Download - ASTM BOLT & NUTS
ASTM Bolt Specifications
The American Society for Testing and Materials, is an international standards organization that develops and publishes
voluntary consensus technical standards for a wide range of materials, products, systems, and services.
A153 - Hot dip galvanizing specification.
A193 - Alloy steel and stainless steel bolting materials for high temperature service.
A194 - Carbon and alloy nuts for bolts for high pressure and high temperature service.
A307 - Carbon steel bolts and studs ranging from 1/4" through 4" diameter.
A320 - Alloy steel and stainless steel bolting materials for low temperature service.
A325 - Structural bolts, steel, heat treated, 120/105 ksi minimum tensile strength.
A354 - Quenched and tempered alloy bolts, studs, and other externally threaded fasteners.
A449 - Quenched and tempered steel bolts and studs.
A490 - Structural bolts, alloy steel, heat treated, 150 ksi tensile strength.
A563 - Standard specification for carbon and alloy steel nuts.
F1554 - Anchor bolts designed to anchor structural supports to concrete foundations.
F2329 - New specification covering hot dip galvanizing.
ASTM A153
Quick Links
Galvanizing
FAQ: Galvanizing High Strength Bolts
FAQ: Galvanized Nuts Tapped Oversize
Scope
The ASTM A153 specification covers zinc coating (hot-dip) on iron and steel hardware. A newer and more appropriate
specification developed in 2005 covering the requirement for hot-dip galvanizing of bolts, screws, nuts, washers and other
threaded fasteners is ASTM F2329. It is not yet widely used since many of the ASTM specifications covering bolts, nuts and
washers do not reference it. As soon as revisions referencing F2329 are made to these fastener specifications, F2329 will
become more common. ASTM A123 is a related hot-dip galvanizing specification covering iron and steel products made
from rolled pressed and forged shapes, castings, plates, bars, and strips. The equivalent AASHTO specification to ASTM
A153 is AASHTO M232.
ASTM A193
Quick Links
Hex Bolts
A193 All Thread Rod
ASTM A194
Thread Pitch Chart
Scope
Originally approved in 1936, this specification is heavily utilized in petroleum and chemical construction applications. The
ASTM standard covers alloy steel and stainless steel bolting materials for high temperature or high pressure service. This
specification includes fasteners intended for use in pressure vessels, valves, flanges, and fittings. Although, this material is
often available in national coarse (UNC) thread pitches, if being used in traditional applications, threads are specified 8
threads per inch (tpi) for diameters above one inch.
Below is a basic summary of a few of the common grades. ASTM A193 covers a number of other standard specifications not
covered in this description including B5, B6, and B16.
Grades
B7 Alloy steel, AISI 4140/4142 quenched and tempered
B8 Class 1 Stainless steel, AISI 304, carbide solution treated.
B8M Class 1 Stainless steel, AISI 316, carbide solution treated.
B8 Class 2 Stainless steel, AISI 304, carbide solution treated, strain hardened
B8M Class 2 Stainless steel, AISI 316, carbide solution treated, strain hardened
Mechanical Properties
Grade Size Tensile ksi, min Yield, ksi, min Elong, %, min RA % min
B7
Up to 2-1/2 125 105 16 50
2-5/8 - 4 115 95 16 50
4-1/8 - 7 100 75 18 50
B8 Class 1 All 75 30 30 50
B8M Class 1 All 75 30 30 50
B8 Class 2
Up to 3/4 125 100 12 35
7/8 - 1 115 80 15 35
1-1/8 - 1-1/4 105 65 20 35
1-3/8 - 1-1/2 100 50 28 45
Grade Size Tensile ksi, min Yield, ksi, min Elong, %, min RA % min
B8M Class 2
Up to 3/4 110 95 15 45
7/8 - 1 100 80 20 45
1-1/8 - 1-1/4 95 65 25 45
1-3/8 - 1-1/2 90 50 30 45
Recommended Nuts and Washers
Bolt Grade Nuts Washers
B7 A194 Grade 2H F436
B8 Class 1 A194 Grade 8 SS304
B8M Class 1 A194 Grade 8M SS316
B8 Class 2 A194 Grade 8 SS304
B8M Class 2 A194 Grade 8M SS316
Strain hardened nuts available as a supplementary requirement
ASTM A194
Quick Links
Heavy Hex Bolts
ASTM A193
Nut Weight Chart
Scope
The ASTM A194 specification covers carbon, alloy and stainless steel nuts intended for use in high-pressure and/or high-
temperature service. Unless otherwise specified, the American National Standard Heavy Hex Series (ANSI B 18.2.2) shall
be used. Nuts up to and including 1 inch nominal size shall be UNC Series Class 2B fit. Nuts over 1 inch nominal size shall
be either UNC Series Class 2B fit or 8 UN Series Class 2B fit. High strength ASTM A194 grade 2H nuts are common in the
marketplace and are often substituted for ASTM A563 grade DH nuts due to the limited availability of DH nuts in certain
diameters and finishes.
Grades
2 Carbon steel heavy hex nuts
2H Quenched & tempered carbon steel heavy hex nuts
2HM Quenched & tempered carbon steel heavy hex nuts
4 Quenched & tempered carbon-molybdenum heavy hex nuts
7 Quenched & tempered alloy steel heavy hex nuts
7M Quenched & tempered alloy steel heavy hex nuts
8 Stainless AISI 304 heavy hex nuts
8M Stainless AISI 316 heavy hex nuts
Mechanical Properties Grade Identification Markings
Grade
Identification
Marking5
Specification Material Nominal
Size, In.
Tempering
Temp. °F
Proof
Load
Stress,
ksi
Hardness
Rockwell See
Note Min Max
ASTM A194
Grade 2
Medium
Carbon
Steel
1/4 - 4 1000 150 159 352 1,2,3
ASTM A194
Grade 2H
Medium
Carbon
Steel,
Quenched
and
Tempered
1/4 - 4 1000 175 C24 C38 1,2
ASTM A194
Grade 2HM
Medium
Carbon
Steel,
Quenched
and
1/4 - 4 1000 150 159 237 1,2,3
Tempered
ASTM A194
Grade 4
Medium
Carbon
Alloy
Steel,
Quenched
and
Tempered
1/4 - 4 1100 175 C24 C38 1,2
ASTM A194
Grade 7
Medium
Carbon
Alloy
Steel,
Quenched
and
Tempered
1/4 - 4 1100 175 C24 C38 1,2
ASTM A194
Grade 7M
Medium
Carbon
Alloy
Steel,
Quenched
and
Tempered
1/4 - 4 1100 150 159 237 1,2,3
ASTM A194
Grade 8
Stainless
AISI 304 1/4 - 4 - 80 126 300 4
ASTM A194
Grade 8M
Stainless
AISI 316 1/4 - 4 - 80 126 300 4
NOTES:
1. The markings shown for all grades of A194 nuts are for cold formed and hot forged nuts. When nuts are machined from bar stock, the nut must additionally be marked with the
letter 'B'. The letters H and M indicate heat treated nuts. 2. Properties shown are those of coarse and 8-pitch thread heavy hex nuts. 3. Hardness numbers are Brinell Hardness. 4. Nuts that are carbide-solution treated require additional letter A - 8A or 8MA. 5. All nuts shall bear the manufacturer’s identification mark. Nuts shall be legibly marked on
one face to indicate the grade and process of the manufacturer. Marking of wrench flats or bearing surfaces is not permitted unless agreed upon between manufacturer and purchaser. Nuts coated with zinc have an asterisk (*) marked after the grade symbol. Nuts coated with cadmium shall have a plus sign (+) marked after the grade symbol.
6. Other less common grades exist, but are not listed here.
Inch Fastener Standards. 7th ed. Cleveland: Industrial Fasteners Institute, 2003. N-80 - N-81.
ASTM A307
Quick Links
Hex Bolts
Bent Anchor Bolts
A307 All Thread Rod
ASTM A563 Hex Nuts
Scope
The ASTM A307 specification covers carbon steel bolts and studs ranging from 1/4” through 4” diameter. This is your
everyday, run of the mill bolt specification often manufactured using A36 round bar. There are three grades A, B, and C*
which denote tensile strength, configuration, and application. Refer to the Mechanical Properties Chart for the subtle
strength differences within each grade.
Grades
A Headed bolts, threaded rods and bent bolts intended for general applications.
B Heavy hex bolts and studs intended for flanged joints in piping systems with cast iron flanges.
C* Nonheaded anchor bolts, either bent or straight, intended for structural anchorage purposes. The
end of a grade C anchor bolt intended to project from the concrete will be painted green for
identification purposes. Permanent marking is a supplemental requirement. *As of August 2007,
grade C has been replaced by specification F1554 grade 36. We will continue to supply grade C, if
required by the project.
Mechanical Properties
Grade Tensile, ksi Yield, min, ksi Elong %, min
A 60 min -- 18
B 60 - 100 -- 18
C* 58 - 80 36 23
Recommended Nuts and Washers
Nuts
Washers A307 Grades A & C* A307 Grade B
1/4 - 1-1/2 1-5/8 - 4 1/4 - 4
A563A Hex A563A Heavy Hex A563A Heavy Hex F844
ASTM A320
Quick Links
Heavy Hex Bolts
ASTM A193
Strength by Grade
Scope
Originally approved in 1948, the ASTM A320 specification covers alloy steel and stainless steel bolting materials for low
temperature service. This standard covers rolled, forged, or strain hardened bars, bolts, screws, studs, and stud bolts used
for pressure vessels, valves, flanges, and fittings. Like the ASTM A193 specification, unless otherwise specified, the 8UN
thread series is specified on fastener larger than 1” in diameter.
Below is a basic summary of a few of the common grades within the ASTM A320 specification. A number of other less
common grades of ASTM A320 exist, but not covered in the description below.
Grades
L7 Alloy steel AISI 4140/4142 Quenched and tempered
L43 Alloy steel AISI 4340 Quenched and tempered
B8 Class 1 Stainless steel AISI 304, carbide solution treated
B8M Class 1 Stainless steel AISI 316, carbide solution treated
B8 Class 2 Stainless steel AISI 304, carbide solution treated, strain hardened
B8M Class 2 Stainless steel AISI 316, carbide solution treated, strain hardened
Mechanical Properties
Grade Size Tensile,
ksi, min
Yield,
ksi, min
Charpy Impact
20-ft-lbf
@ temp
Elong,
%, min RA, %, min
L7 Up to 21/2 125 105 -150° F 16 50
L43 Up to 4 125 105 -150° F 16 50
B8
Class 1 All 75 30 N/A 30 50
B8M
Class 1 All 75 30 N/A 30 50
B8
Class 2
Up to 3/4 125 100 N/A 12 35
7/8 - 1 115 80 N/A 15 35
11/8 - 11/4 105 65 N/A 20 35
13/8 - 11/2 100 50 N/A 28 45
B8M
Class 2
Up to 3/4 110 95 N/A 15 45
7/8 - 1 100 80 N/A 20 45
11/8 - 11/4 95 65 N/A 25 45
13/8 - 11/2 90 50 N/A 30 45
Recommended Nuts and Washers
Grade Nuts Washers
L7 A194 Grade 4 or 7 F436
L43 A194 Grade 4 or 7 F436
B8 Class 1 A194 Grade 8 SS304
B8M Class 1 A194 Grade 8M SS316
B8 Class 2 A194 Grade 8, strain hardened SS304
B8M Class 2 A194 Grade 8M, strain hardened SS316
ASTM A325
Quick Links
DTI Washer
Large Diameter A325
Rotational Capacity
Bolt Torque Chart
Scope
The ASTM A325 specification covers high strength heavy hex structural bolts from ½” diameter through 1-1/2” diameter.
These bolts are intended for use in structural connections and therefore have shorter thread lengths than standard hex bolts.
Refer to the Structural Bolts page of our site for thread lengths and other related dimensions.
This specification is applicable to heavy hex structural bolts only. For bolts of other configurations and thread lengths with
similar mechanical properties, see Specification A 449.
Bolts for general applications, including anchor bolts, are covered by Specification A 449. Also refer to Specification A 449
for quenched and tempered steel bolts and studs with diameters greater than 1-1/2" but with similar mechanical properties.
Types
TYPE 1 Medium carbon, carbon boron, or medium carbon alloy steel.
TYPE 2 Withdrawn November 1991.
TYPE 3 Weathering steel.
T Fully threaded A325. (Restricted to 4 times the diameter in length)
M Metric A325.
Connection Types
SC Slip critical connection.
N Bearing type connection with threads included in the shear plane.
X Bearing-type connection with threads excluded from the shear plane.
Mechanical Properties
Size Tensile, ksi Yield, ksi Elong. %, min RA %, min
1/2 - 1 120 min 92 min 14 35
1-1/8 - 1-1/2 105 min 81 min 14 35
Recommended Nuts and Washers
Nuts Washers
Type 1 Type 3 Type 1 Type 3
Plain Galvanized Plain
A563C, C3, D, DH, DH3 A563DH A563C3, DH3 F436-1 F436-3
Note: Nuts conforming to A194 Grade 2H are a suitable substitute for use with A325 heavy hex
structural bolts. The ASTM A563 Nut Compatibility Chart has a complete list of specifications.
ASTM A354
Quick Links
Hex Bolts
Anchor Rods
Strength by Grade
Scope
The ASTM A354 specification covers the chemical and mechanical requirements of quenched and tempered alloy steel
bolts, studs, and other externally threaded fasteners 4" and under in diameter.
Two strength levels, grade BC and grade BD, are summarized in the chart below. This specification is unrestricted in its
configuration and can be a headed bolt, bent bolt, or threaded rod.
Grades
A354
BD
A354 grade BD bolts are higher in strength than A354 grade BC and equal in strength to
ASTM A490 bolts. Unlike ASTM A490 however, the A354 BD specification is
unrestricted in its configuration. Since A490 bolts are heavy hex structural bolts and do
not exceed 1-1/2" diameter, specification A354 BD should be considered for anchor bolts,
threaded rods, other styles of headed bolts, and bolts larger than 1-1/2" diameter where
similar mechanical properties are desired. A354 grade BD does not require a magnetic
particle test as is required by the A490 specification.
Research conducted on bolts of similar material and manufacture indicates that hydrogen-
stress cracking or stress cracking corrosion may occur on hot-dip galvanized Grade BD
bolts. For more information about this subject, please see our FAQ that
addresses galvanizing of high strength bolts.
A354
BC
Lower in strength than grade BD.
Mechanical Properties
Grade Size Tensile, ksi, min Yield, ksi, min Elong %, min RA %, min
BC 1/4 - 2-1/2 125 109 16 50
2-5/8 - 4 115 99 16 45
BD 1/4 - 2-1/2 150 130 14 40
2-5/8 - 4 140 115 14 40
Recommended Nuts and Washers
Nuts
Washers Grade BC Grade BD
Plain Galvanized Plain
A563C Heavy Hex A563DH Heavy Hex A563DH Heavy Hex F436
* Nuts of other grades load stresses greater than the specified grade are suitable. Follow the link for
an ASTM A563 Nut Compatibility Chart.
ASTM A449
Quick Links
Thread Pitch Chart
Ask the Expert
Bolt Torque Chart
Scope
ASTM A449 covers headed bolts, rods, and anchor bolts in diameters ranging from 1/4" through
3" inclusive. It is a medium strength bolt manufactured from a medium carbon or alloy steel that
develops its mechanical values through a heat treating process. It is intended for general
engineering applications.
ASTM A449 is virtually identical in chemistry and strength to ASTM A325 and SAE J429 grade
5. However, A449 is more flexible in the sense that it covers a larger diameter range and is not
restricted by a specific configuration.
TYPES
TYPE 1 Plain carbon steel, carbon boron steel, alloy steel, or alloy boron steel.
TYPE 2 Withdrawn 2003
TYPE 3 Weathering steel.
MECHANICAL PROPERTIES
Size Tensile, ksi Yield, ksi Elong. %, min RA %, min
1/4 - 1 120 min 92 min 14 35
1-1/8 - 1-1/2 105 min 81 min 14 35
1-5/8 - 3 90 min 58 min 14 35
RECOMMENDED NUTS and WASHERS
Nuts
Washers Plain Galvanized
1/4 - 1-1/2 1-5/8 - 3 1/4 - 3
A563B Hex A563A Heavy Hex A563DH Heavy Hex F436
Note: Nuts of other grades having proof load stresses greater than the specified grade are suitable.
The ASTM A563 Nut Compatibility Chart has a complete list of specifications.
ASTM A490
Quick Links
DTI Washer
Bolt Glossary
Bolt Torque Chart
Scope
The ASTM A490 specification covers quenched and tempered, alloy steel, heavy hex structural bolts from ½” diameter
through 1½” diameter with a minimum 150 ksi tensile. These bolts are intended for use in structural connections and
therefore have shorter thread lengths than standard hex bolts. Refer to the Structural Bolts page of our site for thread
lengths and other related dimensions. A490 bolts are similar in application and dimensions to A325 heavy hex structural
bolts but are made from an alloy steel rather than a medium carbon steel, resulting in a higher strength fastener.
The A490 specification is applicable to heavy hex structural bolts only. For bolts with different thread lengths than specified
for structural bolts but with similar mechanical properties, see Specification A354 grade BD.
ASTM A490 bolts shall not be coated by hot-dip galvanizing, mechanical deposition, or electroplating with zinc or other
metallic coatings due to the potential risk of hydrogen embrittlement.
Additional testing in the form of Magnetic Particle Inspection for Longitudinal Discontinuities and Transverse Cracks is a
requirement of the A490 specification.
Types
TYPE 1 Medium carbon and alloy steel.
TYPE 2 Withdrawn in 2002.
TYPE 3 Weathering steel.
M Metric A490.
Connection Types
SC Slip critical connection.
N Bearing type connection with threads included in the shear plane.
X Bearing type connection with threads excluded from the shear plane.
Mechanical Properties
Size Tensile, ksi Yield, ksi Elong. %, min RA %, min
1/2 - 1-1/2 150-173 130 14 40
Recommended Nuts and Washers
Nuts Washers
Type 1 Type 3 Type 1 Type 3
A563DH A563DH3 F436-1 F436-3
Note: Nuts conforming to A194 Grade 2H are a suitable substitute for use with A490 heavy hex structural bolts. Follow the
link for anASTM A563 Nut Compatibility Chart.
Notes
1. The bolts shall not be coated by hot-dip zinc coating, mechanical deposition, or electroplating with zinc or other
metallic coatings due to the potential for hydrogen embrittlement. Read more about issues with galvanizing ASTM
A490.
2. Each sample representative of the lot shall be magnetic particle inspected for longitudinal discontinuities and
transverse cracks.
ASTM A563
Quick Links
Thread Pitch Chart
Ask the Expert
Bolt Torque Chart
The ASTM A563 specification covers the chemical and mechanical requirements for carbon and alloy steel nuts used on
bolts, studs, and externally threaded fasteners. The charts below address over tapping allowances for hot-dip galvanized
nuts, grade marking requirements, and mechanical requirements. For information on suitable nuts for various grades of
bolts, visit theNut Compatibility Chart.
According the A563 specification, "The requirements for any grade of nut may, at the supplier's option, and with notice to the
purchaser, be fulfilled by furnishing nuts of one of the stronger grades specified herein unless such a substitution is barred in
the inquiry and purchase order". This is important because some nut grades are not readily available in certain sizes and
finishes. Additionally, the specification allows for the substitution of ASTM A194 grade 2H nuts in lieu of A563 grade DH nuts
due to the lack of availability of grade DH nuts in nominal sizes ¾" and larger.
Hot-dip galvanized nuts must be tapped oversize to allow for the added thickness of the zinc on the threads of the externally
threaded fastener. These allowances are addressed in the chart below and a more detailed explanation of this issue can be
found in theFrequently Asked Questions section of this site.
Various nut styles exist and to some degree are determined by their grade. These styles include hex, heavy
hex, square, jam, coupling, and sleeve.
Scope
Standard specification for carbon and alloy steel nuts.
Grades A Low carbon steel, hex or heavy hex
B Low carbon steel, hex or heavy hex
C Carbon steel, quenched and tempered, heavy hex
D Carbon steel, quenched and tempered, heavy hex
DH Carbon steel, quenched and tempered, heavy hex
C3 Weathering steel, quenched and tempered, heavy hex
DH3 Weathering steel, quenched and tempered, heavy hex
Mechanical Properties
Grade Style Size, in.
Proof Load, ksi
Hardness, HBN
Black Galvanized
A
Hex 1/4 - 1-1/2 90 68 116 - 302
Heavy Hex 1/4 - 4 100 75 116 - 302
B
Heavy Hex 1/4 - 1 133 100 121 - 302
Heavy Hex 1-1/8 - 1-1/2 116 87 121 - 302
C / C3 Heavy Hex 1/4 - 4 144 144 143 - 352
D Heavy Hex 1/4 - 4 150 150 248 - 352
DH / DH3 Heavy Hex 1/4 - 4 175 150 248 - 352
For UNC, 8UN, 6UN, and Coarse Pitch Threads
Grade Identification Markings
Grade Identification
Marking Specification Material
Nominal
Size, In.
Proof Load
Stress, ksi
Hardness
Rockwell See
Note
Min Max
No Mark
ASTM A563
Grade O Carbon Steel 1/4 - 1-1/2 69 B55 C32 2,3
ASTM A563
Grade A Carbon Steel 1/4 - 1-1/2 90 B68 C32 2,3
ASTM A563
Grade B Carbon Steel
1/4 - 1 120
B69 C32 2,3
>1 - 1-1/2 105
ASTM A563
Grade C
Carbon Steel, may be
Quenched and Tempered 1/4 - 4 144 B78 C38 4
ASTM A563
Grade C3
Atmospheric Corrosion
Resistant Steel, may be
Quenched and Tempered
1/4 - 4 144 B78 38 4,6
ASTM A563
Grade D
Carbon Steel, may be
Quenched and Tempered 1/4 - 4 150 B84 C38 5
ASTM A563
Grade DH
Carbon Steel, Quenched and
Tempered 1/4 - 4 175 C24 C38 5
ASTM A563
Grade DH3
Atmospheric Corrosion
Resistant Steel, Quenched
and Tempered
1/4 - 4 175 C24 C38 4,6
NOTES:
1. In addition to the indicated grade marking, all grades, except A563 grades O, A, and B, must be marked for
manufacturer identification.
2. Nuts are not required to be marked unless specified by the purchaser. When marked, the identification marking
shall be the grade letter O, A, or B.
3. Properties shown are those of nonplated or noncoated coarse thread nuts.
4. Properties shown are those of coarse thread heavy hex nuts.
5. Properties shown are those of coarse thread heavy hex nuts. Other nuts styles and fine threads may apply.
6. The nut manufacturer, at his option, may add other markings to indicate the use of atmospheric corrosion
resistant steel.
Inch Fastener Standards. 7th ed. Cleveland: Industrial Fasteners Institute, 2003. n-80-n-81.
Thread Dimensions and Oversizing Allowances
for Nuts: Hot Dipped Galvanized per Specification A153, C1.C
Nominal Nut Size, in. and Pitch Diametral Allowance, in.
Pitch Diameter
Min Max
0.250 - 20 0.016 0.2335 0.2384
0.312 - 18 0.017 0.2934 0.2987
0.375 - 16 0.017 0.3514 0.3571
0.437 - 14 0.018 0.4091 0.4152
0.500 - 13 0.018 0.4680 0.4745
0.0562 - 12 0.020 0.5284 0.5352
0.625 - 11 0.020 0.5860 0.5932
0.750 - 10 0.020 0.7050 0.7127
0.875 - 9 0.022 0.8248 0.8330
Nominal Nut Size, in. and Pitch Diametral Allowance, in.
Pitch Diameter
Min Max
1.000 - 8 0.024 0.9428 0.9516
1.125 - 8 0.024 1.0678 1.0768
1.125 - 7 0.024 1.0562 1.0656
1.250 - 8 0.024 1.1928 1.2020
1.250 - 7 0.024 1.1812 1.1908
1.375 - 8 0.027 1.3208 1.3301
1.375 - 6 0.027 1.2937 1.3041
1.500 - 8 0.027 1.4458 1.4553
1.500 - 6 0.027 1.4187 1.4292
1.750 - 5 0.050 1.6701 1.6817
2.000 - 4.5 0.050 1.9057 1.9181
2.250 - 4.5 0.050 2.1557 2.1683
2.500 - 4 0.050 2.3876 2.4011
2.750 - 4 0.050 2.6376 2.6513
3.000 - 4 0.050 2.8876 2.9015
3.250 - 4 0.050 3.1376 3.1517
3.500 - 4 0.050 3.3876 3.4019
3.750 - 4 0.050 3.6376 3.6521
4.000 - 4 0.050 3.8876 3.9023
Inch Fastener Standards. 7th ed. Cleveland: Industrial Fasteners Institute, 2003. B-173.
ASTM F1554
Quick Links
Anchor Rods
ASTM A449
Strength by Grade
Scope
The ASTM F1554 specification was introduced in 1994 and covers anchor bolts designed to anchor structural supports to
concrete foundations. F1554 anchor bolts can take the form of either headed bolts, straight rods, or bent anchor bolts. The
three grades 36, 55, and 105 designate the minimum yield strength (ksi) of the anchor bolt. The bolts can be either cut or roll
threaded and a weldable grade 55 can be substituted for grade 36 at the supplier’s option. Color coding on the end - 36
blue, 55 yellow, and 105 red – helps facilitate easy identification in the field. Permanent manufacturer and grade marking is
allowed under the S2 supplementary requirements.
Applications for F1554 anchor bolts include columns in structural steel framed buildings, traffic signal and street lighting
poles, and overhead highway sign structures to name just a few.
Grades
F1554 Grade 36 Low carbon, 36 ksi yield steel anchor bolts
F1554 Grade 55 High strength, low alloy, 55 ksi yield steel anchor bolts
F1554 Grade 105 Alloy, heat treated, high strength 105 ksi yield steel anchor bolts
Mechanical Properties
Grade Marking Size
inches
Tensile,
ksi
Yield, ksi
min
Yield, MPa
min
Elong. %
min
RA %
min
36
1⁄4 - 4 58 - 80 36 248 23 40
55
1⁄4 - 2 75 - 95 55 380 21 30
21⁄4 - 21⁄2 75 - 95 55 380 21 22
23⁄4 - 3 75 - 95 55 380 21 20
31⁄4 - 4 75 - 95 55 380 21 18
105
1⁄4 - 3 125 - 150 105 724 15 45
Stamping of F1554 bolts with manufacturer's identification is a supplemental requirement (S2)
Color coding is required unless the grade is stamped in accordance with supplemental requirement (S3).
When Grade 36 is specified, a weldable Grade 55 may be furnished at the supplier's option.
Recommended Nuts and Washers
Grade Size inches Nuts
Washer Plain Galvanized
36
1⁄4 - 11⁄2 A563A Hex A563A Hex F436
13⁄4 - 4 A563A Heavy Hex A563A Heavy Hex F436
55
1⁄4 - 11⁄2 A563A Hex A563A Heavy Hex F436
13⁄4 - 4 A563A Heavy Hex A563A Heavy Hex F436
105
1⁄4 - 11⁄2 A563D Heavy Hex¹ A563DH Heavy Hex² F436
13⁄4 - 3 A563DH Heavy Hex² A563DH Heavy Hex² F436
1. A563-D rarely available, A563DH or A194-2H substituted. 2. Per ASTM A563, A194-2H may be substituted for A563-DH.
ASTM F2329
Quick Links
Galvanizing Capabilities
FAQ - Galvanizing High Strength
FAQ - Galvanized Nuts
Scope
ASTM F2329 covers the requirements for hot-dip zinc coating applied to carbon steel and alloy steel bolts, screws, washers,
nuts, and special threaded fasteners applied by the hot-dip coating process. This specification was developed in 2005, but
is not yet widely used since many of the ASTM specification covering threaded fasteners do not reference it. As soon as
these specifications are updated to reference the ASTM F2329 specification, it will likely become much more prevalent
than ASTM A153 which is the specification that is currently used to cover hot-dip galvanizing of bolts. ASTM A123 is a
related hot-dip galvanizing specification covering iron and steel products made from rolled pressed and forged shapes,
castings, plates, bars, and strips.
Galvanizing High Strength Bolts
Question: Can high strength bolts be hot-dip galvanized?
Answer: Some high strength bolts can be galvanized while others cannot. In the construction fastener industry, typically the
phrase “high strength” refers to bolts that have been quenched and tempered (heat treated) to develop the proper strength
requirements of a given specification. Two separate issues are involved in determining whether or not a high strength bolt
can be galvanized.
Hydrogen Embrittlement Concerns
The first issue involves a phenomenon called hydrogen embrittlement which may occur when atomic hydrogen is absorbed
by the steel during the acid pickling process that takes place prior to galvanizing. This embrittlement can potentially lead to
the loss or partial loss of ductility in the steel and consequently result in the premature failure of the fastener in the field.
According to specification ASTM A143 – Safeguarding Against Embrittlement of Hot-Dip Galvanized Structural Steel
Products and Procedure for Detecting Embrittlement:
“In practice hydrogen embrittlement of galvanized steel is usually of concern only if the steel exceeds approximately 150 ksi
(1100 MPa) in ultimate tensile strength.”
Additionally, section 7.2.2 of specification ASTM F2329 – Zinc Coating, Hot-Dip, Requirements for Application to Carbon
and Alloy Steel Bolts, Screws, Washers, Nuts, and Special Threaded Fasteners reads as follows:
“For high strength fasteners (having a specified minimum product hardness of 33 HRC), there is a risk of internal hydrogen
embrittlement.”
By reviewing Table 1 below, it is clear that specifications ASTM A490, ASTM A354 grade BD, and SAE J429 grade 8 are all
potentially susceptible to hydrogen embrittlement and should therefore not be hot-dip galvanized. This is further reinforced
by specific references found in both the ASTM A490 specification and the ASTM A354 specification. According to section
4.3 – Protective Coatings of specification ASTM A490:
“The bolts shall not be coated by hot-dip zinc coating, mechanical deposition, or electroplating with zinc or other metallic
coatings.”
Similarly, Note 4 in section 4 of specification ASTM A354 reads as follows:
“Research conducted on bolts of similar material and manufacture indicates that hydrogen-stress cracking or stress cracking
corrosion may occur on hot-dip galvanized Grade BD bolts.”
This information taken directly from the ASTM specifications supports the belief that hot-dip galvanizing of ASTM A490,
ASTM A354 grade BD, and SAE J429 grade 8 should be avoided due to the risk of hydrogen embrittlement.
Which Bolt Grades Can Be Galvanized?
Grade Can I
Galvanize?
Raw
material Nominal Size
Minimum
Yield
Strength
Minimum
Tensile
Strength
Minimum
Hardness
ASTM A325 Yes Medium
Carbon
Steel,
Quenched
and
Tempered
1/2″ – 1″
1 1/8″ – 1 1/2″
92
81
120
105
C24
C19
ASTM A449 Yes
1/4″ – 1″
1 1/8″ – 1 1/2″
1 5/8″ – 3″
92
81
58
120
105
90
C25
C19
B91
SAE J429 Grade 5 Yes 1/4″ – 1″
1 1/8″ – 1 1/2″
92
81
120
105
C25
C19
ASTM A193 Grade B7 Yes
Medium
Carbon Alloy
Steel,
Quenched
and
Tempered
1/4″ – 2 1/2″
2 5/8″ – 4″
105
95
125
115 NA
ASTM A354 Grade BC Yes 1/4″ – 2 1/2″
2 5/8″ – 4″
109
94
125
115
C26
C22
ASTM F1554 Grade
105 Yes 1/4″ – 3″ 105 125 NA
ASTM A320 Grade L7 Yes 1/4″ – 2 1/2″ 105 125 NA
ASTM A490 No 1/2″ – 1 1/2″ 130 150 C33
ASTM A354 Grade BD No 1/4″ – 2 1/2″
2 5/8″ – 4″
130
115
150
140
C33
C31
SAE J429 Grade 8 No 1/4″ – 1 1/2″ 130 150 C3
Effect of Heat on Quenched and Tempered Fasteners
The second issue of concern when considering hot-dip galvanizing high strength fasteners is potentially reducing the
mechanical strengths due to the introduction of heat during the hot-dip galvanizing process. Portland Bolt operates its hot-
dip galvanizing tank at 840° Fahrenheit. Is this enough heat to potentially alter the strength of a quenched and tempered
fastener? In theory, the amount of heat that a high strength fastener is exposed to during the hot-dip galvanizing process
should not alter its mechanical properties.
It is obvious that the application of heat to a bolt that develops its strength through a heat treating process could adversely
affect the strength of the fastener. The question is, how much heat is necessary to potentially change the mechanical
properties? On page 4-4 of the Ninth Edition of the AISC Manual (American Institute of Steel Construction), the following
statement occurs:
“Anchor bolt material that is quenched and tempered (heat treated) should not be welded or heated.”
However, it does not address the amount of heat that should be avoided. Welding obviously applies a tremendous amount
of heat to the components being welded, whereas hot-dip galvanizing is performed at significantly lower temperatures.
Another reference that addresses the heating of high strength bolts (which occurs during hot-dip galvanizing) can be found
in the ASTM F1554 specification. Section 6.4.3 of the ASTM F1554 specification states:
“Hot bending performed on heat-treated bar stock shall not have the temperature come within 100°F (56°C) of the tempering
(stress relieve) temperature of the heat-treat process at any location during hot bending and shall be allowed to air cool after
bending.”
Although this statement refers to hot bending, it implies that any process (including galvanizing) that applies heat
approaching or exceeding the tempering temperature of a high strength bolt may potentially alter the mechanical properties
of the fastener and should therefore be avoided. However, galvanized bolts only remain in the zinc tank for a few minutes
and even though the surface temperature may approach 840°, it is unlikely that the entire fastener is heated to that
temperature. The most relevant reference found in any ASTM specification addressing the possibility of the hot-dip
galvanizing process altering the mechanical properties of a high strength fastener is found in section 7.2.1.2 of the new hot-
dip galvanizing specification ASTM F2329 which states:
“Testing for mechanical properties is not necessary if the galvanizing process is carried out at a lower temperature than the
stress relief or tempering temperature of the fasteners.”
This implies that the mechanical properties have the potential to be altered only if high strength bolts are tempered at
temperatures at or below the 840° temperature that the bolts are subjected to during hot-dip galvanizing. As Table 2
indicates below, the minimum tempering temperature for both ASTM A193 grade B7 and ASTM F1554 grade 105 is 1100°
Fahrenheit. Therefore, it is not possible for the galvanizing temperatures to exceed the tempering temperature for these
specifications. Although in theory it is possible for the other specifications to be tempered below the galvanizing
temperature, recent records indicate that the minimum tempering temperature used for any of these grades listed in Table 2
that Portland Bolt has manufactured is 950°. Therefore, hot-dip galvanizing performed by Portland Bolt on any of the high
strength bolt specifications listed in Table 2 will not adversely affect the strength of these fasteners.
Minimum Tempering Temperatures
ASTM Grade Minimum Tempering Temperature, Fahrenheit
A325 800°
A449 800°
A354 Grade BC 800°
A320 Grade L7 No Requirement
A193 Grade B7 1100°
F1554 Grade 105 1100°