This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles
for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: A394 − 08 (Reapproved 2024)
Standard Specification for
Steel Transmission Tower Bolts, Zinc-Coated and Bare1
This standard is issued under the fixed designation A394; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope* ization established in the Decision on Principles for the
1.1 This specification covers the chemical and mechanical Development of International Standards, Guides and Recom-
requirements of hexagon and square-head zinc-coated steel mendations issued by the World Trade Organization Technical
bolts and atmospheric corrosion-resistant bolts, in nominal Barriers to Trade (TBT) Committee.
thread diameters of 1⁄2, 5⁄8, 3⁄4 , 7⁄8 and 1 in. for use in the
2. Referenced Documents
construction of transmission towers, substations, and similar
steel structures. The various types of bolts covered in this 2.1 ASTM Standards:2
specification are: A563 Specification for Carbon and Alloy Steel Nuts (Metric)
1.1.1 Type 0—Hot-dip zinc-coated bolts made of low or A0563_A0563M
medium carbon steel. D3951 Practice for Commercial Packaging
1.1.2 Type 1—Hot-dip zinc-coated bolts made of medium F436 Specification for Hardened Steel Washers (Metric)
carbon steel, quenched and tempered. F0436_F0436M
1.1.3 Type 2—Withdrawn in 2005.
iTeh Standards
1.1.4 Type 3—Bare (uncoated), quenched and tempered
F606/F606M Test Methods for Determining the Mechanical
Properties of Externally and Internally Threaded
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bolts made of weathering steel. Fasteners, Washers, Direct Tension Indicators, and Rivets
F788/F788M Specification for Surface Discontinuities of
1.2 Annex A1 of this specification covers hot-dip zinc-
Bolts, Screws, Studs, and Rivets, Inch and Metric Series
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coated steel ladder bolts, step bolts, and support-equipment
F1470 Practice for Fastener Sampling for Specified Me-
bolts.
chanical Properties and Performance Inspection
1.3 Nuts and washers that are supplied under this specifica- F1789 Terminology for F16 Mechanical Fasteners
tion that are hot-dip zinc coated shall be in accordance with F2329 Specification for Zinc Coating, Hot-Dip, Require-
4.4. ASTM A394-08(2024)
ments for Application to Carbon and Alloy Steel Bolts,
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1.4 Terms used in this specification are defined in Termi- Screws, Washers, Nuts, and Special Threaded Fasteners
nology F1789. G101 Guide for Estimating the Atmospheric Corrosion Re-
sistance of Low-Alloy Steels
1.5 The values stated in inch-pound units are to be regarded
as standard. No other units of measurement are included in this 2.2 ASME Standards:3
standard. B1.1 Unified Screw Threads
B18.2.1 Square and Hex Bolts and Screws
1.6 The following safety hazards caveat pertains only to the B18.24 Part Identifying Number (PIN) Code System Stan-
test methods portion, Section 11, of this specification. This dard for B18 Fastener Products
standard does not purport to address all of the safety concerns,
if any, associated with its use. It is the responsibility of the user 3. Ordering Information
of this standard to establish appropriate safety, health, and
3.1 Orders for products under this specification shall include
environmental practices and determine the applicability of
the following:
regulatory limitations prior to use.
3.1.1 Quantity (number of bolts and accessories).
1.7 This international standard was developed in accor-
dance with internationally recognized principles on standard-
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
1
This specification is under the jurisdiction of ASTM Committee F16 on contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Fasteners and is the direct responsibility of Subcommittee F16.02 on Steel Bolts, Standards volume information, refer to the standard’s Document Summary page on
Studs and Nuts. the ASTM website.
3
Current edition approved Jan. 1, 2024. Published January 2024. Originally Available from American Society of Mechanical Engineers (ASME), ASME
approved in 1955. Last previous edition approved in 2015 as A394 – 08 (2015). International Headquarters, Two Park Ave., New York, NY 10016-5990, http://
DOI: 10.1520/A0394-08R24. www.asme.org.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
A394 − 08 (2024)
3.1.2 Name of products, including accessories such as A563 intentionally added shall be quenched only in oil from above
nuts and F436 washers when desired. the austenitizing temperature.
3.1.3 Dimensions, including nominal bolt diameter and 4.2.2 Type 3 bolts shall be quenched only in oil from above
length. For bolts other than transmission-tower bolts, complete the austenitizing temperature.
dimensions are required (see Annex A1). 4.2.3 Type 1 bolts, regardless of the steel used, and Type 3
3.1.4 Type of bolt (for example, Type 0, 1, or 3). bolts shall be tempered by reheating to not less than 800 °F.
3.1.4.1 When non-zinc-coated atmospheric corrosion- 4.2.4 Cold-headed Type 0 bolts shall be stress relief an-
resistant steel is required, Type 3 bolts shall be specified by the nealed before zinc coating to remove cold work effects such
purchaser. that the hardness measured anywhere on the surface or through
3.1.5 ASTM designation and year of issue. When year of the cross-section shall meet the requirements in 6.1.
issue is not specified, bolts shall be furnished to the latest issue.
3.1.6 Additional requirements, if any, are to be specified on 4.3 Threads may be rolled or cut.
the purchase order: 4.4 Zinc Coatings, Hot Dip:
3.1.6.1 Shear-strength testing (see 6.2.1 and 6.2.2). Include 4.4.1 Type 0 and Type 1 bolts shall be hot-dip zinc-coated
type of test required. accordance with the requirements of Specification F2329,
3.1.6.2 Additional tests. except that the minimum average weight (thickness) of zinc
3.1.6.3 Inspection (see 12.1 and 12.2). coating shall be 1.65 oz/ft2 (0.0028 in.) and the minimum
3.1.6.4 Certification (see 14.1). weight of zinc coating on any one item shall be 1.50 oz/ft 2
3.1.6.5 Test reports (see 14.1). (0.0025 in.).
3.1.6.6 Other finishes, specify other protective finish, if 4.4.2 Bolt threads shall not be cut, rolled, or otherwise
required. finished after zinc coating.
NOTE 1—Examples of ordering description: 4.4.3 Hot-dip zinc-coated nuts furnished under Specifica-
(1) 1000 square-head transmission-tower bolts, 1⁄2 by 2 in. Type 1, hot-dip tion A563 shall be tapped after zinc coating.
zinc coated, shear testing required, ASTM A394 – XX, with hot-dip 4.4.4 Hot-dip zinc-coated nuts and washers supplied for use
zinc-coated hex nuts, Grade DH, ASTM A563 – XX,
iTeh Standards
(2) 1000 transmission tower bolts, 1⁄2 by 2 in. Type 0, hot-dip zinc coated, with bolts under this specification shall be zinc-coated in
ASTM A394 – XX, with hot-dip zinc-coated hex nuts, Grade A, ASTM accordance with 4.4.1.
A563 – XX.
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4.5 Protection of Uncoated Surfaces—When hot-dip zinc-
(3) 1000 transmission tower bolts, 1⁄2 by 2 in. Type 3, ASTM A394 – XX,
coated nuts are ordered, the cutting oil or some other suitable
with hex nuts, Grade DH3 weathering steel, ASTM A563 – XX and with
2 circular washers, Type 3, ASTM F436 – XX. substance shall be left on the uncoated surface to inhibit rusting
3.1.7 For establishment of a partDocument
identifying system, see Preview
during shipment and storage. It is recommended that the
ASME B18.24. additional lubricant be clean and dry to the touch.
3.2 Recommended Nuts: 4.6 Secondary Processing:
ASTM A394-08(2024)
3.2.1 Unless otherwise specified, all nuts on these bolts shall 4.6.1 If any processing which can affect the mechanical
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be hex style and conform to the requirements of Specification properties or performance of the bolts is performed after the
A563 as follows. initial testing, the bolts shall be retested for all specified
Bolt Type Nut Grade Finish mechanical properties and performance requirements affected
0 A hot-dip zinc-coated by the reprocessing.
1 DH hot-dip zinc-coated
4.6.2 When the secondary processing is heat treatment, the
3 DH3 plain
bolts shall be tested for all specified mechanical properties.
3.3 Recommended Washers: Hot-dip zinc-coated bolts shall be tested for all specified
3.3.1 Suitable washers for use with Type 0 are hot-dip mechanical properties.
zinc-coated carbon-steel washers with dimensions that are in
accordance with Specification F436. Suitable washers for use 5. Chemical Composition
with Type 1 bolts are hot-dip zinc-coated Type 1 hardened-steel
washers that are in accordance with Specification F436. Suit- 5.1 Type 0 and Type 1 bolts shall conform to the chemical
able washers for use with Type 3 bolts are Type 3 hardened- composition requirements specified in Table 1.
steel washers that are in accordance with Specification F436. 5.2 Type 3 bolts shall conform to one of the chemical
compositions specified in Table 2. The selection of the chemi-
4. Materials and Manufacture cal composition A, B, C, D, E, or F shall be at the option of the
4.1 Steel for the manufacture of bolts shall be made by any bolt manufacturer. See Guide G101 for methods of estimating
of the following processes: open-hearth, electric-furnace, or the atmospheric corrosion resistance of low alloy steels.
basic-oxygen.
4.2 Heat Treatment: 6. Mechanical Properties
4.2.1 Type 1 bolts produced from medium carbon steel shall 6.1 Tension Test—Types 0, 1, and 3 bolts having a length
be quenched in a liquid medium from above the austenizing equal to or more than 3 diameters shall be wedge tension tested
temperature. Type 1 bolts produced from medium carbon steel as specified in 11.1 and shall conform to the tensile strength
to which chromium, nickel, molybdenum, or boron were requirements in Table 3. Zinc-coated bolts shall be tested after
2
A394 − 08 (2024)
TABLE 1 Chemical Requirements and Head Markings
Element, %
Head Marking Bolt Type
Carbon Manganese Phosphorus Sulfur Boron
0 0.55 max ... 0.048 max 0.058 max ...
1 0.28/0.55 0.60 min 0.048 max 0.058 max ...
3 ... ... ... See Table 2 ...
TABLE 2 Chemical Requirements for Type 3 Heavy Hex Structural BoltsA
Composition, %
Element Type 3 BoltsA
A B C D E F
Carbon:
Heat Analysis 0.33–0.40 0.38–0.48 0.15–0.25 0.15–0.25 0.20–0.25 0.20–0.25
Product Analysis 0.31–0.42 0.36–0.50 0.14–0.26 0.14–0.26 0.18–0.27 0.19–0.26
Manganese:
Heat Analysis 0.90–1.20 0.70–0.90 0.80–1.35 0.40–1.20 0.60–1.00 0.90–1.20
Product Analysis 0.86–1.24 0.67–0.93 0.76–1.39 0.36–1.24 0.56–1.04 0.86–1.24
Phosphorus:
Heat Analysis 0.035 max 0.06–0.125 0.035 max 0.035 max 0.035 max 0.035 max
Product Analysis 0.040 max 0.06–1.25 0.040 max 0.040 max 0.040 max 0.040 max
Sulfur:
Heat Analysis 0.040 max 0.040 max 0.040 max 0.040 max 0.040 max 0.040 max
iTeh Standards
Product Analysis 0.045 max 0.045 max 0.045 max 0.045 max 0.045 max 0.045 max
Silicon:
Heat Analysis 0.15–0.35 0.30–0.50 0.15–0.35 0.25–0.50 0.15–0.35 0.15–0.35
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Product Analysis 0.13–0.37 0.25–0.55 0.13–0.37 0.20–0.55 0.13–0.37 0.13–0.37
Copper:
Heat Analysis 0.25–0.45 0.20–0.40 0.20–0.50 0.30–0.50 0.30–0.60 0.20–0.40
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Product Analysis 0.22–0.48 0.17–0.43 0.17–0.53 0.27–0.53 0.27–0.63 0.17–0.43
Nickel:
Heat Analysis 0.25–0.45 0.50–0.80 0.25–0.50 0.50–0.80 0.30–0.60 0.20–0.40
Product Analysis 0.22–0.48 0.47–0.83 0.22–0.53 0.47–0.83 0.27–0.63 0.17–0.43
Chromium:
Heat Analysis 0.45–0.65 0.50–0.75 0.30–0.50 0.50–1.00 0.60–0.90 0.45–0.65
Product Analysis ASTM A394-08(2024)
0.42–0.68 0.47–0.83
0.27–0.53 0.45–1.05 0.55–0.95 0.42–0.68
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Vanadium:
Heat Analysis B
0.020 min B B B B
B B B B B
Product Analysis 0.010 min
Molybdenum:
B B B B
Heat Analysis 0.06 max 0.10 max
B B B B
Product Analysis 0.07 max 0.11 max
Titanium: ... ... ... ... ... ...
B B B B B
Heat Analysis 0.05 max
B B B B B
Product Analysis 0.06 max
A
A, B, C, D, E, and F are classes of material used for Type 3 bolts. Selection of a class shall be at the option of the bolt manufacturer.
B
These elements are not specified or required.
TABLE 3 Tensile StrengthA
coating. Bolts too short for full size testing or for other reasons
Nominal Minimum Tensile Load, lbf
not subject to tension tests, shall meet the following hardness Size, Type 0B Types 1 and 3C
requirements: in.
Min Max ⁄
12 10 500 17 050
⁄
58 16 700 27 100
3⁄4 24 700 40 100
Type 0—Rockwell B 80 100
7⁄8 34 200 55 450
Types 1 and 3—Rockwell C 25 34
1 44 850 72 700
6.2 Shear Strength: A
Tensile strength based on the thread stress area, As, is calculated as follows:
6.2.1 When specified in the original inquiry and order, bolts, As = 0.7854 [ D − (0.9743/N)] 2
except as excluded in 6.2.2, shall be shear strength tested in where:
accordance with 11.2 and shall meet the requirements given in D = nominal diameter, and
N = threads per inch.
Table 4. B
Based on 74 000 psi unit tensile strength.
6.2.2 Bolts with unthreaded body lengths shorter than two C
Based on 120 000 psi unit tensile strength.
times the nominal bolt diameter, are subject to shear strength
