~~l~ Designation:

METRIC
F 835M - 98

Standard Specification for

Alloy Steel Socket Button and Flat Countersunk Head Cap
Screws [Metric]'
'This sumdard ;$ iS$Ued under the fixed Ik$ignalion F 835M; !he number immediately fol lowing the designation indiCales the ~ar of
original adop(ion or, in the cue of re~i $ion. the year of lasl revision. A numbcT in pamuhesc:s indicates the year o f last l'eapptO,·al . A
superscripl epsilon (0;) indiCllla an editorial clwlge &i na the last revision or reawo"al.

This standard has bun appro..,d f or IW: by ag""ciu of IM iRpanrM'" of DqtfIH.

1. Scope * ANSVASME BI8.3.4M Hexagon Socket Button Head Cap

1.1 This specification covers the requirements for quenched Screws6
and tempered alloy steel hexagon socket button (SBHCS) and ANSVASME BI8.3.5M Hexagon Socket Flat Countersun k
flat countersunk (SFHCS) head cap screws M3 throug h M20 Head Cap Screws6
thread sizes having material properties of ISO 898/1 Property 2.3 ISO Standard:
Class 12.9. 898/ 1 Mechanical Properties o f Fasteners, Boits, Screws
1.2 Fasteners meeting this spec ification are intended for and Studs6
shear type applications and have te nsile requirements equiva-
3. Ordering Information
lent to ISO 898/1 Property Class 10.9.
1.3 The hazard statement pertains only to the test method 3.1 O rders for material under this specification shal1 in -
scction, Section 11 of this specification. This standard does IIot clude:
purport 10 address all of the safety problems. if any. associated 3.1.1 Quandty (number of screws).
II';/h ;ts use. It ;s the responsibility of the !Iser of this stalldard 3. 1.2 Dimensions, including nominal thread designation,
to establish OPIJropriote safety and health prac/ices and thread pitch and nominal screw length (millimetres). A stan-
de/eml;ne the applicability of reguJa/ory limitations prior to dard pan number may be used for this defini tion.
use. 3. 1.3 Name of the screw: SBHCS o r SFHCS .
3.1.4 Coating. if required. If a protective fini sh other than
2. Referenced Documents black oxide is required, it must be specified on the order or
2.1 ASTM Standards: product standard.
A 75 1 Test Methods, Practices, and Termino logy for 3. 1.5 Lot testing, if required (see 10. 3).
Chemical Analysis of Steel Products 2 3. 1.6 Certification, if required (see 14.1 ).
D 395 1 Practice for Commercial Packaging) 3. 1.7 ASTM designation and year o f issue. and
E 3 Methods of Preparation of Metallographic Specimens 4 3. 1.8 Any special requirements.
E 18 Test Methods for Rockwell Hardness and Rockwell 3.2 Example- I000 pieces M6 X I X 25 SB HCS lo t tensile
Superficial Hardness of Metallic Materials" test, ASTM F 835M - Xx.
E 11 2 Test Methods for Detennining Average G rain Size"
4. Materials and Manufacture
E 384 Test Method for Microhardness of Materials"
F 606M Test Methods fo r Determining the Mechanical 4.1 The screws shall be fabricated from alloy steel made to
Properties of Externally and Intcrnally Thrcaded Fasteners, fine grain practice. III the event of controversy over grain size,
Washers, and Ri vets \Metricj$ referee tests on fi nished screws conducted in accordance with
F 788fF 788M Specification for Surface Discontinuities of Test Methods E 112 shall prevail.
BoilS, Screws, and Studs. Inch and Metric Scricss 4.2 Screws shall be cold upset or extruded, or both.
2.2 ANSI/ASME Standards: 4.3 Screws shall be ro ll threaded.
4.4 Screws shall be heat treated by quenching in o il from
above the transfonnation temperature and then tempering by
IThis specification is umkr" the jurisdiCtion or ASTM Conuni uec F. 16 on reheating to at least 380°C to be within the hardness range
Fasl~ners and is (be dim:t ~pon~ibitiIY or Subcommi uQc: F 16.02 on Steel Bolts. specified in Table I .
Nuts. Ri ,'CIS. and Washers.
Cw-n:1II edition apprm'ed April to. 1998. PubliWd J ul y 1998. Orig inally
4.4.1 The minimum tempering temperature may be verified
publ iShed as F 835M- 83. U5t llR'~ious edilion F 83SM- 97. by submitting screws to 370°C for 30 min at te mperature. The
1 A"""'" 8 00k of ASTM Slam/mm. Vot 0 1.03.
l A"""'" &ok ofASTM SranJanb. VoI t5.09 .
.. A"""'" Book of ASTM SuurJ4nb. \bI 03.01. • Avaitabl~ rrom American National Standards I r1$Iitu~. I1 W. 4200 SL. 13th
~ A""YDl BOtJk of ASTM Sland/,rris. VoI 15.08. Root". New York, NY 10036.

• A Summary or Cha ngl'lii seclion appears allhe fnd or Ihis slandard.

242
 ~t F 835M
TABLE 1 Mechanical Requirements TABLE 3 Minimum Ultimate Ten sile Load s

NOTE I - All values are rounded to 3 significant digits.

Full-size Screws:
Tensile, min. MPa 980
Machined Test Specimen: Tensile Load. min.
Thread Size Slress Area. mm'
Yield slrenglh a\ 0.2 % offset. min. MPa "'0 .N'
Tensile strength. min. MPa 1220 M3 X 0.5 5.03 4.93
Elongation in 50. min. % 8 M4 x 0.7 8.78 8.60
RedllClion 01 area, min, % 35 MS x 0.8 14.2 13.9
Prodl.lCl HardneS$: M6 x I 20.1 19.7
Rockwell 38 to 44 HRC M8 x 1.25 36.6 35.'
Vickars 372 to 434 OPH MIO x 1.5 58.0 56.8
MI2 x 1.75 ".3 82.6
MI4 x 2 115 ",
average cross section hardness of three readings on the screw MI6 x 2
M20 x 2.5 ,,,
'" '55
before and after rctempering shall not differ by morc than 20
DPH.
'"
A Because of the head critical coofiguratiOfl of these parts. the full·size tensile

loads are based on 80 % of the machined specimen tensiJe strength and the
4.5 When protective or decorative coatings are applied to applicable stress areas. (Loads based on 980 MPa).
the screws, precautions as required by the coating, shall be
taken to prevent embrinlement . dard round machined specimens may be used which shall meet
the " machined test specimen tensile properties" in Table I. If
5. Chemical Composition discrepancy between full-size and machined specimen res ulls,
5. 1 The chemical composition of the screw material shall full-s ize tests shall be used as the referee method to determine
canfonn to the heat analysis specified in Table 2. acceptance.
5.2 One or morc of the following alloying elements, chro- 6.4 Screws that are too short (lengths less than that specified
mium. nickel, molybdenum, or vanadium. shall be present in in 6.2 (see also Test Methods F 606M) or that have insufficient
the steel in sufficient q uantity to assure the specific strength threads for tension testing shall not be subject to tension lests
properties are met after o il quenching and tempering. The steel but shall conform to the hardness (minimum and maximum)
shall meet the AISl definition of alloy steel. that is. maximum requirements of Table I.
and minimum e lement content requirement or minimum ele- 6.5 All screws, regardless of size, shall conform to the
ment limits specifi ed. hardness specified in Table I . Hardness shall be met anywhere
5.3 Steel to which bismuth, selenium, tellurium, or lead has on the cross section through the threaded portion one diameter
been added intentionally shall not be permitted. from the screw point.
5.4 Material analysis may be made by the purchaser from
7. Other Requirements
fi nished products and the chemical composition thus deter-
mined shall conform to the requirements specified for the 7.1 Decarburiwrioll:
product analysis in Table 2. 7.1. I There shall be no evidence of carburization or gross
decarburization on the surfaces of the heat-treated screws when
6. Mechanica l Properties measured in accordance with 1[ .5.
6. J The finished screws shall conform to the mechanical 7. 1.2 The depth of partial decarburization shall be limited 10
req uirements specified in Table I . the values in Table 4 when measured as shown in Fig. I, and
6.2 Screws having a nominal thread diameter-length com- in accordance with 11.5.
bination equal to or greater than that in Table I of Test Methods 7.2 Embrittlemelll-Coatcd screws shall withstand the em-
F 606M shall be tested fu ll size and shall confoml to the full brittlement test for 24 h in accordance with 11.4 without
size tensile requirements specified in Table 3. Tensile failures showing indications of discontinuities. The loading shall be
through the head are acceptable provided the load requirements calculated with minimum screw tensile requirements.
are satisfied. 8. Dimensions
6.3 Screws having a nominal thread diameter-length com-
8.1 Unless otherwise specified, the dimensions shall con-
bi nation as specified in 6.2 and a breaking load exceeding 535
fonn to lhe req uirements of ANSIIASl4E-B.18.3..4M......OL..
kN' preferably shall be tested full size and shall meci The
full-size tensile properties in Table 3. When equipment of TABLE 4 Decarburlzation Limits for Threads A
sufficient capacity for such tests is not available. or if excessive
length of the screws makes full-size testing impractical, stan- Thread·Pitch.
Basic Thread
N - :r_I\. Root - 0.11\.
Height. h. _
P, mm min. mm mm
0.6135P mm
A
TABLE 2 Chemical Requirements 0.7 0.429 0.043
'.322

EJemenl
Compos~iOfl. % ,
0.8 0.491
0.613
'.368
0.460
0.049
0.061
1.25 0.767 0.575 0.077
Heal Analysis Product Analysis
L5 0.092
C"bon
Phosphorus, max
0.30 to 0.48
0.035
0.28 to 0.50
0.040 ,1.75 '''"
1.074
1.227
0.690
0806
0.920
0.107
0.123
SIiHur. max 0.040 0.045 '5 L53< 1.151 0.153

A See for alloy requirements. A See Fig. 1.

243
 ~ffi\l F 835M
DECARBURIZATION

.I h
•
FIG. 1 Oecarburization limits

81 8.3.5M as specified.
PERMISSIBLE \ ....'1"'" "f Rt,! ISSII ~E

""a!"" Iim"')
t W;,1wI
".1
lP<",rl«l " ...

9. Workmanship, Finish and Appearance

9.1 Sllrface Finish- The screws shall have a black (Ihennal
or chemical) oxide fini sh, unless otherwise specified.
9.2 Surface Discoll1;/wiries:
NOT PERMI SSIBLE N OT HR1,US$I'U
9.2.1 The surface discontinuities for these products shall (Con_'" IO<~" •• ~",._ __ \, Il'olonl .. I",I.,.eCU",
I~' t<lr< of ~ ..d) - d"<Oftl"'~'h")
conform IQ Specification F 788/F 788M and the additional
limitations specifi ed herein. PERMI SSIBL E \ \I,,,h,n

~
.".( Irood I.m",) PERMISS'8 L E 1 ...., I~ ·
9.2.2 Forging defects that connect the socket to the periph- J. '" lP<"r..d hm" ' 1

~
ery of the head are nOl permissible. Defects originating on the ,- r SEC"M' 9. 2 .2
periphery and with a traverse indicating a potential to intersect
arc not pennissible. Other forging defects are penni55ible
provided those located in the bearing area, fillet. and top
sunaces shall nOI have a depth exceeding 0.03 D or 0. 13 In , ~
~
PER MISSl8LE ,\I,th",
whichever is greater. For peripheral discontinuities. the maxi- ' p"e,ficdhm",)

mum depth may be 0.06 D not to exceed I mm (see Fig. 2).

9.2.3 Forging defects located in the socket wall within 0. 1 FIG. 2 Head Ofscontinuities
times the actual key engagement. T, from the bottom of the
socket are not permissible. Discontinuities located elsewhere in
the socket shall not have a length exceeding 0.25 T. or a 10. Number ofTesCs
max'imum depth of 0.03 D not to eltceed 0. 13 mm (see Fig. 3). 10.1 The requirements of this specification shall be..met in
9.2.4 Seams in the shank shall not exceed a depth of 0.03 0 continuous mass production for stock, and the manufacturer
or 0.2 mm, whichever is greater, shall make sample inspections to ensure that the product
9.2.5 No transverse discontinuities shall be permitted in the conforms to the speci fied requirements. Additional tests of
head-to-shank fi llet area. individual shipments of material are not ordinarily contem-
9.2.6 Threads shall have no laps at the root or on the flanks, plated. A record of individual heals of steel in each test lot shall
as shown in Fig. 4. Laps are pennitted at the crest (Fig. 4c) th'Lt be maintained. The container shall be coded to perniiridenti-
do not exceed 25 % of the basic thread depth, and on the fl anks fication of the lot.
outside the pitch cylinder. Longitudinal seams rolled beneath 10.2 When specified in the order. the manufacturer shall
the root of the thread and across the crests of cut threads are furni sh a test report certified to be the lasl complete set of
acceptable within the limits of 9.2.4. mechanical tests for each stock size in each shipment.
9.2.7 Quench cracks of any depth, any length, or in any 10.3 When additional tests are specified on the purchase
location are nOI permitted. order, a lot, for purposes of selecting test samples. shall c onsist
244
 ~t F 835M
0 .1OT (No ,·"ok. per·
m",.d," Oh" .... ) Thread Pitch , CMd
P. min.
~ NOT PEAMISSISlI Over 0.6 500~
~ ''', b>><of"",k., 0.6 200 gf
ot"""h,nO.IO T of
1>;0", "r ",ek.n Less than 0.6 Use optical evalL/ation
in 11.5.2.

11.5.3. 1 Take measurements at minor diameter (Reading

PEAM I$SI 8LE I ln 'he PERMISSIBU 1 No." ••
boltom of ",,,;k<l, n", '" «<d,.,O.lS T In knl'h Number I) on the thread crest bisector to determine base metal
,I>< "., of key <"P3t" ,nd not ,...th,n OJOr hardness. Take measurements (Reading Number 2) on the
.... "t) of b ... "f ",de, )
bisector 0.75 h fro m the minor measurement toward the crest.
FIG. 3 Socket Olscontlnultles
Also take measurements (Reading Number 3) on the thread
flank at the pitch line at a depth within 0.08 mm from the
surface. Reading Number 3 may be taken on the same or an
of all screws offered for inspection at onc time of onc diameter
adjacent thread.
and length. From each lot, the number of samples for each
11.5.4 Interpret microhardness readings as follows:
requirement shall be as follows:
11 .5.5 A decrease of more than 30 hardness points from
Number 01
Number of Pieces in Lot Samples
Reading Number I to Reading Number 2 shall be regarded as
decarburization and indicates the screw does not conform to
800 and less 1 specification requirements.
Over 800 10 8000, lnel
Over 6000 to 22 000, incl ,2
11.5.6 An increase of more than 30 hardness points from
Over 22 000 5 Reading Number I to Reading Number 3 shall be regarded as
carburization and indicates that the screw does not conform to
10.4 Should any sample fail to meet the requirements of a
specification requirements.
specified test, double the number of samples from the same lot
shall be rctested for the requirement(s) in which it failed . All of 12. Inspectio n
the additional samples shall conform to the specification or the
12.1 The inspector representing the purchaser, upon reason-
lot shall be rejected.
able notice, shall have free entry to all parts o f the manufac-
turer's works that concern the manufacture of the material
11. Test Methods
ordered. The manufacturer shall afford the inspector all rea-
11. 1 Chemical analysis shall be conducted in accordance sonable facilities to satisfy him that the material is being
with Test Methods A 751. furnished in accordance with this specificatio n. All tests and
11.2 Tensile properties shall be determined in accordance inspections required by the specification that are requested by
with Test Methods F 606M. the purchaser's representative shall be made before shipment,
11.3 Hardness shall be determined in accordance with Test and shall be so conducted as not to interfere unnecessarily with
Methods E 18. the operation of the works.
11.4 Embrittlement tests shall be conducted in accordance
with Test Methods F 606M. 13, Rejection a nd Rehearing
11.5 Decarburization and carburization tests shall be con- 13.1 Material that fails to confonn to the requirements of
ducted as follows: this specification may be rejected. Rejection should be reported
11.5. 1 Section the thread area of the bolt longitudinally to the producer or supplier promptly and in writing. In case o f
through the axis, mount, and polish it in accordance with dissatisfaction with the results of the test, the producer or
Methods E 3. Take measurements (I) at the minor diameter in supplier may make claim for a rehearing.
the center of the thread ridge and (2) 0.75 h toward the thread
crest on the perpendicular bisector of the thread ridge. Take a 14. Certification
measurement (3) on the thread flank approximately at the pitch 14.1 Upon request of the purchaser in the contract or order,
li ne at a depth of 0.08 mm. Use one of the two methods fo r a manufacturer's certification that the material was manufac-
carburizationldecarburization evaluation either optical or mi- tured and tested in accordance with this-specification, together
crohardness measurements. The microhardness measurement with a report of the latest mechanical tests of each stock size in
shall constitute a referee method in case of dispute. each shipment, shall be furnished at the time of shipment.
11.5.2 For optical measurement, etch the section in 2 - 4 %
nita!' Examine the surface of the etched samples under a 15. Responsibility
microscope at 100 X using a measuring eyepiece graduated in 15.1 The party responsible for the fastener shall be the
a.03-mm increments. The width of any light etching band organization that supplies the fastener to the purchaserarur
normally defines the decarburization depth. A dark etching certifies that the fastener was manufactured, sampled, tested
band indicates the possibility of carburization. and inspected in accordance with this specification and meets
11.5.3 Measure microhardness in accordance with Test all of its requirements.
Method E 384 on unetched specimens using a DPH 1360
indenter or a Knoop indenter using the follow ing load appli- 16. Packaging and Package Marking
cation: 16. 1 Paclw.ging:

245
 ~t F 835M
I.~AND
se AMS NOT
'E1ll1oII1SSIlI.E IoIIAJOIII DIAMETER

' ITC" Dl ...... ETER

1oII1NO R DIAIoIIET ER

'ERIoIIISSIIlI.E

~ "'".,-""
SUR FACE IoIIAJOR DI ...... ETER
IIIIREG ULARITlES

(b ) IoIIINORDIAIoIIETER

,E RIoII ISSIIlI.E

~
IoIIAJOR DI...... ETER
UU'I AHD SEAMS

, nc " DIAMETE R

(<) IoII INOR OIAM ETER

FIG. 4 Thread Discontinuttles

16. 1.1 Unless otherwise specified, packaging shall be in 16.2. 1.3 Name :md brand or trademark of the manufacturer,
accordance with Practice 0 395 1. 16.2.1 .4 Number of pieces,
16. 1.2 When special packaging requirements are required, 16.2. 1.5 Purchase order number, and
they shall be defi ned at the time of the inquiry and order.
16.2. 1.6 Country of origin.
16.2 Paclw.ge Marking:
16.2.1 Each shipping unit shall include or be plainly marked
17. Keywords
with the following info nnation:
16.2.1.1 ASTM designation. 17.1 cap screws; socket button head; socket fl at counter-
16.2. 1.2 Size, sunk head; alloy steel: steel

SUMMARY OF CHANGES

This section identifi es the location of selected changes to this specification that have been incorporated since
the -97 issue. For the convenience of the user, Committee F- 16 has highl ighted those changes that may impact
the use of this specification. This section may also include descriptions of the changes or reasons for the changes,
or both.

( I) In Table 4 Decarburization Li mits, deleted thread pi tch 0.5 . (3) Revised 11.5.3 to improve effectiveness of the microhard-
Microhardness tests diflicult to conduct because of thread size ness referee method.
restriction and indentation placcment. (4) In Figure I, deleted Reading 4 due to difficulty in thread
(2) In 11.5.1, deleted refere nce to Reading Number 4. size restriction and indentation placement.

The American Society for Testing and Materials tall.! no position respecting th(I validity of any palOOI rights asserted In 00IlII8Cfkln
with any item menlioMd in this standan:J. Users of Ihi$ standBrd lire expressly advis8d that delemlination t)/!he validity t)/ any such
pe/ellt rights. and /tie risk. t)/ i'J1mgemenr t)/$UdI rigIIls, are fHItire1y IhfIfr own rasporsibiIity.

This standard is sub;ec1 /0 reMs.ion at any Iima by /ha responsible tachnical ccmmittee IInd musI bet reviewed avery five restS 8fId
it nol revised, either reapproved or withdral'fll. Your comrn.tn/$ Ire invitoo either for revision of tfIis $/lIndard or for acJditional S18ndatds
and should bet IIddressed /0 A$TM Headquarters. Yoor comments will receive carelul CCfl$Idera/ion al a meeting t)/ the rrr.;pcxtSIbIa
I6dlnicat commlnee. Which you may a nend. If you feel that your commenls have not received I fSir hearing you should make your
views known 10 rhe AS TM Committee on Standan:Js. '00 Barr Harbor Drive, West ConshohocJ(en. PA 19428.

246