ASTM A563 Specification

This specification2 covers chemical, mechanical, and dimensional requirements for eleven grades of carbon and alloy steel nuts for general structural and mechanical uses on bolts, studs, and other externally threaded parts.

ASTM A563

Chemical Requirements

Nut Grade 8S 8S3 D 10S 10S3
Heat Analysis Composition % Composition
A %		 Composition
B %		 Based on Corrosion IndexC Composition % Composition % Based on Corrosion IndexC
Carbon 0.55 max 0.33-0.40 0.38-0.48 0.30-0.53 0.55 max 0.20-0.55 0.20-0.53 0.30-0.53
Manganese B 0.90-1.20 0.70-0.90 0.60 min 0.30 min 0.60 min 0.40 min 0.60 min
Phosphorus, max 0.12 0.035 0.035 0.035 0.04 0.04 0.035 0.035
Sulfur, max 0.15D 0.040 0.040 0.040 0.05E 0.05E 0.040 0.040
Silicon B 0.15-0.35 0.30-0.50 B B B B B
Copper B 0.25-0.45 0.20-0.40 0.20-0.60 B B 0.20 min 0.20-0.60
Nickel B 0.25-0.45 0.50-0.80 0.20F min B B 0.20F min 0.20F min
Chromium B 0.45-0.65 0.50-0.75 0.45 min B B 0.45 min 0.45 min
Vanadium B B B B B B B B
Molybdenum B B 0.06 max 0.10F min B B 0.15F min 0.10F min
Titanium B B B B B B B B

Hardness Requirements

Grade of Nut Nominal Nut Size Hardness
Brinell Rockwell
min max min max
A #6(0.138) to 4 in. 116 302 B68 C32
B #6(0.138) to 1 ½ in. 121 302 B69 C32
C and C3 ½ to 4 in. 143 352 B78 C38
D ¼ to 4 in. 159 352 B84 C38
DH #6(0.138) to 4 in. 248 352 C24 C38
DH3 ½ to 4 in. 248 352 C24 C38

Proof Load Requirements

Grade of Nut Nominal Nut Size, in. Proof Load Stress, ksiA,G
Non-Overtapped B Overtapped B Non-Overtapped B Overtapped B
Square
A ¼ to 1½ 90 68 100 75
BF ¼ to 1 105 79 133 100
BF 1⅛ to 1½ 92 70 116 87
DH ¼ to 1½ 132 100 165 123
Hex
A ¼ to 4 90 68 100 75
BF ¼ to 1 120 90 133 100
BF 1⅛ to 1½ 105 79 116 87
CC ½ to 4 130 . . . 144 . . .
C3 ½ to 4 . . . . . . 144 . . .
DC ¼ to 4 135 . . . 150 . . .
DHD ¼ to 4 150 115 175 150E
DH3 ¼ to 4 150 . . . 175 150E
Hex Thick
A ¼ to 1½ 100 75
BF ¼ to 1 133 100
BF 1⅛ to 1½ 116 87
DHD ¼ to 1½ 175 150
Hex Flange
A #6 to ¾ 90 68
BF #6 to ¾ 120 90
DHD #6 to ¾ 150 115
Nuts with UNF, 12 UN, and Finer Pitch Threads
Grade of Nut Nominal Nut Size, in. Proof Load Stress, ksiG
Non-OvertappedB OvertappedB Non-OvertappedB OvertappedB
Square
A ¼ to 1½ 80 60 90 68
BF ¼ to 1 96 72 116 87
BF 1⅛ to 1½ 84 63 105 78
DHD ¼ to 1½ 132 99 165 123
Hex
A ¼ to 4 80 60 90 68
BF ¼ to 1 109 82 120 90
BF 1⅛ to 1½ 94 70 105 79
CC ½ to 4 . . . . . . . . . . . .
DC ¼ to 4 135 . . . 150 . . .
DHD ¼ to 4 150 115 175 150
Hex Thick
A ¼ to 1½ 90 68
BF ¼ to 1 120 90
BF 1⅛ to 1½ 105 70
DHD ¼ to 1½ 175 150
Hex Flange
A #6 to ¾ 80 60
BF #6 to ¾ 109 82
DHD #6 to ¾ 150 115

Tensile Stress Areas—Inch

Nominal Size–
Threads
per Inch		 UNC
Tensile Stress
Area, As in.2		 Nominal Size–
Threads
per Inch		 UNF
Tensile Stress
AreaA As in.2		 Nominal Size–
Threads
per Inch		 8 UN
Tensile Stress
AreaA, As in.2
#6–32 0.00909 #6–40 0.01015
#8–32 0.0140 #8–36 0.01474
#10–24 0.0175 #10–32 0.0200
#12–24 0.0242 #12–28 0.0258
¼–20 0.0318 ¼–28 0.0364 ... ...
5⁄16–18 0.0524 5⁄16–24 0.0580 ... ...
3⁄8–16 0.0775 3⁄8–24 0.0878 ... ...
7⁄16–14 0.1063 7⁄16–20 0.1187 ... ...
½–13 0.1419 ½–20 0.1599 ... ...
9⁄16–12 0.182 9⁄16–18 0.203 ... ...
5⁄8–11 0.226 5⁄8–18 0.256 ... ...
¾–10 0.334 ¾–16 0.373 ... ...
⅞–9 0.462 ⅞–14 0.509 ... ...
1–8 0.606 1–12 0.663 1–8 0.606
1⅛–7 0.763 1⅛–12 0.856 1⅛–8 0.790
1¼–7 0.969 1¼–12 1.073 1¼–8 1.000
1⅜–6 1.155 1⅜–12 1.315 1⅜–8 1.233
1½–6 1.405 1½–12 1.581 1½–8 1.492
1¾–5 1.90 ... ... 1¾–8 2.08
2–4½ 2.50 ... ... 2–8 2.77
2¼–4½ 3.25 ... ... 2¼–8 3.56
2½–4 4.00 ... ... 2½–8 4.44
2¾–4 4.93 ... ... 2¾–8 5.43
3–4 5.97 ... ... 3–8 6.51
3¼–4 7.10 ... ... 3¼–8 7.69
3½–4 8.33 ... ... 3½–8 8.96
3¾–4 9.66 ... ... 3¾–8 10.34
4–4 11.08 ... ... 4–8 11.81

AAs The inch stress area is calculated as follows:

As = 0.7854 (D − (0.9743 / n))2

where: As = stress area, in.2, D = nominal size, (in.), and n = threads per in.

Thread Dimensions and Overtapping Allowances for Coated Nuts

Nominal Nut
Size, in. and
Pitch 		Galvanized F2329/F2329M/B695 Zn/Al Coatings F3393B
Diametral
Allowance,
in.A 		Pitch Diameter, in.
min max
Diametral
Allowance,
in.A 		Pitch Diameter, in.
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 0.009 0.4590 0.4655
0.562-12 0.020 0.5284 0.5352
0.625-11 0.020 0.5860 0.5932 0.010 0.5760 0.5832
0.750-10 0.020 0.7050 0.7127 0.010 0.6950 0.7027
0.875-9 0.022 0.8248 0.8330 0.011 0.8138 0.8220
1.000-8 0.024 0.9428 0.9516 0.012 0.9308 0.9396
1.125-8 0.024 1.0678 1.0768
1.125-7 0.024 1.0562 1.0656 0.012 1.0442 1.0536
1.250-8 0.024 1.1928 1.2020
1.250-7 0.024 1.1812 1.1908 0.012 1.1692 1.1888
1.375-8 0.027 1.3208 1.3301
1.375-6 0.027 1.2937 1.3041 0.014 1.2807 1.2911
1.500-8 0.027 1.4458 1.4553
1.500-6 0.027 1.4187 1.4292 0.014 1.4057 1.4162
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
3.750-4 0.050 3.6376 3.6521
4.000-4 0.050 3.8876 3.9023

A These allowances also apply to the minimum and maximum major and minor diameters.

B Zn/Al allowances apply to nuts used with F3125/F3125M bolts. Guidance for other applications is provided in F3393.

Referenced Documents

A194/A194M Specification for Carbon Steel, Alloy Steel, and Stainless Steel Nuts for Bolts for High Pressure or High Temperature Service, or Both

A307 Specification for Carbon Steel Bolts, Studs, and Threaded Rod 60 000 PSI Tensile Strength

A354 Specification for Quenched and Tempered Alloy Steel Bolts, Studs, and Other Externally Threaded Fasteners

A394 Specification for Steel Transmission Tower Bolts, Zinc-Coated and Bare

A449 Specification for Hex Cap Screws, Bolts and Studs, Steel, Heat Treated, 120/105/90 ksi Minimum Tensile Strength, General Use

A751 Test Methods and Practices for Chemical Analysis of Steel Products

B695 Specification for Coatings of Zinc Mechanically Deposited on Iron and Steel

F606/F606M Test Methods for Determining the Mechanical Properties of Externally and Internally Threaded Fasteners, Washers, Direct Tension Indicators, and Rivets

F812 Specification for Surface Discontinuities of Nuts, Inch and Metric Series

F1136/ F1136M Specification for Zinc/Aluminum Corrosion Protective Coatings for Fasteners

F1470 Practice for Fastener Sampling for Specified Mechanical Properties and Performance Inspection

F1554 Specification for Anchor Bolts, Steel, 36, 55, and 105-ksi Yield Strength

F1789 Terminology for F16 Mechanical Fasteners

F1941 /F1941M Specification for Electrodeposited Coatings on Mechanical Fasteners, Inch and Metric

F2329/F2329M Specification for Zinc Coating, Hot-Dip, Requirements for Application to Carbon and Alloy Steel Bolts, Screws, Washers, Nuts, and Special Threaded Fasteners

F2833 Specification for Corrosion Protective Fastener Coatings with Zinc Rich Base Coat and Aluminum Organic Topcoat Type

F3019/F3019M Specification for Chromium Free Zinc-Flake Composite, with or without Integral Lubricant, Corrosion Protective Coatings for Fasteners

F3125/F3125M Specification for High Strength Structural Bolts and Assemblies, Steel and Alloy Steel, Heat Treated, Inch Dimensions 120 ksi and 150 ksi Minimum Tensile Strength, and Metric Dimensions 830 MPa and 1040 MPa Minimum Tensile Strength

F3148 Specification for High Strength Structural Bolt Assemblies, Steel and Alloy Steel, Heat Treated, 144 ksi Minimum Tensile Strength, Inch Dimensions

F3393 Specification for Zinc-Flake Coating Systems for Fasteners

G101 Guide for Estimating the Atmospheric Corrosion Resistance of Low-Alloy Steels

ASME Standards:

ASME B1.1 Unified Screw Threads

ASME B18.2.2 Square and Hex Nuts

ASME B18.2.6 Fasteners for Use in Structural Applications

ASME B18.2.6M Metric Fasteners for Use in Structural Applications

ASME B1.13M Metric Screw Threads-M Profile

SAE Standard:

SAE J995 Mechanical and Material Requirements for Steel Nuts