
Usually replaceable.

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 DIN-ISO standards detailed comparison
Across flats in hexagon head screws/nuts. (DIN 439, 557, 562, 917, 931, 933, 934, 935, 979, 980, 982, 985, 986, 1587, 6330, 6331, 6923).

Width across Nuts height min-max

flats
d DIN ISO DIN ISO DIN 934 ISO
555 4034 4032
8673
M1 2,5 - - 0,55 - 0,8 - -
M 1,2 3 - - 0,75-1 -
M 1,4 3 - - 0,95-1,2 -
M 1,6 3,2 - - 1,05-1,3 1,05-1,3
M2 4 - - 1,35-1,6 1,35-1,6
M 2,5 5 - - 1,75-2 1,75-2
M3 5,5 - - 2,15-2,4 2,15-2,4
M 3,5 6 - - 2,55-2,8 2,55-2,8
M4 7 - - 2,9-3,2 2,9-3,2
M5 8 3,4-4,6 4,4-5,6 3,7-4 4,4-4,7
M6 10 4,4-5,6 4,6-6,1 4,7-5 4,9-5,2
M7 11 - - 5,2-5,5 -
M8 13 5,75-7,25 6,4-7,9 6,14-6,5 6,44-6,7
M 10 17 16 7,25-8,75 8-9,5 7,64-8 8,04-8,4
M 12 19 18 9,25-10,75 10,4-12,2 9,64-10 10,37-10,8
M 14 22 21 - 12,1-13,9 10,3-11 12,1-12,8
M 16 24 12,1-13,9 14,1-15,9 12,3-13 14,1-14,8
M 18 27 - 15,1-16,9 14,3-15 15,1-15,8
M 20 30 15,1-16,9 16,9-19 14,9-16 16,9-18
M 22 32 34 17,1-18,9 18,1-20,2 16,9-18 18,1-19,4
M 24 36 17,95-20,05 20,2-22,3 17,7-19 20,2-21,5
M 27 41 20,95-23,05 22,6-24,7 20,7-22 22,5-23,8
M 30 46 22,95-25,05 24,3-26,4 22,7-24 24,3-25,6
M 33 50 24,95-27,05 27,4-29,5 24,7-26 27,4-28,7
M 36 55 27,95-30,05 28-31,5 27,4-29 29,4-31
M 39 60 29,75-32,25 31,8-34,3 29,4-31 31,8-33,4
M 42 65 32,75-35,25 32,4-34,9 32,4-34 32,4-34
M 45 70 34,75-37,25 34,4-36,9 34,4-36 34,4-36
M 48 75 36,75-39,25 36,4-38,9 36,4-38 36,4-38
M 52 80 40,75-43,25 40,4-42,9 40,4-42 40,4-42

hex nut DIN 439 - ISO 4035: no dimensional differences.

© Ferrometal 08/2015

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 National standards in different countries:
Country Standard Country Standard
Algeria IANOR Korea, Dem. P. Rep. of CSK
Argentina IRAM Korea, Rep. of KATS
Australia SAI Libya LNCSM
Austria ON Malaysia DSM
Bangladesh BSTI Mexico DGN
Belgium IBN Mongolia MNCSM
Brazil ABNT Marocco SNIMA
Bulgaria BDS Netherlands NEN
Canada SCC New Zealand SNZ
Chile INN Nigeria SON
China CSBTS Norway NSF
Columbia ICONTEC Pakistan PSI
Cuba NC Philippines BPS
Cyprus CYS Poland PKN
Czech CSNI Portugal IPQ
Denmark DS Russia GOST
Egypt EOS Romania ASRO
Ethiopia QSAE Saudi Arabia SASO
Europe EN Singapore PSB
Finland SFS South Africa SABS
France AFNOR Spain AENOR
Germany DIN Sri Lanka SLSI
Ghana GSB Sweden SIS
Greece ELOT Switzerland SNV
Hungary MSZT Syria SASMO
India BIS Tanzania TBS
Indonesia BSN Thailand TISI
International ISO Trinidad & Tobago TTBS
Iran ISIRI Turkey TSE
Ireland NSAI United Kingdom BSI
Israel SII USA ANSI
Italy UNI Uzbekistan UZGOST
Jamaica JBS Venezuela FONDONORMA
Japan JISC Vietnam TCVN
Kenya KEBS Yugoslavia SZS

Technical delivery conditions and basic standards:

DIN (old) ISO DIN (new) or DIN EN Content

DIN 267 Part 20 - DIN EN 493 Fasteners, surface defects, nuts
DIN 267 Part 21 - DIN EN 493 Fastener elements, surface defects, nuts
DIN ISO 225 225 DIN EN 20225 Fasteners - Bolts, screws, studs and nuts. Symbols and designations of dimensions (ISO 225: 1991)
DIN ISO 273 273 DIN EN 20273 Fasteners - Clearance holes for bolts and screws (ISO 273:1991)
DIN ISO 898 Part 1 898 1 DIN EN 20898 Part 1 Mechanical properties of fasteners (ISO 898-1: 1988)
DIN 267 Part 4 898 2 DIN ISO 898 Part 2 Mechanical properties of fasteners - Part 2: Nuts with specified proof load values (ISO 898-2: 1992)
DIN ISO 898 Part 6 898 6 DIN EN 20898 Part 6 Mechanical properties of fasteners - Part 6: Nuts with specified proof load values. Fine pitch thread (ISO 898-6:
1988)
DIN 267 Part 19 6157-1 DIN EN 26157 Part 1 Fasteners - Surface discontinuities - Part 1: Bolts, screws and studs for general requirements (ISO 6157-1: 1988)
DIN 267 Part 19 6157-3 DIN EN 26157 Part 3 Fasteners - Surface discontinuities - Part 3: Bolts, screws and studs for special requirements (ISO 6157-3: 1988)
© Ferrometal 08/2015

DIN ISO 7721 7721 DIN EN 27721 Countersunk head screws - Head confirugation and gauging (ISO 7721: 1983)
DIN 267 Part 9 - DIN ISO 4042 Fasteners - Electroplated coatings
DIN 267 Part 19 - DIN ISO 8992 Fasteners - General requirements for bolts, screws, studs and nuts
DIN 267 Part 5 - DIN ISO 3269 Mechanical fastening elements - acceptance inspection

DIN 267 Part 11 - DIN ISO 3506 Stainless steel fasteners - technical delivery conditions
DIN 267 Part 12 - DIN EN ISO 2702 Heat-treated steel tapping screw. Mechanical properties.
DIN 267 Part 18 8839 DIN EN 28839 Mechanical properties of fasteners - bolts, screws, studs and nuts made of non-ferrous metals (ISO 8839: 1986)

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 2. Tolerances

Product’s dimensions are impossible to manufacture exactly right. Although products used in different machines and applications have to be accurate enough to fullfill three
main requirements:
• products have to function as required
• products have to be compatible so that machine or application can be assembled
• products have to be replaceable for example maintenance work done later on

These requirements are met by using acceptable variation in dimensions in manufacturing, known also as tolerances.

Main dimensional and geometrical tolerances for fasteners are shown in the following table:
© Ferrometal 08/2015

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 © Ferrometal 08/2015
Pict Feature Symbol Additional info Size Product class A Product class B Product class C NOTE!
(previously “m”) (previously “mg”) (previously “g”
1 Straightness t l = nominal length d≤8 0,0020 l + 0,05 2 X (0,0020 b + 0,05)
b = thread length d>8 0,0025 l + 0,05 2 X (0,0025 b + 0,05)
2 Thread length b P = pitch 0…+2P* * tolerace +2P is valid only if ls or lg is not specified in product standard
ls = non-threaded min length
lg = non-threaded max length

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stud bolt e js16 js17 js17
3 Thread toler- nut 6H 7H
ance screw 6g 8g
4 Head height outside k k < 10 js14 js15 js16
drive k ≥ 10 js17
inside drive k M≤5 h13 - -
M>5 h14
5 Head diameter dk h13* h14 - * in machine screws h14
6 Nut’s height m ≤ M12 h14 h17
> M12 ≤ h15
M18
> M18 h16
7 Nominal length l l ≤ 150 js15* js17 js17 * in machine screws l > 50 js16
l > 150 2 X js17
8 Shank diameter ds h13 h14 ± IT15
9 Slot width* n n≤1 +0,06…+0,20 - - * depth of slots and sockets: see product standards
1<n≤3 +0,06…+0,31
3<n≤6 +0,07…+0,37
10 Width outside s s ≤ 32 → h13 s ≤ 19 → h14
across drive s > 32 → h14 19 < s ≤ 60 → h15
flats 60 < s ≤ 180 → h16
s > 180 → h17
11 inside drive s s = 0,7 → EF8 - * tolerance range for socket set screws
s = 0,9 → JS9

7.70
s = 1,3 → K9
s = 1,5…2,0 → D10
(D9*)
s = 2,5 → D11 (D10*)
s = 3,0 → D11
s = 4,0 → E11
s = 5,0…14,0 → E12
(E11*)
s > 14,0 → D12

12 Angle 90° M ≤ 39 ± 1° ± 2°
M > 39 ± 1/2° ± 1°
Screws acc. to 84, 85, 444C, 478, 444B 95, 96, 97, 186, 188,
DIN-standard 479, 609, 610 ≥ M12, 261, 316, 444A, 525,
480, 561, 564, 609, 931, 933 > M24 529, 558, 571, 601,
610, 960, 961 603, 604, 605, 607,
653, 787, 835, 912, L>10d/>150mm 608, 6914, 7968,
931, 7969, 7990, 11014

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933, 938, 939, 940,
960,
961, 963, 964, 965,
966,
6912, 7380, 7513,
7516,
7971-7985, 7991
Nuts acc. to 439, 466, 467, 917, 439, 562, 934, 935, 314, 315, 555, 557,
DIN-standard 934, 936, 935
935, 936, 937, 979, 980 ≥ M16, 982 ≥
980, M16,
982 ≤ M12, 985 ≤ 985 ≥ M16, 1587,
M12, 6915,
986, 1587, 6330, 7965
6331

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 Standard tolerances and tolerance fields for internal and external dimensions:

Nominal (mm) Standard tolerances (mm) Tolerance fields for internal dimensions (mm)
> ≤ IT11 IT12 IT13 IT14 IT15 IT16 IT17 D12 F8 H6 H7 H8 H9 H10 H11 H12 H13 H14 H15
+0,12 +0,02 +0,006 +0,01 +0,014 +0,025 +0,04 +0,06 +0,1 +0,14 +0,25 +0,4
3 0,06 0,1 0,14 0,25 0,4 0,6 1
+0,02 +0,006 0 0 0 0 0 0 0 0 0 0
+0,15 +0,028 +0,008 +0,012 +0,018 +0,03 +0,048 +0,075 +0,12 +0,18 +0,3 +0,48
3 6 0,075 0,12 0,18 0,3 0,48 0,75 1,2
+0,03 +0,01 0 0 0 0 0 0 0 0 0 0
+0,19 +0,035 +0,009 +0,015 +0,022 +0,036 +0,058 +0,09 +0,15 +0,22 +0,36 +0,58
6 10 0,09 0,15 0,22 0,36 0,58 0,9 1,5
+0,04 +0,013 0 0 0 0 0 0 0 0 0 0
+0,23 +0,043 +0,011 +0,018 +0,027 +0,043 +0,07 +0,11 +0,18 +0,27 +0,43 +0,7
10 18 0,11 0,18 0,27 0,43 0,7 1,1 1,8
+0,05 +0,016 0 0 0 0 0 0 0 0 0 0
+0,275 +0,053 +0,013 +0,021 +0,033 +0,052 +0,084 +0,13 +0,21 +0,33 +0,52 +0,84
18 30 0,13 0,21 0,33 0,52 0,84 1,3 2,1
+0,065 +0,02 0 0 0 0 0 0 0 0 0 0
+0,33 +0,004 +0,016 +0,025 +0,039 +0,062 +0,1 +0,16 +0,25 +0,39 +0,62 +1
30 50 0,16 0,25 0,39 0,62 1 1,6 2,5
+0,08 +0,025 0 0 0 0 0 0 0 0 0 0
+0,4 +0,076 +0,019 +0,03 +0,046 +0,074 +0,12 +0,19 +0,3 +0,46 +0,74 +1,2
50 80 0,19 0,3 0,46 0,74 1,2 1,9 3
+0,1 +0,03 0 0 0 0 0 0 0 0 0 0
+0,47 +0,09 +0,022 +0,035 +0,054 +0,087 +0,14 +0,22 +0,35 +0,54 +0,87 +1,4
80 120 0,22 0,35 0,54 0,87 1,4 2,2 3,5
+0,12 +0,036 0 0 0 0 0 0 0 0 0 0
+0,545 +0,106 +0,025 +0,04 +0,063 +0,1 +0,16 +0,25 +0,4 +0,63 +1 +1,6
120 180 0,25 0,4 0,63 1 1,6 2,5 4
+0,145 +0,043 0 0 0 0 0 0 0 0 0 0
+0,63 +0,122 +0,029 +0,046 +0,072 +0,115 +0,185 +0,29 +0,46 +0,72 +1,15 +1,85
180 250 0,29 0,46 0,72 1,15 1,85 2,9 4,6
+0,17 +0,05 0 0 0 0 0 0 0 0 0 0
+0,71 +0,137 +0,032 +0,052 +0,081 +0,13 +0,21 +0,32 +0,52 +0,81 +1,3 +2,1
250 315 0,32 0,52 0,81 1,3 2,1 3,2 5,2
+0,19 +0,056 0 0 0 0 0 0 0 0 0 0
+0,78 +0,151 +0,036 +0,057 +0,089 +0,14 +0,23 +0,36 +0,57 +0,89 +1,4 +2,3
315 400 0,36 0,57 0,89 1,4 2,3 3,6 5,7
+0,21 +0,062 0 0 0 0 0 0 0 0 0 0
+0,86 +0,165 +0,04 +0,063 +0,097 +0,155 +0,25 +0,4 +0,63 +0,97 +1,55 +2,5
400 500 0,4 0,63 0,97 1,55 2,5 4 6,3
+0,23 +0,068 0 0 0 0 0 0 0 0 0 0

Nominal (mm) Tolerance fields for external dimensions (mm)

> ≤ f9 h6 h7 h8 h9 h10 h11 h12 h13 h14 h15 h16 h17 js14 js15 js16 js17 m6
-0,006 0 0 0 0 0 0 0 0 0 0 0 +0,008
3 ±0,125 ±0,2 ±0,3
-0,031 -0,006 -0,01 -0,014 -0,025 -0,04 -0,06 -0,1 -0,14 -0,25 -0,4 -0,6 +0,002
-0,01 0 0 0 0 0 0 0 0 0 0 0 0 +0,012
3 6 ±0,15 ±0,24 ±0,375 ±0,6
-0,04 -0,008 -0,012 -0,018 -0,03 -0,048 -0,075 -0,12 -0,18 -0,3 -0,48 -0,75 -1,2 +0,004
-0,013 0 0 0 0 0 0 0 0 0 0 0 0 +0,015
6 10 ±0,18 ±0,29 ±0,45 ±0,75
-0,049 -0,009 -0,015 -0,022 -0,036 -0,058 -0,09 -0,15 -0,22 -0,36 -0,58 -0,9 -1,5 +0,006
-0,016 0 0 0 0 0 0 0 0 0 0 0 0 +0,018
10 18 ±0,215 ±0,35 ±0,55 ±0,9
-0,059 -0,011 -0,018 -0,027 -0,043 -0,07 -0,11 -0,18 -0,27 -0,43 -0,7 -1,1 -1,8 +0,007
-0,02 0 0 0 0 0 0 0 0 0 0 0 0 +0,021
18 30 ±0,26 ±0,42 ±0,65 ±1,05
-0,070 -0,013 -0,021 -0,033 -0,052 -0,084 -0,13 -0,21 -0,33 -0,52 -0,84 -1,3 -2,1 +0,008
-0,025 0 0 0 0 0 0 0 0 0 0 0 0 +0,025
30 50 ±0,31 ±0,5 ±0,8 ±1,25
-0,087 -0,016 -0,025 -0,039 -0,062 -0,1 -0,16 -0,25 -0,39 -0,62 -1 -1,6 -2,5 +0,009
-0,03 0 0 0 0 0 0 0 0 0 0 0 0 +0,03
50 80 ±0,37 ±0,6 ±0,95 ±1,5
-0,104 -0,019 -0,03 -0,046 -0,074 -0,12 -0,19 -0,3 -0,46 -0,74 -1,2 -1,9 -3 +0,011
-0,036 0 0 0 0 0 0 0 0 0 0 0 0 +0,035
80 120 ±0,435 ±0,7 ±1,1 ±1,75
-0,123 -0,022 -0,035 -0,054 -0,087 -0,14 -0,22 -0,35 -0,54 -0,87 -1,4 -2,2 -3,5 +0,013
-0,043 0 0 0 0 0 0 0 0 0 0 0 0 +0,04
120 180 ±0,5 ±0,8 ±1,25 ±2
-0,143 -0,025 -0,04 -0,063 -0,1 -0,16 -0,25 -0,4 -0,63 -1 -1,6 -2,5 -4 +0,015
-0,05 0 0 0 0 0 0 0 0 0 0 0 0 +0,046
180 250 ±0,575 ±0,925 ±1,45 ±2,3
© Ferrometal 08/2015

-0,165 -0,029 -0,046 -0,072 -0,115 -0,185 -0,29 -0,46 -0,72 -1,15 -1,85 -2,9 -4,6 +0,017
-0,056 0 0 0 0 0 0 0 0 0 0 0 0 +0,052
250 315 ±0,65 ±1,05 ±1,6 ±2,6
-0,185 -0,032 -0,052 -0,081 -0,13 -0,21 -0,32 -0,52 -0,81 -1,3 -2,1 -3,2 -5,2 +0,02
-0,062 0 0 0 0 0 0 0 0 0 0 0 0 +0,057
315 400 ±0,7 ±1,15 ±1,8 ±2,85
-0,202 -0,036 -0,057 -0,089 -0,14 -0,23 -0,36 -0,57 -0,89 -1,4 -2,3 -3,6 -5,7 +0,021
-0,068 0 0 0 0 0 0 0 0 0 0 0 0 +0,063
400 500 ±0,775 ±1,25 ±2 ±3,15
-0,223 -0,04 -0,063 -0,097 -0,155 -0,25 -0,4 -0,63 -0,97 -1,55 -2,5 -4 -6,3 +0,023

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 3. Threads

Thread dimensions and accuracy of the profile are crucial when determining:
• whether the fastener can be surface treated
• whether the parts can be jointed together without problems
• whether the thread can transmit the forces for which the components are designed

Thread’s main dimensions are: nominal diameter, pitch and minor diameter:

There is different tolerance fields for screw and nut thread: screw thread dimensions are located below the nominal dimension and nut thread above. This leaves necessary
clearance for surface treatment. Standard ISO 965 recommends following tolerance fields for commercial grade fasteners:

6G 6G
6H

Välys ennen Clearance before

pintakäsittelyä surface treatment

6g
6e 6e
Major diam.

Major diam.
Kylkihalk.
Ulkohalk.

Pitch diam.

Pitch diam.

For threads M1,4 and above following tolerance fields are standard:
© Ferrometal 08/2015

Screw Nut Surface treatment

6g 6H plain, phosphated or electro zinc plated
6e 6G plain (big clearance) or thick platings

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 Dimensions for Metric ISO-threads, screws (6g) and nuts (6H):

M Pitch Screw, tolerance 6g Nut, tolerance 6H

P Major diameter d (mm) Pitch diameter d2 (mm) Pitch diameter D2 (mm) Minor diameter D1 (mm)
max min max min max min max min
2 0,4 1,981 1,886 1,721 1,654 1,830 1,740 1,679 1,567
2,5 0,45 2,480 2,380 2,188 2,117 2,303 2,208 2,138 2,013
3 0,5 2,980 2,874 2,655 2,580 2,775 2,675 2,599 2,459
3,5 0,6 3,479 3,354 3,089 3,004 3,222 3,110 3,010 2,850
4 0,7 3,978 3,838 3,523 3,433 3,663 3,545 3,422 3,242
5 0,8 4,976 4,826 4,456 4,361 4,605 4,480 4,334 4,134
6 1 5,974 5,794 5,324 5,212 5,500 5,350 5,153 4,917
7 1 6,974 6,794 6,324 6,212 6,500 6,350 6,153 5,917
8 1,25 7,972 7,760 7,160 7,042 7,348 7,188 6,912 6,647
10 1,5 9,968 9,732 8,994 8,862 9,206 9,026 8,676 8,376
12 1,75 11,966 11,701 10,829 10,679 11,063 10,863 10,441 10,106
14 2 13,962 13,682 12,663 12,503 12,913 12,701 12,210 11,835
16 2 15,962 15,682 14,663 14,503 14,913 14,701 14,210 13,835
18 2,5 17,958 17,623 16,334 16,164 16,600 16,376 15,744 15,294
20 2,5 19,958 19,623 18,334 18,164 18,600 18,376 17,744 17,294
22 2,5 21,958 21,623 20,334 20,164 20,600 20,376 19,744 19,294
24 3 23,952 23,577 22,003 21,803 22,316 22,051 21,252 20,752
27 3 26,952 26,577 25,003 24,803 25,316 25,051 24,252 23,752
30 3,5 29,947 29,522 27,674 27,462 28,007 27,727 26,771 26,211
33 3,5 32,947 32,522 30,674 30,462 31,007 30,727 29,771 29,211
36 4 35,940 35,465 33,342 33,118 33,702 33,402 32,270 31,670
39 4 38,940 38,465 26,342 26,118 36,702 36,402 35,270 34,670

Some common thread types are introduced in following table. The most typical thread is metric ISO-thread.

Symbol Name Thread type or application Marking Flank angle Standard

M Coarse thread Right hand M8 X 50 ISO 724
M-LH Fine thread Left hand M8 X 50 LH (DIN 13-1)
M Metric ISO-thread Coarse thread Right hand M8 X 1 X 50 60° ISO 724
M-LH Fine thread Left hand M8 X 1 X 50 (DIN 13-
LH 2…11)
M Metric conical male thread Grease nipples M20 X 1,5 DIN 158-1
cone
Female thread: symbol G G 3/4” ISO 228-1
G Non-sealing pipe thread
Male thread: symbol G and product cl. G 3/4” B
A or B 55°
R Conical male thread R 1½” DIN 2999-1
Rc Self-sealing pipe thread Conical female thread Rc 1½” DIN 3858
Rp Cylindrical female thread Rp 1½”
Tr Metric ISO-trapezoidal thread I.e. motion screws Tr 50 X 8 ISO 2901-4
30°
Rd Cylindrical round thread I.e. fire equipment joints Rd 20 X 3/4 DIN 405-1,2
ST Self tapping thread Self tapping screws ST 3,5 60° ISO 1478
UNC Inch size thread (USA) Coarse thread 3/4-10 UNC ANSI B 1.1
UNF Inch size thread (USA) Fine thread 3/4-16 UNF B.S. 1580-1.2
BSW Inch size thread (UK) Coarse thread 3/4-10 BSW 55° B.S. 84
BSF Inch size thread (UK) Fine thread 3/4-12 BSF
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 Properties for the inch sized threads:

Dimension Threads Per Inch (TPI)

inch mm UNC UNF Whitworth
1/4” 6,3 20 28 20
5/16” 7,9 18 24 18
3/8” 9,5 16 24 16
7/16” 11,1 14 20 14
1/2” 12,7 13 20 12
5/8” 15,9 11 18 11
3/4” 19,1 10 16 10
7/8” 22,2 9 14 9
1” 25,4 8 12 8
1 1/4” 31,8 7 12 7
1 1/2” 38,1 6 12 6
1 3/4” 44,5 5 - 5
2” 50,8 4½ - 4½
2 1/4” 57,1 4½ - 4
2 1/2” 63,5 4 - 4
2 3/4” 69,9 4 - 3½
3” 76,2 4 - 3½
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 4. Mechanical properties

Screw’s mechanical properties are presented in short in this section. Identifying these properties, it is essential to know terminology used.

Tensile strength Rm (N/mm2)

Tensile strength of a screw is the stress in which it can break. Breaking is allowed to happen in the screw’s shank or thread but not under the head. If testing is done with full-
size screws, the result is always approximate. To determine tensile strength accurately, machined test rod have to be pulled. Excluding stainless steel screws (material groups
A1…A5) which are always tested at full size (DIN ISO 3506).

Max. vetomurtolujuus
Max. vetomurtolujuus

Jännitys
Jännitys

0,2% -raja
Myötölujuus

Yield strength Re (N/mm2)

Yield strength indicates the tensile strength from which elongation begins to increase. Screw starts to yield when moving between elastic and plastic reformation area of the
material. Machined test rod should be used to determine also the accurate yield strength.
Venymä Venymä
Tensile-elongation diagram for class 5.6 screw: Max. tensile strength
Max. tensile strength

Tensile
Tensile

0,2% -limit
Yield strength

Max. vetomurtolujuus
Max. vetomurtolujuus

Jännitys
Jännitys

0,2% -raja
Myötölujuus

Elongation Elongation

0,2% -limit Rp0,2 (N/mm2)

The yield strength of harder material is difficult to define since there is no clear point where the elongation begins. Therefore it is taken into use term 0,2% -limit, where per-
manent elongation of 0,2% is remained after relief. This value is used for class 8.8 Venymä
Venymä and harder screws.

Tensile-elongation diagram for class 8.8 screw:

© Ferrometal 08/2015

Max. tensile strength

Max. tensile strength

Tensile
Tensile

0,2% -limit
Yield strength

Elongation Elongation

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 Breaking elongation A5 (%)
Breaking elongation indicates machined test rod’s elongation in percents: d0

A5 = (LU-LO) / LO X 100%, where

d0 = test rod’s / screw’s diameter before the test

LO = defined length LO = 5 X d0
LU = length after breaking L0 = 5 X d0

Hardness and it’s testing

In general, hardness is defined as the material’s ability to resist testing equipment’s penetration under surface. Three widely used systems for hardness testing are Brinell HB
(ISO 6506), Vickers HV (ISO 6507) and Rockwell A, B, C (ISO 6508).

Mechanical properties for screws in class 5.6…12.9:

Property class
Mechanical property 5.6 8.8 10.9 12.9
≤ M16* > M16*
Tensile strength Rm (N/mm2)** Nominal 500 800 1000 1200
min. 500 800 830 1040 1220
Yield strength Re (N/mm2)** Nominal 300 - - - -
min. 300 - - - -
0,2% -limit Rp0,2 (N/mm2)** Nominal - 640 640 900 1080
min. - 640 660 940 1100
Yield strength Re or + 100°C 270 590 875 1020
0,2%- limit Rp0,2 + 200°C 230 540 790 925
in high temperatures (N/mm2)
+ 250°C 215 510 745 875
+ 300°C 195 480 705 825
Breaking elongation A5 (%)** min. 20 12 9 8
Vickers-hardness F≤ 98N (HV)** min...max 155...220 250...320 255...335 320...380 385...435
*** 250 - - - -
Brinell-hardness F = 30D2 (HB)** min...max 147...209 238...304 242...318 304...361 366...414
*** 238 - - - -
HRB min...max 79…95 - - - -
Rockwell-hardness HR** *** 99,5 - - - -
HRC min...max - 22…32 23…34 32…39 39…44
Impact strength KV (J)** min. 25 30 30 20 15

* For structural bolts the limit is M12

** Properties in temperature + 20°C
*** Hardness value at the end of the bolt
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 Following hardness comparison table is valid only for carbon steels, low alloy steels and cast steels. For high alloy or austenitic steels, there can be major differences
expected.

Tensile Vickers- Brinell- Rockwell-hardness

strength hardness hardness 1) HRA HRB HRC
N/mm2 (F≥98 N)
305 95 90,2 52,0
320 100 95 56,2
335 105 99,8
350 110 105 62,3
370 115 109
385 120 114 66,7
400 125 119
415 130 124 71,2
430 135 128
450 140 133 75,0
465 145 138
480 150 143 78,7
495 155 147
510 160 152 81,7
530 165 156
545 170 162 85,0
560 175 166
575 180 171 87,1
595 185 176
610 190 181 89,5
625 195 185
640 200 190 91,5
660 205 195 92,5
675 210 199 93,5
690 215 204 94,0
705 220 209 95,0
720 225 214 96,0
740 230 219 96,7
755 235 223
770 240 228 60,7 98,1 20,3
785 245 233 61,2 21,3
800 250 238 61,6 99,5 22,2
820 255 242 62,0 23,1
835 260 247 62,4 24,0
850 265 252 62,7 24,8
865 270 257 63,1 25,6
880 275 261 63,5 26,4
900 280 268 63,8 27,1
915 285 271 64,2 27,8
930 290 276 64,5 28,5
950 295 280 64,8 29,2
965 300 285 65,2 29,8
995 310 295 65,8 31,0
1030 320 304 66,4 32,2
1060 330 314 67,0 33,3
1095 340 323 67,6 34,3
1125 350 333 68,1 35,5
1155 360 342 68,7 36,6
1190 370 352 69,2 37,7
1220 380 361 69,8 38,8
1255 390 371 70,3 39,8
© Ferrometal 08/2015

1290 400 380 70,8 40,8

1320 410 390 71,4 41,8
1350 420 399 71,8 42,7
1385 430 409 72,3 43,6

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 Material categories used in fasteners:

Carbon steel Several materials which properties as used in fasteners do not differ greatly from each other.

In exception are cold resistant materials below -50ºC and heat resistant materials over 300ºC.

Mechanical properties according to ISO 898.

Stainless steel Several materials which properties as used in ready end products differs a lot in means of corrosion resistance, heat resistance,
weldability, magnetization and hardening.

Mechanical properties according to ISO 3506.

Non-iron metals, e.g. Material codes, mechanical properties, testing methods and values and markings according to standards ISO 8839 / EN 28 839.
aluminium and copper
Other metals, e.g. brass No standards. In some cases, mechanical properties of carbon steel screws can be applied.
and titanium
Plastic No standards

Carbon steel (ISO 898)

ISO 898 covers metric bolts, screws, studs and nuts in coarse and fine threads up to size M39.

PROPERTY CLASS
Screw 3.6 4.6 4.8 5.6 5.8 6.8 8.8 9.8 10.9 12.9
Nuts 4 5 6 8 9 10 12
04 05

Screws
Property class is defined in format A.B

A is 1/100 of tensile strength (Rm = 100 x A)

B is multiplication of tensile strength x yield strength x 10 (Re = 10 x A x B)

e.g. 8.8 = Rm = 800 MPa ja Re = 640 MPa

Nuts

ISO 898-2 defines coarse thread nuts.

ISO 898-6 defines fine thread nuts.

The symbol for property class is a number which indicates for which property class screw the nut can be jointed (first number of the screw’s property class).

For low height nuts the property classes are 04 and 05.
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 Head marks

Zinc plated / Plain

Marking according to ISO 898-1.

Hexagon head screws and nuts with thread diameter M5 and above
have to be marked as shown in the picture.

Stainless steels (A4 / A2)

Manufacturer´s mark

Marking according to ISO 3506-1.

Hexagon head screws with thread diameter M5 and above have to

be marked as shown in the picture. Steel grade, property class and
manufacturer’s mark has to be visible in the stamp.

Steel grade Property class

Hexagon nut with thread diameter M5 and above have to be marked

as shown in the picture. Marking can be made also to the across flats
–surface..

Alternative marking for A4 / A2 hexagon nuts

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 Stainless steels (ISO 3506)

Steel groups according to ISO 3506:

Steel
TERÄS-
group Austenitic
Austeniittinen Ferritic
Ferriittinen Martensitic
Martensiittinen
RYHMÄ

Steel
TERÄS-
group A1 A2 A3 A4 A5 F1 C1 C4 C3
LUOKKA

Steel
LUJUUS-
group
LUOKKA 50 70 80 45 60 50 70 110 50 70 80

and
tempered
Hardened and
tempered
Soft

and
tempered
Soft
Pehmeä

Pehmeä

Pehmeä

Pehmeä
Work

Soft
hardened

Work
hardened

Hardened
tempered
Muokkaus-

muokkaus-

Muokkaus-
Soft

lujittunut

lujittunut

lujittunut
Heavily
work
hardened

Nuorrutettu
Nuorrutettu

Nuorrutettu

Nuorrutettu
Voimakkaasti

Hardened

Hardened

and
A1 Machineable grade. Limited properties for corrosion protection and weldabilty. Similar classification in AISI-standard: AISI 303. Non-magnetic, non-hardening.
A2 Most common grade of stainless steels used e.g. in chemical industry and in household devices. Rustproof, acidproof and weldable. Do not apply for non-oxidiz-
ing acids nor chlorine-rich environments e.g. to sea water.
Similar classification in AISI-standard: AISI 304. Non-magnetic, non-hardening. Cold-resistant down to - 200 °C
A3 Properties as in A2. Non-magnetic, non-hardening.
A4 Most common garde of “acidproof” steels. Resistant to many acids depending of temperature, reasonable resistant in chlorine-rich environments. Good weldabil-
ity. Widely used in wood-processing, food-processing and ship-building industry. Non-magnetic, non-hardening. Cold-resistant down to - 60 °C Similar classifica-
tion in AISI-standard: AISI 316.
A5 Properties as in A4. Non-magnetic, non-hardening.
F1 Magnetic grade. In some cases A2 can be replaced by F1 which have good resistance to chlorine.
C1 Hardening grade. Quite good corrosion resistance when surface treated (e.g. Delta –plating). Magnetic. Similar classification in AISI-standard: AISI 410.
C3 Limited properties for corrosion protection.
C4 Limited properties for corrosion protection. Machineable.

Temperature effect on corrosion: Environment’s chemical compound and temperature have a great effect on stainless steel’s
corrosion resistance.

Friction coefficent is high on stainless steel’s surface (appr. 0,40…0,50). Therefore lubrication or waxation is needed before
mounting.

Stainless steels are identified with following letter-number combination:

A2 - 70

Steel groups´s symbol

A = Austenitic steel

Steel grade´s symbol

1 = Automatic steel, sulphur surcharge
2 = Cold formed steel, chrome/nickel compound
3 = Cold formed steel, chrome/nickel compound + Ti, Nb, Ta
4 = Cold formed steel, chrome/nickel/molybdene compound
5 = Cold formed steel, chrome/nickel/molybdene compound
+ Ti, Nb, Ta
© Ferrometal 08/2015

Property class symbol

50 = 1/10 of tensile strenght (min. 500 N/mm2)
70 = 1/10 of tensile strenght (min. 700 N/mm2)
80 = 1/10 of tensile strenght (min. 800/Nmm2)

When there is no symbol for the property class, it is regarded as class 50.
In common speech, description of fasteners:
A2 = “Rustproof fastener”
A4 = “Acidproof fastener”

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 Chemical analysis for austenitic steel group:

Material Mat. C Si Mn Cr Mo Ni
nro ≤% ≤% ≤% % % %

A2 X5 Cr Ni 1810 1.4301 0,07 1,0 2,0 17,0 - 8,5

- -
20,0 10,0
X2 Cr Ni 1811 1.4306 0,03 1,0 2,0 17,0 - 10,0
- -
20,0 12,5
X8 Cr Ni 19/10 1.4303 0,07 1,0 2,0 17,0 - 10,5
- -
20,0 12,0
A3 X6 Cr Ni Ti 1811 1.4541 0,10 1,0 2,0 17,0 - 9,0
- -
19,0 11,5
A4 X5 Cr Ni Mo 1712 1.4401 0,07 1,0 2,0 16,5 2,0 10,5
- - -
18,5 2,5 13,5
X3 Cr Ni Mo 1712 1.4404 0,03 1,0 2,0 16,5 2,0 11,0
- - -
18,5 2,5 14,0
A5 X6 Cr Ni Mo Ti 1.4571 0,10 1,0 2,0 16,5 2,0 10,5
1712 - - -
18,5 2,5 13,5

Mechanical properties for austenitic steel group:

Steel group Steel Property Diam. Screws

grade class range
Tensile - 0,2% limit Breaking
strength Rp 0,2 1) elongation
Rm 1) N/mm2 A 2)
N/mm2 min. mm
min. min.
Austenitic A1, A2, 50 ≤ M 39 500 210 0,6 d
A3, A4
70 ≤ M 24 700 450 0,4 d
and A5
80 ≤ M 24 800 600 0,3 d

1)
The tensile stress is calculated on the stress area (see ISO 3506-1 annex A).
2)
To be determined on actual screw length, not on prepared test piece.
d = nominal thread diameter
Mechanical properties at elevated temperatures; application at low temperatures (ISO 3506-1):

For values for lower yield stress Re and stress at 0,2 % permanent strain Rp0,2 at elevated temperatures in % of the values at room temperature.

Steel grade Re and Rp0,2 (%)

in temperature
+ 100 °C + 200 °C + 300 °C + 400 °C
A2, A4 85% 80% 75% 70%
C1 95% 90% 80% 65%
C3 90% 85% 80% 60%
Note! This applies to property classes 70 and 80 only.
© Ferrometal 08/2015

For application of stainless steel bolts, screws and studs at low temperatures:

Steel grade Lower limits of operational temperature at continuous operation

A2 - 200 °C
A4 Bolts and screws 1) - 60 °C
Studs - 200 °C
1) In connection with the alloying element Mo the stability of the austenite is reduced and the transition
temperature is shifted to higher values if a high degree of deformation during manufacturing of the
fastener is applied.

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 Arguments for using austenitic (A1, A2 ja A4) fasteners:

Advantage Potential problem

Bright surface, nice appearance Poor quality impression of the end product due to screws in rust.

Safety Corrosion in fasteners reduces their strength and operational features.

No rust marks Red rust can colour e.g. plastics and textiles. Stainless stell fastener is easy to clean and it is hygienic.

If you cut yourself into a rusty part it can lead to blood poisoning. Zinc plated fasteners must be kept
No health risks
out of touch with food stuff and out of reach of children (licking).

Austenitic chrome-nickel steels are almost completely

Use of magnetic fasteners in e.g. sensitive measuring devices can lead into faulty readings.
non-magnetical
In above 80°C temperatures, zinc plating’s chromating will destroy which leads to dramatical drop in
High temperature resistance
corrosion resistance.
Screws and nuts in rust are difficult to open. This requires extra effort and time. To disassemble the
Easy maintenance
joint, rusty fasteners often have to be broken. This may cause damage also to the clamped parts.

Screws and nuts from heat and cold resistant materials (DIN 267-13):

Temperature ˚C Material Symbol Material No.

C 35 N Y 1.0501
Up to+350 ˚C Cq 35 YQ 1.1172
Ck 35 YK 1.1181
Up to+400 ˚C 24 CrMo 5 G 1.7258
Up to +540 ˚C 21 CrMoV 57 GA 1.7709
Up to +540 ˚C 40 CrMoV 47 GB 1.7711
Up to +580 ˚C X 22 CrMoV V 1.4923
Up to +580 ˚C X 19 CrMoVNbN VW 1.4913
Up to +650 ˚C X 8 CrNiMoBNv 16 16 S 1.4986
Up to +700 ˚C X 5 NiCrTi 26 15 SD 1.4980
Up to +700 ˚C NiCr 20 TiAl SB 2.4952

-65 ˚C 26 CrMo 4 KA 1.7219

-140 ˚C 12 Ni 19 KB 1.5680
-253 ˚C X 12 CrNi 18 9 KC 1.6900
-253 ˚C X 10 CrNiTi 18 10 KD 1.6903
X 5 CrNi 18 9 1.4301
-196 ˚C X 5 CrNi 19 11 A2 1.4303
X 10 CrNiTi 18 9 1.4541
-60 ˚C X 10 CrNiMo Ti 18 10 A4 1.4571
X 5 CrNiMo 18 10 1.4401
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 5. Quality and testing

All fasteners properties are defined in DIN-, ISO- or EN-standards as follows:

Product standard (e.g. DIN 931 / ISO 4014):

Includes information about product’s form, version, tolerance (product grade A, B, C), strength or material and nominal dimensions. Product standards always refers to valid
basic standards.

Basic standard (e.g. DIN 13, ISO 898/4759/3269):

Includes general information for example of threads, tolerances, surface treatments, mechanical properties and testing.

Fasteners according to standards fullfill the demands for ”normal use” (ISO 3269/8992). For more demanding special applications, extra testing or other requirements must
be defined before ordering by the customer.

Basic standards require testing programs and processes with which manufacturers guarantees their quality inspecting random samples. In addtion to these tests Ferrometal
Oy performs continual quality control of in-coming goods.

Economical mass production for standard fasteners is not possible without nonconforming items. ISO 3269 introduces acceptable quality level (AQL) which is a statistical
procedure for quality definition. AQL gives quality level in a sampling plan corresponding to a high probability of acceptance. From the results the whole manufacturing lot’s
quality can be determined. AQL –value depends of:
• product: screw, nut, washer, bolt, pin, rivet
• product (tolerance) class: A, B or C
• main characteristic: AQL-value = 1,5…1,0
• secondary characteristic: AQL-value = 4,0…2,5
• mechanical characteristic: AQL-value = 1,5…0,65

Main characteristic includes all the main properties for the functioning of the product, like: head / slot / socket, thread etc. Secondary characteristic may include slight devia-
tions in dimensions or forms not affecting to the product’s function or suitability.

AQL-values for threaded fasteners according to dimensional characteristics:

Product group
1 2 3 4 5 6
All thread-forming
Dimensional Bolts, screws and Bolts, screws and screws not cov-
characteristics Nuts in product Nuts in product Self-tapping screws
studs in product studs in product ered in group 5,
class A and B class C and wood screws
class A and B class C self-drilling and
chipboard screws
AQL
Width across flats 1 1,5 1 1,5 1,5 1
Width across corners 1 1,5 1 1,5 1,5 1
Nut height - - 1 1,5 - -
Width of slot 1 - - - 1,5 1
Depth of slot 1 - - - 1,5 1
Recess penetration 1 - - - 1,5 1
Socket, GO gauge 1 - - - - -
Socket, NOT GO gauge 1 - - - - -
Configuration under head 1 - - - - 1
Thread, GO gauge 1 1,5 1 1,5 - 1
Thread, NOT GO gauge 1 1,5 1 1,5 - 1
Major diameter - - - - 2,5 1
Geometric tolerances 1 1,5 1 1,5 2,5 1
All others 1,5 2,5 1,5 2,5 2,5 1,5
Nonconforming fasteners 2,5 4 2,5 4 4 2,5
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 Characteristics AQL Reference standard

Non-destructive tests a 0,65

Mechanical characteristics and
surface integrity ISO 898 c
Destructive tests 1,5 ISO 2320
ISO 2702
ISO 3056 c
Chemical composition 1,5
ISO 6157 c
ISO 7085
Metallurgical characteristics 1,5 ISO 8839
etc.

Functional (performance) characteristics 1,5

ISO 4042
Coating 1,5
ISO 10683

Others b 1,5

a
If non-permitted surface discontinuities (for example, quench cracks) are found during surface discontinuity inspection (non-
destructive test), regardless of their size, the inspection lot shall be rejected.

b
Other characteristics may be required according to applicable specifications

c
See the applicable parts of these standards
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 In the acceptance inspection it is taken into account the size of production lot. (defined by the manufacturer), suitable LQ10 –value and the sample size. Example of sam-
pling plan where acceptance number Ac can be read:

AQL
0,65 1,0 1,5 2,5 4,0
Ac
n (pcs)
LQ10 (%)

8 5 3
0 - -
25 37 54

50 32 20 13 8
1
7,6 12 18 27 42

125 80 50 32 20
2
4,3 6,5 10 17 25

200 125 100 50 32

3
3,3 5,4 6,6 13 20

315 200 125 80 50

4
2,6 3,9 6,2 9,6 15

400 250 160 100

5 -
2,4 3,7 5,8 9,3

315 200 125 80

6 -
3,4 5,2 8,4 13

400 250 160 100

7 -
3,0 4,7 7,3 11,5

315 200 125

8 - -
4,2 6,6 10

400 250 160

10 - -
3,9 6,0 9,5

315 200
12 - - -
5,6 8,8

400 250
14 - - -
5,0 8,0

315
18 - - - -
7,8

400
22 - - - -
7,3

Ac = Acceptance number. It is the maximum number of nonconformities of the same characteristic in any given sample which, when exceeded, causes the lot to be rejected.

n = Sample size, number of fasteners in a sample

LQ10 = Limiting quality. Quality level in a sampling plan corresponding to a low probability of acceptance. LQ10 is the percentage of fastemers that do not conform in
respect of product characteristic, having one chance in ten of being accepted under the sampling plan; often referred to as the
consumer’s risk.

Zero nonconformity deliveries always require additional testing and they must be agreed prior to ordering. otherwise ISO 3269 is applied.
© Ferrometal 08/2015

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 Material certificates, Pressure Equipment Directive.

Additional tests can be carried out accordance to the special request of the customer. Results of these tests are documentated into a certificate which is delivered to the
customer.

For certain fastener groups, Ferrometal Oy has available the most commonly used Inspection certificate 3.1B. Our catalogue prices do not include certficate expenses.

EN 10204 Designation Inspection Test results Validated by

2.1 Declaration of compliance No determination of test results No results

The manufacturer
Indication of results of non-specific
2.2 Test report Chemical analysis
insopection

3.1 Inspection certificate The manufacturer

The test unit and the tests to be

carried out are defined by the product Chemical analysis and
specification, the official regulation mechanical properties
and/or the order
The inspector authorized by the
3.2 Inspection certificate manufacturer and the purchaser or by the
official regulations

NOTE! None of these certificates is capable to fullfill the requirements set by the Pressure Equipment Directive (PED; EN 13445, EN 12962, EN 12953, EN
13488). Ask for more information about the PED requirements from Ferrometal Oy sales.
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 6. Surface treatments and corrosion

Corrosion in screw joints

Corrosion resistance for all steels base on two factors – either to their natural nobleness in electrochemical series or to their ability to produce corrosion protective layer to
their surface (e.g. aluminium or stainless steels).

Stainless steels include at least 16% of chromium (Cr) and they are resistant against oxidizing environments. With higher amount of chromium and with other components
like nickel (Ni), molybdene (Mo), titanium (Ti) or niobium (Nb) the corrosion resistance can be improved. These components have an effect also the steels mechanical
properties.

Fasteners in austenitic steel group are not usually magnetic. Magnetization can be achieved through cold forming. This do not affect on corrosion resistance.

Main factors for corrosion generation:

1. Surface corrosion
2. Stress corrosion
3. Hole corrosion
4. Intergranular corrosion
5. Evosive corrosion
6. Salvanic corrosion
7. Mechanical causes

1. Surface corrosion

Surface corrosion means steady and slowly proceeding corrosion in the surface. It is common type of corrosion for plain metal surfaces and zinc plated fasteners. This
corrosion type can be avoided by a careful material selection, see later on “A4 / A2 chemical resistance”.

Local corrosion, point corrosion exists as surface corrosion with addition of local hole and crack formation. Point corrosion starts from uneven surfaces and it exists typically
in fasteners which corrosion protection is produced by passive film or zinc plating / painting.

Local corrosion erosion occurs in stainless steels fasteners when they are in contact with chlorine or borium rich environment. Swimming pool areas for example.

Austenitic steels, like A2 and A4, are more local corrosion resistant than ferritic chrome steels..

2. Stress corrosion

This type of corrosion occurs generally on parts in industrial environments which are exposed to strong mechanical loads of tensile and bending. Residual stress generated
e.g. from welding can also lead to stress corrosion.

Austenitic steels in a chlorine rich atmosphere are especially sensitive to stress corrosion.
Temperatures over 50 °C makes them even more sensitive.

4. Intergranular corrosion

This type of corrosion is essentially joined into high temperature, e.g. from welding or heat treatment. Corrosion causing substances are formated into grain boundary of the
steel and it will rust along the grain boundaries.

A4 / A2 steels are also sensible to this corrosion type, when it is called sensitization of stainless steels. Austenitic steel is sensitized in temperature 550…800 °C. Chromium
carbide forms at the intergranular boundaries, depleting the grain edges of chromium, impairing their corrosion resistance.

5. Erosive corrosion

Erosive corrosion exists because of the movement of solution which is in touch with the material. The corrosion protection of the surface is worn because of the solution flow,
for example in pipe curves.
© Ferrometal 08/2015

This is not typical corrosion type in screw joints.

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 6. Galvanic corrosion
Galvanic corrosion, also known as contact corrosion, occurs when two parts of different composition are in metallic contact. As humidity acts like electrolyte, the lower grade
element in the electrochemical series will corrode.

This typical corrosion type also in the screw joints where exists potential difference between metals and humidity acting as electrolyte.

Chemical tension of metals

Electrochemical series for metals Carbon

There exists potential difference between different Platinium
metals. The more far away the metals are from Gold
each other in the attached electrochemical series, Silver
the larger is the potential difference and risk for Stainless steel, passivated
corrosion. Nickel

Noble
Copper
Brass
Tin
Stainless steel, not passivated

Un-noble
Lead
Carbon steel
Cadmium
Aluminium
Zinc plated steel
Zinc
Magnesium

HUMIDITY CURRENT HUMIDITY CURRENT

COPPER ALUMINIUM

CARBON STEEL SCREW CARBON STEEL SCREW

In this screw joint carbon steel screw acts as Carbon steel screw acts again as cathode in this
cathode and copper material as anode, the screw screw joint. Aluminium material acts as anode and
will rust because it is lower in the electrochemical it will rust due to it’s position in the series.
series.

HUMIDITY (ELEKTROLYYTTI)
KOSTEUSKALVO RUST
RUOSTETTA Slag or impurity in the same material leads into
the corrosion of the base material. Humidity acts
SLAG
KUONA(CATHODE)
(KATODI)
as electrolyte.
CURRENT
VIRTA

TERÄS (ANODI)

Galvanic corrosion will activate when:

1. Air humidity exceeds 60%
2. Impurity in the air: lot of metallic particles
3. Metals with big potential difference in the same screw joint
4. Wrong ratio of surface area for anode & cathode
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 How to prevent corrosion?
1. Disable galvanic pair.
- protect structures from humidity (remove the electrolyte)
- insulate different metals from each other with e.g. surface treatments
- insulate metals from the electrolyte

2. Avoid using metals with big potential difference.

3. Arrange good ventilation for the structure and screw joint.

4. Choose screws from more noble potential than the structure. Strucutre with less noble
potential should have larger surface area than the screw.

5. Choose adequate surface treatment.

6. Arrange temperature as low as possible.

7. Choose the right fasteners: avoid zinc plated fasteners with low corrosion resistance.

NOTE! Stainless fasteners in class A4 are not sufficient in chlorium-rich environments

such as swimming pool areas. Ask for suitable application from Ferrometal Oy sales.

A4 / A2 Chemical resistance

Recistance grade Evaluation Weight loss

g/m2h
A Fully resistant < 0,1
B Practically resistant 0,1 - 1,0
C Low resistance 1,0 - 10
D No resistance > 10
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 Corrosive agent Concentration Temperature °C Resistance
grade

A2 A4

Ammonia all 20 A A
boiling A A

Acetone all all A A

Petrol - all A A

Benzol - all A A

Benzoic acid all all A A

Mercury - < 50 A A

Mercury nitrate - all A A

Vinegar acid 10% 20 A A

boiling A A

Ethyl alcohol all 20 A A

Ethyl ether - all A A

Pheno pure boiling B A

Phosphoric acid 10% boiling A A

50% 20 A A
boiling C B
80% 20 B A
boiling D C
conc. 20 B A
boiling D D

Glycerine concentrated all A A

Fruit - - A A

Fruit juice - all A A

Carbon dioxide - - A A

Lime - - A A

Developer - 20 A A
(photography)

Chlorine dry gas 20 A A

humid gas all D D

Chloroform all all A A

Copper acetate - all A A

Copper nitrate - - A A

Copper sulphate - - A A

Magnesium sulphate ca. 26 % all A A

Milk acid 1,5 % all A A

10 % 20 A A
boiling C A

Sea water - 20 A A

Methyl alcohol all all A A

Formic acid 10% 20 A A

boiling B A
© Ferrometal 08/2015

Sodium hydroxide 20 % 20 A A
boiling B B
50 % 120 C C

Sodium carbonate - all A A

Sodium nitrate - all A A

Beer - all A A

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 Corrosive Concentration Temperature °C Resistance grade
agent
A2 A4

Oxalic acid 10 % 20 B A
boiling C C
50 % boiling D C

Tannic acid all all A A

Petroleum - all A A

Fat acid 150 A A

180 B A
200-235 C A

Sulphuric dioxide - 100-500 C A

900 D C

Sulphuric acid 2,5 % < 70 B A

boiling C C
5% 20 B A
> 70 B B
10% 20 C B
70 C C
60 % all D D

Sulphurous acid Watery solution 20 A A

Salicylic acid - 20 A A

Citric acid < 10 % all A A

50 % 20 A A
boiling C B

Lemon juice - 20 A A

Sugar solution - all A A

Hydrochloric 0,2 % 20 B B
acid 50 C B
2% 20 D D
50 D D
< 10 % 20 D D

Cyanide - 20 A A

Industrial air - - A A

Tar - hot A A

Nitric acid < 40 % all A A

50 % 20 A A
boiling B B
90 % 20 A A
boiling C C

Blood - 20 A A

Wine - 20 and hot A A

Wine acid < 10 % 20 A A

boiling B A
> 10 % 20 A A
< 50 % boiling C C
75 % boiling C C

Oils (mineral) - all A A

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 Meaning of the zinc layer thickness

Zinc electroplating produces significantly thinner layer than hot dip galvanizing. Zinc plated fastener is applies only to use in dry indoor air. For outdoor use zinc plating is not suitable.

Hot dip galvanizing layer is almost evenly thick in the fastener surface, just opposite as in the zinc plating.

60
Zinc plating

ies
cit
mall
s ,s
50 rea
ta
as
Co
nd

40
inla
,
eas
l ar
a
Rur

30

ies
e cit
Larg
20

as
ial are
Industr
10

g / m2
100 300 500 700 900 1100

µm
10 20 40 60 80 100 120 140 160

Values in the chart are approximate

Hydrogen embrittlement

Both electro zinc plating and hot dip galvanizing (acid pickling phase before coating) processes can weaken dramatically and randomly fastener’s mechanical properties. In these processes, hydro-
gen is dissolved into the metal and it will lead into hydrogen embrittlement. This causes inner cracks in the metal and formation of pores.

Fasteners above class 8.8 are not recommended to be electro zinc plated nor hot dip galvanized due to the risk of hydrogen embrittlement. Heat treatment after metal coating process will reduce
the risk, but however it is not guaranteed that hydrogen embrittlement will be completely removed.

If total surety is needed, alternative types of corrosion protection should be selected: anorganic zinc coatings (Delta, Ruspert, Dacromet etc.), mechanical galvanization or a change to stainless steel
fasteners.

Environment’s corrosion effect

Fastener’s and structure’s tendency for corrosion can be determined by classification of the environment’s stress.

ISO 12944-2 SFS 4596 Corrosion Typical environments

Classifica- Classifica- effect
tion tion

M0 No stress
C1 M1 Very light stress Dry, heated interiors.
C2 M2 Light stress Heated interiors, danger of condensa-
tion. Rural areas, low pollution.
C3 M3 Moderate stress Urban areas. Interiors with high
humidity.
C4 M3 Moderate stress Industrial and coastal environments,
chemical processing plants, swimming
© Ferrometal 08/2015

pool areas.
C5-1 M4 Heavy stress Industrial environments with aggres-
sive atmosphere.
C5-2 M4 Heavy stress Offshore atmosphere.

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 Other commonly used surface treatments

Surface Max.
Explanation
treatment Temperature
Disc coating with high values of zinc and aluminium can be manufactured in different colors. Depending on the layer thickness,
Ruspert -
500h or 1000h resistance in the salt spray test.

Dipping in a zinc bath with temperature between 440…470 °C. Layer thickness is min. 40µm. Finish is dull and rough, color
Hot Dip
change is possible after a certain time. Gives very good corrosion protection. Applicable only for threads M8 and above. Threads 250 °C
Galvanizing
need to be under or overcutted to ensure proper fitting.
Only light corrosion protection. With oiled surface gives better resistance against rust. Good base layer for painting. Finish
Phosphating 70 °C
appearance from grey to grey/black.
Good coating with high content of zinc (silver grey color) for parts with high tensile strength,
Dacromet Rm ≥ 1000 N / mm2 or hardness ≥ HV 300. Can be applied to threads M4 and above. No risk for 300 °C
hydrogen embrittelement.

Chemical-mechanical coating process. Degreased items are put together with crystall ball mix and zinc powder into a plating
Mechanical plating -
drum. Crystall balls act as bearers of the zinc powder flakes and adheres them onto the item’s surface through cold welding.

Delta -microsurface

Delta-Tone is an inorganic basecoat which is based on zinc and aluminium lamella. Delta-Tone is conducting and it formates a cathodic corrosion protection.

Delta-Seal is an organic topcpat which can be used together with Delta-tone basecoat which improves the corrosion protection even more. Delta-Seal surface is hard and
very low-frictioned. It is suitable for food applications and it do not include chrome 6, lead, cadmium or other heavy metals.

Applications by: Dip-spin, dip-drain, spraying, spin coating. Surface treatment can be done in one or multiple layers; final film thickness between 4…20 µm. After ap-
plication follows heat treatment, typically 20 minutes in 200 ˚C.

Heat resistance +250 ˚C.

Excellent corrosion protection reached – 800 hours salt spray test according to DIN 50021 and minimum of 10 rounds in Kesternich test according to DIN 50018.

Ferrometal Oy delivers fasteners also with Delta –plating.

Ask for more from Ferrometal Oy sales.

Delta-Tone Delta-Seal Delta-Tone+ Electro zinc Hot Dip

Delta-Seal plating Galvanizing

Cathodic yes No yes yes yes

protection
Electric Conducting Insulating Insulating Conducting Conducting
protection
Risk of hydrogen no no no yes yes
embrittlement
Chrome 6 no no no yes 1) yes
Friction coef- yes yes yes no no
ficient
0,08…0,14
Re-mountable yes/no yes yes yes/no yes
Acid and base no yes yes no no
proof
Black color no yes yes yes no
Silver color yes yes yes yes yes
© Ferrometal 08/2015

Yellow color no no no yes no

Other colors no yes yes no no

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 Markings of electroplated coatings

Standard ISO 4042 defines the symbols for markings of electroplated coatings for fasteners:

A2F
1. Identifying symbol for coating
A = zinc (Zn)

2. Identifying symbol for thickness

2 = 5 µm

3. Identifying symbol for appearance

and passivating
F = semi-bright, blue passivated

1. Coating material 2. Coating thickness

A = Zinc (Zn) 1 = 3 µm
B = Cadmium (Cd) 2 = 5 µm
C = Copper (Cu) 3 = 8 µm
D = Brass (CuZn) 9 = 10 µm
E = Nickel (Ni) 4 = 12 µm
F = Nickel-chrome (NiCr) 5 = 15 µm
G = Copper-nickel (CuNi) 6 = 20 µm
H = Copper-nickel-chrome (CuNiCr) 7 = 25 µm
J = Tin (Sn) 8 = 30 µm

3. Appearance (passivating / chromating)

A no color
B blue
= dull
C yellow
D olive
E no color
F blue
= semi-bright
G yellow
H olive
J no color
K blue
= bright
L yellow
M olive
R dull
S = semi-bright black
T bright

Hot dip galvanized coatings

Fasteners to be hot dip galvanized (ISO 10684) should be threaded to special dimensions. Since hot dip galvanizing coating thickness is always above 40 µm, zinc layer
needs enough clearance to fit after coating into normal commercial grade tolerance 6g / 6H.

In practice, this can be done with two methods:

1) Screws are undersized into tolerance class 6az before hot dip galvanizing. After coating they will fit to nuts with tolerance class 6H (normal commercial grade) and they
are convertible with screws in tolerance class 6g.

2) Screws with normal tolerance class 6g are hot dip galvanized and they become oversized. Since they do not fit to normal 6H nuts, nuts have to be oversized into toler-
ance class 6AZ or 6AX after hot dip galvanizing. Nuts and other female threaded parts have to be tapped always after coating.

Ferrometal stocks screws manufactured according to method 1) (so called ISO-fittting).

NOTE!
M8 and M10 undersized screws and oversized nuts mechanical properties are slightly lower than specified in ISO 898-1 and ISO 898-2. Tensile strengths and proof loads
for M8 and M10 can be found in ISO 10684 annex A.

Diameters M12 and above must be according to ISO 898-1 and ISO 898-2.
© Ferrometal 08/2015

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 Most common short names in Ferrometal Oy for surface treatments:
plain ST
electro zinc plated ZN
yellow passivated ZNC
hot dip galvanized HOT
phosphated FOS

Color codes for threaded rods according to DIN 975/ 976:

Material Color RAL-code

Class 4.8 no color -
Class 5.6 brown RAL 8015
Class 5.8 blue RAL 5010
Class 8.8 yellow RAL 1023
Class 10.9 white RAL 1013
Class 12.9 black RAL 9017
A2-70 green RAL 6024
A4-70 red RAL 3000
© Ferrometal 08/2015

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 7. Screw joints

Screw joint is the most common dismountable joint in machine building since it is easy to mount and dismount, reliable when used right and it can be used in many environ-
ments. Moreover, standard fasteners are relatively inexpensive items.

One of screw joint’s drawbacks is reliability because of difficult control of tightening torque. Screws also have discontinuity points where stresses are high. In most screw
joints, loading forces are tensile force parallel to screw’s axle and shear force perpendicular to that.

In tapping and fitting screws shear force can affect straight into the screw which generates shear stress. Demanding screw joints are designed so that friction force caused by
axial force will transfer shear force from item to another. This way, the only shear force left in the screw shank is the torque shear stress possibly left from tightening of the nut.

Screw’s tensile strength is the most important feature in durability of the joint. When the screw is loaded statically, it can break in following ways:
• screw will break when tensile strength exceeds it’s breaking strength
• screw’s thread breaks
• nut’s thread breaks

When the threads of screw and nut are strong enough to transfer the axial force from screw to nut, the screw is the one which have to fail. It should break from the thread or
from the shank, but never from the head.

Thread’s manufacturing method have a great effect on screw’s fatigue strength. In practical, there is two different ways for thread manufacturing: cutting or rolling. Standard
screws are usually threaded by rolling in cold. Very big diameters and small production batches can be made also in hot rolling. Cold rolled threads have better fatigue
strength than cutted ones because of thread’s smoothening and plastic deformation.

Right pretensioning is crucial in order to achieve a reliable screw joint. It has to be adequate, but not too big. The more specific pretensioning can be made, the lighter and
inexpensive the joint can be designed. On the other hand, the pretensioning methods are more expensive when the accuracy grows.

Insufficient pretensioning leads to:

• detaching of jointing surfaces under axial loads
• growth of the screw’s tensile amplitude
• fatigue of the screw
• nut loosening under vibration
• sliding of the joint because of the shearing forces

Too big pretensioning leads to:

• static overloading of the screw under load
• screw loosening under load due to plastic elongation
• breaking of the screw already in the tightening

Screw joint must retain proper pretensioning through it’s planned lifetime. Following events can cause the joint to loose it’s tightness:
• screw breaks
• thread shears
• nut unscrews
• joint parts sets
© Ferrometal 08/2015

Prestressing forces and tightening torques

Recognition of friction coefficient µ is very important to be able to determine right tightening torque. There can be considerate differences in tightening torques, depending on the surfaces, lubricants,
tightening methods and the deviations of all above. Therefore it is highly recommended to carry out practical tests to determine the right tightening torque in the applica-
tion in question. Following tables for hex head screws DIN 931 – DIN 933 and hex socket head screws DIN 912 are only
approximate!

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 carbon steel screws
M-thread Friction Max. Prestressing force (kN) Max. Tightening torque (Nm)
std pitch coefficient (90% utilisation of 0,2%-limit)
µ 5.6 8.8 10.9 12.9 5.6 8.8 10.9 12.9
0,10 2,10 4,5 6,7 7,8 1,21 2,6 3,9 4,5
M4 0,12 2,04 4,4 6,5 7,6 1,37 3,0 4,6 5,1
0,14 1,98 4,3 6,3 7,4 1,51 3,3 4,8 5,6
0,10 3,43 7,4 10,8 12,7 2,4 5,2 7,6 8,9
M5 0,12 3,33 7,2 10,6 12,4 2,7 5,9 8,6 10,0
0,14 3,23 7,0 10,3 12,0 3,0 6,5 9,5 11,2
0,10 4,84 10,4 15,3 17,9 4,1 9,0 13,2 15,4
M6 0,12 4,71 10,2 14,9 17,5 4,7 10,1 14,9 17,4
0,14 4,57 9,9 14,5 17,0 5,2 11,3 16,5 19,3
0,10 8,8 19,1 28,0 32,8 10,0 21,6 31,8 37,2
M8 0,12 8,6 18,6 27,3 32,0 11,3 24,6 36,1 42,2
0,14 8,3 18,1 26,6 31,1 12,6 27,3 40,1 46,9
0,10 14,1 30,3 44,5 52,1 20 43 63 73
M10 0,12 13,7 29,6 43,4 50,8 23 48 71 83
0,14 13,3 28,8 42,2 49,4 25 54 79 93
0,10 20,5 44,1 64,8 75,9 34 73 108 126
M12 0,12 20 43,0 63,2 74,0 39 84 123 144
0,14 19,4 41,9 61,5 72,0 43 93 137 160
0,10 28,2 60,6 88,9 104,1 55 117 172 201
M14 0,12 27,4 59,1 86,7 101,5 62 133 195 229
0,14 26,7 57,5 84,4 98,9 69 148 218 255
0,10 38,6 82,9 121,7 142,4 84 180 264 309
M16 0,12 37,6 80,9 118,8 139,0 96 206 302 354
0,14 36,6 78,8 115,7 135,4 107 230 338 395
0,10 47,1 104 149 174 117 259 369 432
M18 0,12 45,8 102 145 170 133 295 421 492
0,14 44,6 99 141 165 148 329 469 549
0,10 60,3 134 190 223 164 363 517 605
M20 0,12 58,8 130 186 217 187 415 592 692
0,14 57,2 127 181 212 209 464 661 773
0,10 75,2 166 237 277 220 495 704 824
M22 0,12 73,4 162 231 271 252 567 807 945
0,14 71,4 158 225 264 282 634 904 1057
0,10 86,9 192 274 320 282 625 890 1041
M24 0,12 84,7 188 267 313 322 714 1017 1190
0,14 82,4 183 260 305 359 798 1136 1329
0,10 114 252 359 420 414 915 1304 1526
M27 0,12 111,2 246 351 410 474 1050 1496 1750
0,14 108,3 240 342 400 530 1176 1674 1959
0,10 138,7 307 437 511 563 1246 1775 2077
M30 0,12 135,3 300 427 499 644 1420 2033 2380
0,14 131,7 292 416 487 719 1597 2274 2662
0,10 172,5 381 543 635 760 1679 2392 2799
M33 0,12 168,4 373 531 621 871 1928 2747 3214
0,14 164 363 517 605 975 2161 3078 3601
0,10 202,7 448 638 747 979 2164 3082 3607
M36 0,12 197,8 438 623 729 1121 2482 3535 4136
© Ferrometal 08/2015

0,14 192,6 427 608 711 1253 2778 3957 4631

0,10 243,1 537 765 895 1264 2791 3975 4652
M39 0,12 237,4 525 748 875 1450 3208 4569 5346
0,14 231,3 512 729 853 1624 3597 5123 5994

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 Austenitic (stainless) screws:

Max. Tightening torque

Max. Prestressing force (Nm)
Friction (kN) (90% utilisation of
M-thread 0,2%-limit)
coefficient
std pitch
µ
A2-70 A2-70
A4-80 A4-80
A4-70 A4-70

0,10 2,97 3,96 1,7 2,3

M4 0,20 2,40 3,20 2,6 3,5
0,30 1,94 2,59 3,0 4,1
0,10 4,85 6,47 3,4 4,6
M5 0,20 3,93 5,24 5,1 6,9
0,30 3,19 4,25 6,1 8,0
0,10 6,85 9,13 5,9 8,0
M6 0,20 5,54 7,39 8,8 11,8
0,30 4,49 5,98 10,4 13,9
0,10 12,60 16,70 14,5 19,3
M8 0,20 10,20 13,60 21,4 28,7
0,30 8,85 11,00 25,5 33,9
0,10 20 26,6 30 39,4
M10 0,20 16,2 21,7 44 58
0,30 13,1 17,5 51 69
0,10 29,1 38,8 50 67
M12 0,20 23,7 31,6 74 100
0,30 19,2 25,6 88 117
0,10 40 53,3 79 106
M14 0,20 32,6 43,4 119 159
0,30 26,4 35,2 141 188
0,10 55 73,3 121 161
M16 0,20 44,9 59,8 183 245
0,30 36,4 48,6 218 291
0,10 69 92 174 232
M18 0,20 56,2 74,9 260 346
0,30 45,5 60,7 308 411
0,10 88,6 118,1 224 325
M20 0,20 72,4 96,5 370 494
0,30 58,7 78,3 439 586
0,10 107 143 318 424
M22 0,20 88 118 488 650
0,30 72 96 582 776
0,10 142 165 400 534
M24 0,20 101 135 608 810
0,30 83 110 724 966

For lengths up to 8X thread diameter. Strength requirements for diameters above M24 must be agreed between the buyer and the manufacturer.

© Ferrometal 08/2015

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 Approximate values for friction coefficients of different materials, surfaces and lubricants:

Typical example
Range of friction
coefficient Material or surface Lubricant

metallic, bright-polished
solid lubricants:
phosphated
MoS2, graphite, PTFE, PA, PE, PI
galvanic coatings:
in lubricating lacquers or pastes
Zn, Zn/Fe, Zn/Ni
wax dispersions
zinc laminated coatings

metallic, bright-polished solid lubricants:

phosphated MoS2, graphite, PTFE, PA, PE, PI
0,04…0,10
galvanic coatings: in lubricating lacquers or pastes
0,08…0,16
Zn, Zn/Fe, Zn/Ni wax dispersions, greases
zinc laminated coatings oils
aluminium and manganese alloys as delivered condition

MoS2, graphite
hot dip galvanized
wax dispersions
with integrated lubricant
organic coatings
wax dispersions
solid lubricants or waxes
austenitic steel
pastes
wax dispersions
austenitic steel
pastes
metallic, bright-polished
as delivered condition (light oiled)
0,14…0,24 phosphated
galvanic coatings:
Zn, Zn/Fe, Zn/Ni none
0,20…0,35 zinc laminated coatings
austenitic steel oil
galvanic coatings:
Zn, Zn/Fe none
hot dip galvanized

galvanic coatings:
Zn/Fe, Zn/Ni
≥ 0,30 none
austenitic steel
aluminium and manganese alloys

Tightening factor αA allows errors in tightening methods and it is considerated when designing the screw joint. The greater the factor is, the
bigger the screw must be selected.

Tightening factor
Deviation Tightening method
αA

1 ± 5% …12% Yield point or rotation angle controlled tightening, power-assisted or manual

1,2…1,6 ± 9% …23% Hydraulic tightening

1,4…1,8 ± 17% …28% Torque-controlled tightening or precision tool with torque measurement
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1,7…2,5 ± 26% …43% Torque-controlled tightening using a torque wrench

2,5…4,0 ± 43% …60% Impulse-controlled tightening, impact wrench

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 Example:
From above tables, search maximum tightening torque and the corresponding maximum prestressing force for hex head screw DIN 931 8.8 ZN M16X80. Joint is assem-
bled with torque measuring precision tool and without lubricants.

1) The screw is electro zinc plated and no lubricant is used.

 Friction coefficient is 0,14…0,24. Lower value 0,14 is chosen.

2) From the carbon steel screw table, search M16 / 0,14 / 8.8
 Maximum tightening torque is 230 Nm.

3) From the same table, search maximum prestressing force.

 230 Nm results max. prestressing force 78,8 kN.

4) Prestressing force is corrected with the tightening factor αA.

 Minimum expected prestressing force is 78,8 kN / 1,6 = 49,25 kN.

Friction grip (HV) fasteners

Changeover to EN –product standards in structural fasteners

Changeover
DIN 6914 EN 14399-4
DIN 6915 EN 14399-4
DIN 6916 EN 14399-6

Washers according to DIN 6917 and DIN 6918 remain as they are defined in DIN –standards.

In joints where DIN –standardized products are specified EN products can be used since they are technically equivalent or better. This is not the case vice versa.

Ordering information

DIN

Hexagon screw DIN 6914 10.9 HOT M20X80

Hexagon nut DIN 6915 10 HOT M20
Washer DIN 6916 HOT M20 (21.0)

EN

Hexagon screw / nut assembly EN 14399-4 HV 10.9/10 HOT M16X70

Washer EN 14399-6 HOT M20 (21.0)

Deadlines for product standards

Untill September 2007, German national standards DIN 6914, DIN 6915 and DIN 6916 existed side by side with European standards EN 14399-4 and -6. After that
only products according to EN with CE –marking are allowed to be produced. HV –sets on stock according to DIN 6914 / 6915 / 6916 are allowed to be supplied and
used without any limitation in time.

Properties

HV (Hoch Vorgespannt) is the term used for steel construction joints with high tensile screws. Special requirements are set to these screws, washers and nuts since they have
to establish a safe and tested joint. They can be used only for constructions with mainly static load, such as halls, platforms and framework constructions.

The surface treatment in HV –fasteners are usually hot dip galvanizing. Zinc layer thickness is even up to 50…70 µm. This gives sufficient corrosion protection also in the
most aggressive atmospheres. Together with known surface properties and defined friction coefficient of nuts treated by MoS2, proper tightening values can be determined.
HV –fasteners are also available in plain finish.

Screw and nut set EN 14399-4 and washer EN 14399-6 form a complete set which should be delivered from the same manufacturer. Ferrometal Oy stocks a wide
© Ferrometal 08/2015

range of HV-sets produced by our high quality partner Peiner Umformtechnik GmbH.

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 Specified preloads and tightening torques for 4 tightening methods for property class 10.9 HV –assemblies:

1 2 3 4 5 6 7 8

Air driven impact

Torque control method Turn of the nut method Combined method
wrench method

Tightening torque MA Set preloading force FV5 2)

Required Pretightening torque
Screw to achieve the specified to achieve the specified Pretightening torque MVA78
preload FV MVA6 2)
diameter preload FV preload FV
in the screw
Surface treatment and lubrication

Hot Dip Galvanized As manufactured Hot Dip Galvanized As manufactured

As in column 3 or 4 2) As in column 3 or 4 2)
and lubricated 1) and slightly oiled and lubricated 1) and slightly oiled

k Nm kN Nm Nm
M12 50 100 120 60 10 75 90
M16 100 250 350 110 50 190 260
M20 160 450 600 175 50 340 450
M22 190 650 900 210 100 490 680
M24 220 800 1100 240 100 600 825
M27 290 1250 1650 320 200 940 1240
M30 350 1650 2200 390 200 1240 1650
M36 510 2800 3800 560 200 2100 2850

1) Nuts lubricated with MoS2 or equivalent lubricant

2) Independent from the lubrication on the thread and on the faces of the nut and bolt

When assembling, install a washer under each screw head and nut. Make sure that the washer’s chamfer points outwards, this way the washer can absorb the transition
radius between the shaft and the head. Screw the nut by hands before tightening it to the right torque.

Torque control method

To achieve the specified preload FV according to column 2 in above table, a torque MA shown in columns 3 & 4 (dependant on the surface treatment and lubrication of
the threads), shall be applied with measurable tightening tools. This method allows a stepwise tightening when the joint has many screws. By this method, it is possible to
continue with preloading and so to inspect the screws. Moreover, second round of tightening can be applied after couple of days to assure that the specified preload is
achieved.

Air driven impact wrench method

This method uses an air driven impact wrench for tightening of the nut. The wrench shall be set according to the column 5 to a preload FV5, which is 10% higher than for the
torque control method.

Turn of the nut method

Following condition should be fullfilled and checked before using this tightening method: all parts have to be flat and in good firm contact with each other. Tightening is
done in two steps: first apply a pretorque MVA6 according to column 6 by using some of the methods described above. In the second step, an additional rotation of nut
shall be applied. The required additional rotation angle must be determined via appropiate testing procedure on the original assembly. One option is to measure the elonga-
tion of the screw under full preload.

Combined method
Apply the pretensioning torque according to column no. 7 or 8 depending on the surface treatment. Second step is to apply additional angle of nut rotation δ according to
the table below.
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 Required additional angle of rotation δ and value of rotation V for the combined tightening method

1 2 3

Clamping length LK 1) Additional angle of

Value of rotation V
of the HV-set rotation δ

LK < 2d 45° 1/8 turn

2d ≤ LK < 6d 60° 1/6 turn

6d ≤ LK < 10d 90° 1/4 turn

10d < LK No recommendation No recommendation

1) LK = lK + 2h
lK = clamping length according to EN 14399-4
h = washer thickness according to EN 14399-6

Inspection of the specified screw preload

1 2 3

Additional angle of
Conclusion Further actions
rotation

< 30° Preload force is sufficient None

Leave the inspected assembly but

30°…60° Preload force is barely sufficient
inspect two more screws in the same connection

Replace the inspected screw by a new one 1)

> 60° Preload force is not sufficient
and inspect two more screws in the same connection

1) In case of statically loaded bearing type connection with HV- or HV fit screws without axial forces, the inspected screws may remain in the
construction.

Main dimensions for HV-fasteners

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 M12 M16 M20 M22 M24 M27 M30 M36

ds 12 16 20 22 24 27 30 36
b1 21 26 31 32 34 37 40 48
b2 23 28 33 34 37 39 42 50
c 0,6-0,2 0,6-0,2 0,8-0,4 0,8-0,4 0,8-0,4 0,8-0,4 0,8-0,4 0,8-0,4
dw (min) 20 25 30 34 39 43,5 47,5 57
e (min) 23,91 29,56 35,03 39,55 45,20 50,85 55,37 66,44
Standard clamping
k 8 10 13 14 15 17 19 23 lengths
k’ (min) 5,28 6,47 8,47 9,17 9,87 11,27 12,56 15,36
Further clamping
m 10 13 16 18 20 22 24 29
lengths
r (min) 1,2 1,2 1,5 1,5 1,5 2 2 2
s 22 27 32 36 41 46 50 60
b1 for lengths above the red line, b2 for lengths under the red line

Nominal Clamping length

length M12 M16 M20 M22 M24 M27 M30 M36
30 6 - 10
35 11 - 15 5-9
40 16 - 20 10 - 14 5-9
45 21 - 23 15 - 19 10 - 14
50 24 - 28 20 - 24 15 - 19 14 - 18 12 - 16
55 29 - 33 25 - 29 20 - 24 19 - 23 17 - 21
60 34 - 38 30 - 34 25 - 29 24 - 28 22 - 26 18 - 22
65 39 - 43 35 - 39 30 - 34 29 - 33 27 - 31 23 - 27
70 44 - 48 40 - 44 35 - 39 34 - 38 32 - 36 28 - 32 24 - 28
75 49 - 53 45 - 47 40 - 44 39 - 43 37 - 41 33 - 37 29 - 33
80 54 - 58 48 - 52 45 - 49 44 - 48 42 - 46 38 - 42 34 - 38
85 59 - 63 53 - 57 50 - 54 49 - 53 47 - 51 43 - 47 39 - 43 31 - 35
90 64 - 68 58 - 62 55 - 57 54 - 56 52 - 53 48 - 52 44 - 48 36 - 40
95 69 - 73 63 - 67 58 - 62 57 - 61 54 - 58 53 - 57 49 - 53 41 - 45
100 74 - 78 68 - 72 63 - 67 62 - 66 59 - 63 58 - 60 54 - 56 46 - 48
105 73 - 77 68 - 72 67 - 71 64 - 68 61 - 65 57 - 61 49 - 53
110 84 - 88 78 - 82 73 - 77 72 - 76 69 - 73 66 - 70 62 - 66 54 - 58
115 83 - 87 78 - 82 77 - 81 74 - 78 71 - 75 67 - 71 59 - 63
120 94 - 98 88 - 92 83 - 87 82 - 86 79 - 83 76 - 80 72 - 76 64 - 68
125 93 - 97 88 - 92 87 - 91 84 - 88 81 - 85 77 - 81 69 - 73
130 98 - 102 93 - 97 92 - 96 89 - 93 86 - 90 82 - 86 74 - 78
135 98 - 102 97 - 101 94 - 98 91 - 95 87 - 91 79 - 83
140 108 - 112 103 - 107 102 - 106 99 - 103 96 -100 92 - 96 84 - 88
145 108 - 112 107 - 111 104 - 108 101- 105 97 - 101 89 - 93
150 118 - 122 113 - 117 112 - 116 109 - 113 106 - 110 102 - 106 94 - 98
155 118 - 122 117 - 121 114 - 118 111 - 115 107 - 111 99 - 103
160 128 - 132 123 - 127 122 - 127 119 - 123 116 - 120 112 - 116 104 - 108
165 128 - 132 128 - 131 124 - 128 121 - 125 117 - 121 109 - 113
170 138 - 142 133 - 137 132 - 136 129 - 133 126 - 130 122 - 126 114 - 118
175 138 - 142 134 - 138 131 - 135 127 - 131 119 - 123
180 148 - 152 143 - 147 142 - 146 139 - 143 136 - 140 132 - 136 124 - 128
185 144 - 148 141 - 145 137 - 141 129 - 133
© Ferrometal 08/2015

190 158 - 162 153 - 157 152 - 156 149 - 153 146 - 150 142 - 146 134 - 138
195 154 - 158 151 - 155 147 - 151 139 - 143
200 168 - 172 163 - 167 162 - 166 159 - 163 156 - 160 152 - 156 144 - 148
210 178 - 182 173 - 177 172 - 176 169 - 173 166 - 170 162 - 166 154 - 158
220 188 - 192 183 - 187 182 - 186 179 -183 176 - 180 172 - 176 164 - 168
230 193 - 197 192 - 196 189 - 193 186 - 190 182 - 186 174 - 178
240 203 - 207 202 - 206 199 - 203 196 - 200 192 - 196 184 - 188
250 213 - 217 212 - 216 209 - 213 206 - 210 202 - 206 194 - 198
260 223 - 227 222 - 226 219 - 223 216 - 220 212 - 216 204 - 208

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 Securing screw joint can be done with different products and methods:

1. Mechanical components, such as locking wires, locking washers, spring or tooth washers, flanged / serrated screws or nuts.
2. Locking nuts (Nyloc-nuts). Heat resistance up to 120°C / 170°C. Recommended to be replaced after five unscrewing.
3. Thread forming screws. Because of high friction and small tolerance, they do not loose easily.
4. Special products, like Nordlock –locking washers or thread locking glues.

When designing a screw joint, galvanic corrosion (contact corrosion) must be taken into account. It occurs when jointing elements have a electrochemical potential differ-
ence and huidity acts as a electrolyte. In order to avoid galvanic corrosion, suitable and not suitable materials and surfaces are presented in table below.

Structure

Steel, yellow passivated

Steel, black passivated
material

Steel, zinc plated

Steel, plain
Aluminium
A2 / A4

Copper

Brass
Fastener
material

A2 / A4 +++ +++ ++ ++ ++ ++ ++ ++

Aluminium ++ +++ ++ ++ + + + +

Copper + + +++ ++ + + + +

Brass + + ++ +++ + + + +

Steel, black passivated - - - - +++ ++ ++ +

Steel, yellow passivated -- -- -- -- + +++ ++ +

Steel, zinc plated -- -- -- -- + + +++ +

Steel, plain --- --- --- --- -- -- -- +++

+++ = recommended combination

- - - = not recommended combination
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 8. Self drilling screw
DESIGN AND INSTALLATION INSTRUCTIONS

Useful lengths L1 and L2: Installing to steel basematerials

L1 is the maximum overall thickness of materials to be fixed
L2 is the length of the unthreaded part of the screw
L1 and L2 can be found from the technical information tables
The first two threads cut the spiral to the steel, and might therefore be reshaped.
They are not considered to be included to the useful length measures.

Useful lengths L1 and L2: Installing to wooden basematerial

L1 selection criteria:
Either the installation depth to wooden basematerial must be minimum 23 mm or L1=thickness of the
wooden material

Effective drilling thickness M

Drilpoint must penetrate the material before it starts the threading.
This is why the recommended maximum thickness should not be exceeded.
Possible empty space between materials is as well considered as part of
the effective drilling thickness M. If going under recommended minimum
thickness, joint-strength and sealing capacity will decrease.

Installation
It is recommended to use electrical screw driver with torque release or depth gauge. TURNINGTURNING
FORCE FORCE
Axial force need is 10-20 kp.
MOUNTING FORCE FORCE
MOUNTING

AXIAL FORCE
AXIAL FORCE

Rotation speeds for screws (unloaded)

Diameters 3,5-4,8 mm 1700-2500 rpm
Diameters 5,5-6,3 mm 1200-1800 rpm

Right tension – EPDM-insulation shown approx

1 mm under washer
Too loose Right tension Too tight

Screws must set in to the basematerial within 90 degree angle. Too loose Right tension Too tight
When there will be small deflections with installation angle in
practise, the best joint-strength and sealing capacity will be Löysä Oikein Kireä
achieved with a detachable washer.

PIAS/PIASTA drillpoints drill down easier in a right angle,

than a self drilling screw with a spoonlike drillpoint.
Löysä Oikein Kireä
Löysä Oikein Kireä
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 Headmarking Sinkitty hiiliteräs Ruostumaton A2
Headmarking enables screw type identification
Pias Piast a
after installation
Electro
Sinkittyzinc plated A2
hiiliteräs stainless steel
Ruostumaton A2
carbonPiassteel Piasta
Piast a A2
Sinkitty hiiliteräs Ruostumaton
Pias
Pias Piast a
Piasta; genuine A2-stainless steel
The corrosion resistance of a A2-stainless steel is remarkably good, but it is impossible to 2
harden it. The drillpoint and the first two cutting threads of a Piasta screw, 1) are hardened 22
carbon steel.
The head and the rod, which submit to load and corrosion, 2) are A2-stainless steel. The 2
whole Piasta screw has Ruspert-cover to protect from corrosion and to reduce friction
when installing. 11 1
1
Painted screws
Standard colours are RR- and RAL-shades.
Paint thickness is minimum 40 µm.
Screws with washers, the washer is also painted from
the top and sides. The paint surface tolerates installation and normal stress of usage.

Corrosion resistance
In additional to the environment conditions, things that
effect the development of corrosion:

Microclimate, which can differ from the general surrounding climate. The ventilation of
structures, which effects the microclimate

Galvanic corrosion eats the less electronegative metal in the pair.

The potential difference and mass index between metals, effects the
corrode-speed. The mass of a screw is always only a friction of the mass of the whole
structure. To secure a long life time, screw should always be more noble metal than the
structure’s metal is.
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 9. Fixcon concrete screw

Easy to install
Hexagon head together with Torx drive gives flexibility and makes installation easier.
Screw’s dimensions are stamped into the head where from they can be easily checked
even after installation.

Number of tools needed for the installation process is less as the same wrench size is
used in both 7,5 mm and 10 mm screws.

Flange head makes it even more easier

Hexagon head together with flange do not require separate washer to be used. Flange
also protects fixture’s surface from scratching when the screw is tightened and gives
extra grip as socket tool can be pushed against it.

High class material

Through suitable material selection and controlled heat treatment, FIXCON Concrete
screw gains strength that does not fail under toughest loads.

Optimum thread design

Thread design has been developed to give exceptional performance for pull-out values
yet retaining easiness of installation.

Cutting edge technology

Hardened and toothed screw tip cuts tight and firm thread groove into the concrete.
Even when passing by an ironbound.
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 Installation

1. Drill a hole with right diameter and depth into the base material.

2. Clean the hole carefully.

3. Drive the FIXCON concrete screw firmly in without impact motion.

Do not exceed the maximum tightening torque.

4. Installation is ready.
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 Drilling Installation Anchor
Size

d0 h1 (min) hinst (min) Tinst (max) L tfix (max) SW df dc

6X35 50 35 5

6X50 65 50 20

6X80 95 80 50 SW 8
5 30 12 Nm 10,5 9
TX25
6X50 c-sunk. 65 50 20

6X100 c-sunk. 115 100 70

7,5X40 55 40 10

7,5X50 65 50 20

7,5X60 75 20 Nm 60 30 SW 13
6 30 16,5 9
7,5X80 95 80 50 TX40

7,5X100 115 100 70

7,5X120 135 120 90

10X60 80 60 20

10X80 8 100 40 Nm 80 40 SW 13
40 17,5 12
10X100 120 100 60 TX40

10X120 140 120 80

L d0 Drill hole diameter

h1 Drill hole depth

dc SW hinst Min. installation depth

Tinst Installation torque

d0 df Tinst L Screw anchor length

tfix Fixture thickness

SW Drive size

df Flange diameter

dc Fixture’s clearance hole

Installation depth hinst Average load Fmax Characteristic load Fk Permitted load Fsall
Anchor size [dXL]
[mm] [kN] [kN] [kN]

7,5X50 30 7,3 4,5 1,4

7,5X100 45 15,0 10,1 3,1
Tension load
10X60 40 12,7 8,9 2,7
10X120 60 23,6 18,2 5,6
7,5X50 45 14,9 13,3 4,1
7,5X100 55 15,2 9,8 3,0
Shear load
10X60 45 27,7 21,4 6,6
© Ferrometal 08/2015

10X120 65 27,9 22,4 6,9

The values informed are based on tests carried out by Tampere University of Technology. The concrete of nominal strength K30 was used as a base material. Characteristic
load Fk is defined according to SFS EN 1990 appendix D. Permitted load Fsall have been defined with total safety factor of 3,22 which consist of partial safety factor of
2,3 for the concrete material and partial safety factor of 1,4 for the load type (½ constant and ½ changing load).

Whenever the fixing parameters are changed from the informed test arrangements, the permitted load must be defined accordingly.

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 10. SB structural bolting assembly

General about Eurocode 3

EN 1993 (Eurocode 3:n) brings changes also to the fasteners used in steel structure building. Fasteners used have to be according to European product standards. Hot Dip
Galvanization shall be done according to EN 10684. If special fasteners are used their technical properties and required tests have to be displayed.

Standard fasteners in steel structure building engineered according to EN 1993 and executed according to EN 1090-2 can be divided into two categories in the future:

• Preloaded friction grip joints where bolting assemblies EN 14399 are required to be used. These items have been available in the markets al
ready for few years and they are also belonging to Ferrometal’s delivery program. These assemblies are also known as HV –sets in spoken language.

• For non-preloaded joints, a new standard EN 15048 is introduced. These bolting assemblies are currently hard to source in the markets.
Ferrometal will be the first Finnish fastener distributor to ramp up an extensive stock range in the spring 2011.

EN 1993 (Eurocode 3) Design of steel structures

EN 1090-2 Execution of steel structures and aluminium structures

EN 14399 High-strength structural bolting assemblies for

preloading.

EN 15048 Non-preloaded structural bolting assemblies

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 General about 15048-1

Majority of the screw joints in steel structures bears only static shear forces or just mounts the elements in place. In these kind of joints pre-loading does not give any advan-
tage in technical or in economical means.

So far non-preloaded joints have been manufactured with DIN 931 or DIN 79990 hexagon head screws and DIN 934 hexagon nuts. Approvals have been national ap-
provals from the steel structure associations and inspection reports EN 10204 3.1 from the fastener manufacturers.

In the non-preloaded joints of steel structures executed acc. to EN 1090-2, the bolting assemblies must be according to the new standard EN 15048-1. In these joints HV or
TCB assemblies (please see description later on) acc. to EN 14399 can be used.

Bolting assembly means screw, nut and washer(s) if such are needed.

EN 15048-1 requirements

EN 15048-1 is not a product standard. It defines the technical requirements for the fasteners in this assembly:

• Recognised property classes: 4.6, 4.8, 5.6, 5.8, 6.8, 8.8 and 10.9. Of which 8.8 will be the class for the stock range.
• Stainless steels A2 and A4, possible property classes are 50, 70 and 80.
• Fastener diameters M12… M36.

Bolting assembly must be supplied by one and the same CE –certified manufacturer.
Products must be CE –marked although marking just in the packing is sufficient.
Enclosed is an example of a CE –marking attached into the box. Manufacturer’s production
batch identification number shall be marked since full traceability is mandatory.

In addition to the familiar property class and manufacturer’s identification marking,

every single screw and nut have to be marked ”SB” which comes from the words
Structural Bolting. Enclosed is an example of the head marks in SB sets.

The usage of SB –sets

According to the requirements of EN 15048, the components of the bolting assembly must conform to European product standards. In practical, the assemblies that Fer-
rometal stocks consists of hexagon head screws EN ISO 4014 and hexagon nuts EN ISO 4032.

Dimensional differences to the previously used DIN 931 screws and DIN 934 nuts are: Across flats size in M12 screws and nuts, the nut height in all sizes from M12 to
M36.

The screw length must be chosen so that after tightening the screw’s tip must penetrate minimum one full thread out of the nut’s bearing face. On the other hand, between
nut’s bearing face and the thread run out there must be also minimum of one full thread before the screw’s shank starts. Nuts are required to be installed so that the stamp-
ings can be inspected afterwards. Washers are not required to be used in these joints excluding single lap joints with only one screw or with single row of screws.

Since SB screw assemblies are not intended to be preloaded, from standards cannot be found any instructions for the tightening torque that shall be applied into the screw
joint. However, the structures have to be fastened tightly together. The only referral to this matter is can be found from EN 1090-2 where from direct citation is: “Every bolting
assembly must be brought into at least tight tension. This can be achieved when the
© Ferrometal 08/2015

assembler uses regular size wrench without any extensions or when the impacting torque wrench starts to hammer.”

Overtightening must be avoided, especially in case of diameter M12 and in short screws.

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 11. TCB – Tension Control Bolts: lowest cost method for pre-loaded joints

TCB complies to the latest norms of steel structure engineering

TCB is a fastening solution according to the Eurocode system for pre-loaded high friction grip joints (EN 14399-10). TCBs complies to the requirements of property class
10.9 / 10 and the minimum values of preload defined in EN 1090-2 are achieved. This means that they are interchangeable with other fastening systems.

Fp,C values [kN]

Property Screw diameter (mm)

class 12 16 20 22 24 27 30 36
8.8 47 88 137 170 198 257 314 458
10.9 59 110 172 212 247 321 393 572

Here are few examples of the many applications for TCB system:

Bridges Stadiums Railway structures

Steel structures Rivet replacements Highway gantries

TCBs can be used also in joints where only shearing forces exists. In these cases the undeniable advantage is the speed of installation achieved by the use of TCB system.
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 Advanced technology in installing and tightening

1. Slide the inner socket over the bolt spline and the outer socket
over the nut.

2. Switch the wrench on. The outer socket will rotate and tighten
the nut untill the bolt reaches the required tension. After this the
outer socket will stop rotating and the inner socket will rotate in the
opposite direction and shear the spline off.

3. When the spline has sheared off pull back on the wrench until
the outer socket is no longer engaging the nut. The installation is
ready and in right tension.

4. The bolt spline is retained by the wrench and can be discarded

by engaging the small trigger on the wrench handle.
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 TCB is extremely quick, easy and safe to install. One man can
install and tighten the joint. Visual inspection can be easily done to
check whether the joint has been manufactured or not.

With one shear wrench several dimensions can be installed just by

changing the socket of a right size.

For limited space installation there are available sophisticated tools

to complete the job. With non impacting electrical shear wrenches
there is no risk for hand-arm vibration syndrome.

With TCBs, consistent tension is achieved in the joint which do not

loosen with vibration. No additional locking elements are needed.

There is no risk of bolt relaxation since no torsional shear is

induced during tightening

Add to grip lenght

Nominal thread size Determination of bolt length is done from the enclosed table.
=> bolt lenght
mm inch mm inch
M12 - 20 -
M16 5/8” 25 1”
M20 3/4” 30 1 1/4”
M22 7/8” 35 1 1/4”
M24 1” 40 1 1/2”
M27 1 1/8” 45 1 3/4”
M30 1 1/4” 50 2”

High performance yet environment friendly Greenkote coating

Greenkote is a new innovative diffusion coating developed for the corrosion protection of TCBs. The process is a thermochemical surface
modification and can be used for various metals, alloys, sintered ferrous-based materials, grey iron and cast iron.
 Totally environment friendly.
 Salt spray resistance up to 1200 hours.
 No risk of hydrogen embrittlement.
 Long-term corrosion protection up to 400 °C.
 Coating thickness uniformity +/- 5 microns.
 Excellent preparation for painting.
 Greenkote does not include forbidden chrome VI or chrome III particles.
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 12.

Aerated con- Plaster-

Concrete Solid brick Hollow brick Natural stone crete Light grovel board

S-KA

Multi-
Monti

LA, LAH

MTA

PFG

Voima-
ankkuri B/S

MSA

PKN

CONFIX

KRH

NAT, NAT L

SUP,
SUF

LYT

KBT

KBTM
© Ferrometal 08/2015

KEM
KEMLA

ITH

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 Aerated con- Plaster-
Concrete Solid brick Hollow brick Natural stone crete Light grovel board

KLA

OLA

MOLA

YLT

CONCRETE
The most common building material. Concrete is mainly used in industrial building because of it’s high strength. In housebuilding typical concrete structures are
foundations, supporting structures, midsoles and stair elements. All expanding anchors as well as chemical anchors are suitable for use in concrete. Restrictions
of use are spacings and edge distances.

SOLID BRICK
A very common building material. Brick is used mainly in small house building. In industrial building brick is mainly used as material of separating structures.
All expanding anchors are suitable for using in brick. Restrictions of use are spacings, edge distances and sizes of fixings

HOLLOW BRICK
A very common building material. Hollow brick is mainly used as material for separating structures, and in constructions where some kind of thermal isolation
is required. Suitable anchors for hollow brick are Nylon plugs made with long expanding zone as well as injection resins used with a sleeve. Restrictions of
use are same as in solid brick.

NATURAL STONE
Main use in buidings is in covering surfaces like facades and fl oors. Most expanding anchors as well as chemical anchors are suitable for use in natural
stone. Restrictions of use are spacings and edge distances. Because of brittleness, stone cracks easily.

AERATED CONCRETE
A rather common building material in all building because of it’s light weight and fl exibility in use. Aerated concrete is used mostly in separating structures,
but also in supporting structures. Suitable anchors for aerated concrete are Nylon plugs with long expansion zone and those, specially designes for this mate-
rial, like KBT. Chemical fi xings can be used with resticions (special shape of the hole).

LIGHT GRAVEL
A common building material in small house building. It is mainly used in foundations and supporting structures. Suitable anchors for this material are Nylon
plugs with long expanding zone. Chemical fi xings can be used with resticions (special shape of the hole).

PLASTERBOARD
A very common building material in all building. Main use of this material is in surface structures. Suitable fi xings are hollow wall and cavity anchors.

MATTERS TO BE OBSERVED WHEN INSTALLING AN ANCHOR

1. Enough strength in the base material (concrete >C20/25). Base material’s strength has a remarkable infl uence in the capacity of an anchor.
2. Right size of the hole. Anchors do not fi t in too small holes and they do not work properly, or at all in too big holes.
3. Embedment depth according to instructions. Embedment depth has a remarkable influence in the capacity of an anchor.
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 CE-MARKING AND ETA APPROVAL
WE HAVE THEM!
Sormat products have several national and international approvals of which the most important is the certifi ed proof of conformity, CE-certificate, based on the European
Technical Approval ETA.

A right to use CE marking requires a European Technical Approval, ETA. Opposite to the CE marking, the ETA is not well known, not even among professionals. One of the
reasons is, that the ETA for metallic anchors consists of 12 alternative options. Each option consists of different amount of tests to be performed to the product. In option 1,
a lot of different properties of the product is tested, as in option 12 just a few properties will be tested. This all means that a product in option 1 has got much more official
data of its properties than the one in option 12. However, amount of data does not make a product better, it only provides a possibility to study somewhat versatile applica-
tions.

According to the Quality Policy of Sormat, the products must fulfil customer needs, as well as self evident needs like the needs of authorities. This is why we take care that
the essential products in our range will have a CE marking. When choosing a Sormat product, as a retailer or as an end user, You can be sure about conformity, safety, and
suitability of the product also in most demanding applications.

Certificate number

Directive that the certificate is based on

Identification of certificate approving body

0809 - CPD - 0609

Approval criteria and application area

Approval number

Sormat chemical solutions

Sormat offers a wide range of chemical anchoring solutions for the building and construction industry. These resin-based systems can be used to fix a wide variety of compo-
nents and fixtures directly to different base materials. Each system has been designed to meet the high performance standards of the construction industry and is manufac-
tured within the internationally recognized ISO 9001:2000 Quality System.

Sormat comprehensive chemical anchoring solutions consists of two different kind of anchoring methods and a large variety of accessories. Sormat ITH resins are 2-com-
ponet, solid plastic cartridge based, fast curing injection resins systems for chemical fastenings and Sormat
KEM/KEMLA are factory premeasured and sealed glass capsule anchors.

In general chemical anchoring solutions have additional benefits in applications which require egg. small edge distances and anchor spacing, dynamic load values and
flexibility related to different base material variatons.
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 Determing the right anchoring method

The functioning of all types of chemical anchors is based on the adhesion of the resin to the wall of the bore hole and the threaded rod/rebar. It is of the utmost importance
to comprehend the difference between the various Sormat anchoring solutions (see next pages) available and other factors related to the installation. When determining the
right anchoring solution understanding of the application requirements is necessary, for example:

• dynamic
LOAD REQUIREMENTS
• static
• design, etc
• hard concrete (C50/60)
BASE MATERIAL • soft concrete (C20/25)
• cracked concrete
• masonry
• anchor spacing
INSTALLATION DIMENSIONS • edge distances
• embedment depth
APPLICATION- AND ENVIRONMENTAL CRITERIA• corrosion resistance
• fire resistance requirements
• earthquakes
• extreme weather conditions
• anchoring in wet or damp holes

Product Recommended Concrete Solid brick Hollow brick Natural stone Aerated
tension load KG concrete

Performance M16
stud concrete
C20/25

ITH 150 P 1980

++ +++ +++ ++ +++

ITH 300 P 1980 ++ +++ +++ ++ +++

ITH 380 P 1980 ++ +++ +++ ++ ++

ITH 300 EA +++ + + +++ -

2030

ITH 380 EA +++ + + +++ -

2030

ITH 380 +++ + + +++ -

2480

ITH 380 W +++ + + +++ -

2030

ITH 400 EPOX +++ - - +++ -

3880

KEM 1500
+++ - - +++ -
© Ferrometal 08/2015

KEM VE +++ - - +++ -

2220

KEMLA 1190 +++ - - +++ -

+ mild suitability ++ average suitability +++ high suitability -not suitable

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 Product Base material Dispencing tool possible Other features
temperature applications

+25°C - +25°C silicone IPU 380 IPU 400 no rebar under heat resistance ETA- styrene shelf life
dispencer dispencer water up to approved free (months)
-6°C-
120°C
-5°C +5°C
-18°C

18
ITH 150 P

18
ITH 300 P

18
ITH 380 P

18
ITH 300 EA

18
ITH 380 EA

18
ITH 380

18
ITH 380 W

18
ITH 400 EPOX

36
KEM

36
KEM VE

12
KEMLA

Suitable for mentioned application or conditions

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 Introducing the Sormat MULTI-MONTI®

Sormat Multi-Monti® is an innovative anchorage system for fixation in concrete and brick. The Sormat Multi-Monti® Screw-In-Anchor will be screwed directly into a pre-
drilled hole. The holding principle is based on the multiple chisels in the tip of the screw anchor that cut in to the concrete.

The formclosed anchorage is free of expansion forces and can be loaded immediately. No defi ned torque is required for a safe connection. Sormat Multi-Monti® can be
used for anchoring in concrete and other solid wall materials such as sand lime brick,
solid-brick, clinker, and even in hollow concrete slabs.

New features, new advantages!

Sormat MULTI-MONTI® in a truly innovative product for fi xation into concrete and brick. Its advantages range from ETA approved quality to easy installation and secure
fixing. Here are listed some of these features and be

FIRST SCREW ANCHOR WITH ETA APPROVAL

• high quality and safety quarantee
• the product can be used with complete safety even in critical installation conditions (approved for cracked and non-cracked

INSTALLATION WITHOUT ANY PRESCRIBED STAINLESS STEEL

TIGHTENING TORQUES • suited to use in tunnel applications
• installation errors are effectively ruled out, which is an – wide range of applications possible
additional safety factor
• the ability to work without a torque wrench
FASTENING WHICH IS FREE OF EXPANSION PRESSURE REMOVABLE AND REUSABLE
• the ability to work close to the edge of the base material • the anchor can be completely removed if needed
• small spacing and edge distances • the anchor can be reused two times, which saves temporary
fastening costs
THE SCREW IN ANCHORS IS SET WITHOUT A PLUG NO PROTRUDING THREADS
• quick and easy to install • neat head finish
• reduced installation time
CHISELD TIP DESIGN IMMEDIATE LOADING
• the thread starts immediately without breakout of the • no waste of time, the anchor will bear loads immediately
concrete surface

Suitable base materials

The Sormat MULTI-MONTI® is approved for installations in cracked and non-cracked concrete and is suitable for use with many other building materials as well.

Concrete Natural stone Solid brick Sand lime brick Hollow con-
crete slabs
Applications

There are many different versions of Sormat MULTI-MONTI® Screw-In-Anchor available. Be it external or internal use, or structures subject to obligatory fireproofing:
Sormat MULTI-MONTI® covers most areas of use. Here is a selection of the most common applications

Fastening of fences, Seating Racking / shelving Beams and Protection barriers

railings / handrails installation structures etc.
© Ferrometal 08/2015

Scaffolding Suited for use in tun- Baseplates Suspended Other applications

nel construction (fire ceilings such as illuminated
prevention plates) signs concrete form-
work and temporary
fastenings

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 13. Rivets

Riveting is very reliable and widely used technique for fastening materials together permanently.
For best results following instructions should be observed:

Joint strength
Determine the shearing and tensile strengths that are required for the joint. They are fullfilled by using adequate number of rivets with right sizes and materials

Workpiece materials
When joining materials with different thickness or strengths the stronger material must be on the blind side of the joint. For example when fastening plastic and steel
together the plastic piece should be under the rivet head and the steel on the blind side.

Rivet diameter
In heavy load applications the rivet diameter should be at least equal to the thickest sheet thickness but not more than 3X the sheet under the rivet head.

Rivet length
Recommended length is the same as thickness of the workpiece materials (S) added by the rivet diameter (d). L = S + d

Grip range S (min-max)

The maximum thickness of the jointing workpieces when the hole diamater is according to the given values. The possible gap between the sheets must be included in the
grip range calculation.

Hole diameter
Drilled or punched holes must be free of burrs in order to achieve reliable joint. In many cases the rivet fixes well into a hole which is maximum 0,1 mm bigger than the
rivet’s nominal diameter.

Edge distance
Rivet hole distance from an edge should be at least 2X rivet diameter but not more than 24X.

Rivet distance
In high strength joints the distance between rivets should not be more than 3X rivet diameter.

Rivet material
The right rivet material is typically chosen to achieve the required strength in the joint. If the chosen rivet material differs from the workpiece material it is important to
notice the risk of galvanic corrosion.

Blind rivet types and use

Open type rivet

Vast range of blind rivets with different materials and head types.
Offers economical solution for applications which are not under heavy loads.

Closed type rivet

Blind rivets for applications in which water or pressure tightness is required or where mandrel loosening
is not allowed.

Multi-grip rivet
This rivet is suitable for joints with wider grip range than conventional rivets.
Good choice also for riveting irregular holes.

Grooved rivet
Designed for soft and fibrous materials like wood and plastic.
© Ferrometal 10/2014
© Ferrometal 08/2015

Material fibres penetrates into the grooves when the joint is manufactured.

Peel type rivet

Rivet is ideal for fibre glass, plastic, rubber, wood and laminate joints.
Applicable also for joints with oversize holes or misaligned work pieces.

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 Head types

Dome head
Typical head type which can be used in majority of the applications.

Large flange
For applications where soft, thin or brittle material is fixed into a solid base.
Large flange enables bigger hole under the head.

Countersunk
To be used when flush surface is needed.

Blind rivet parts 1 Body

2 Head
4 3 Mandrel
4 Mandrel tip
5 Mandrel beveled tip

1 3 5
2

Dimensions d Nominal diameter

with + / - tolerance

d dm L Body length
D with + / - tolerance
L P
D Head diameter
k
with + / - tolerance

k Head height
with + / - tolerance

P Mandrel length

dm Mandrel nominal diameter

Helps to choose right nosepiece for the rivet tool.
Nosepiece is crucial factor in succeeded jointing.

Rivet body d Nominal diameter

L Length
k D Head diameter
s k Head height
s Body material thickness
D d

L
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 Mandrel Mh Mandrel tip diameter
Ml Mandrel length
Me Mc F Body locking into the mandrel
dm Mandrel diameter
Me Mandrel beveled tip
Mh
Mc Mandrel breaking zone
dm F

Finished rivet d2 Expansed rivet body

D Head diameter
Sh- shearing force S Grip range
Sh Shearing force
Te Tensile force
Shear and tensile strength defines the rivet properrties
Actual strength is dependable of the joint materials and their thickness
Unit for shear and tensile force is Newton (1 kg ≈ 10N)
D d2

s
Te- tencile force

Application examples

soft
hard
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 Rivet nuts

FM blind rivet nut is an excellent solution for sheet metals where high load bearing capacity is required. Installation can be done blind (one sided) in applications where
there is no or little access at the rear e.g. beams, pipes, profiles… FM blind rivet nut portfolio covers a wide range of items for different materials, sizes and grip ranges.
Thread sizes from M3 to M12 and materials steel, A2, A4,
aluminium and brass, zinc plating Cr6 free.

Examples of different industrial applications: automotive, aviation, shipbuilding, railroads, electronics, lightning, household furniture, household electronics, buildings etc…

1 Designation
7
2 1 Fastening screw
2 Element to be fastened
3 One or several sheet(s) to be fastened
4 Deformation zone
5 Chamfer guides the rivet nut into the hole
6 3 6 Sheet thickness
7 Rivet nut head

Installation
A

A Locking nut
B
B Anvil
C
C Blind rivet nut
±1 D Mandrel
mm
D

D
Screw the FM blind rivet nut on the mandrel so that the
B mandrel protrudes about 1 mm out of the rivet nut. Push
the rivet nut into the hole of the workpiece.

D
B The setting tool will pull the FM blind rivet nut in place
by
creating the deformation chamber on the underside of
the workpiece.
Unscrew the mandrel from the rivet nut.

Fix the fastening element with applicable screw.

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 Application examples
© Ferrometal 10/2014
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© Ferrometal
© 10/2014
Ferrometal 08/2015

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