Scope
1.1 This specification covers chemical and mechanical requirements for eight grades of carbon and alloy steel nuts for general structural and mechanical uses on bolts, studs and other externally threaded parts.
1.3 Grades C3 and DH3 nuts have atmospheric corrosion resistance and weathering characteristics comparable to that of the steels covered in Specifications A242, A588 & A709. The atmospheric corrosion resistance of these steels is substantially better than that of carbon steel with or without copper addition. When properly exposed to the atmosphere, these steels can be used bare (uncoated) for many applications.
Table 1: Chemical Requirements for Grades O, A, B, C, D and DH Nuts
Grade | Analysis | Carbon | Manganese, min | Phophorus, max | Sulfur, max |
O,A,B,C | Heat | 0.55 max | - | 0.12 | 0.15 ᴬ |
| Product | 0.58 max | - | 0.13 ᴮ | - |
D ᶜ | Heat | 0.55 max | 0.3 | 0.04 | 0.05 |
| Product | 0.58 max | 0.27 | 0.048 | 0.058 |
DH ᶜ | Heat | 0.20-0.55 | 0.6 | 0.04 | 0.05 |
| Product | 0.18-0.58 | 0.57 | 0.048 | 0.058 |
Source: ASTM A563-15 |
Table 2: Chemical Requirements for Grades C3 and DH3 Nuts
Element | Analysis | Classes for Grade C3 Nuts ᴬ | Grade |
| | N | A | B | C | D | E | F | DH3 Nuts |
Carbon | Heat | - | 0.33 - 0.40 | 0.38 - 0.48 | 0.15 - 0.25 | 0.15 - 0.25 | 0.20 - 0.25 | 0.20 - 0.25 | 0.20 - 0.53 |
| Product | - | 0.31 - 0.42 | 0.36 - 0.50 | 0.14 - 0.26 | 0.14 - 0.26 | 0.18 - 0.27 | 0.19 - 0.26 | 0.19 - 0.55 |
Manganese | Heat | - | 0.90 - 1.20 | 0.70 - 0.90 | 0.80 - 1.35 | 0.40 - 1.20 | 0.60 - 1.00 | 0.90 - 1.20 | 0.40 min |
| Product | - | 0.86 - 1.24 | 0.67 - 0.93 | 0.76 - 1.39 | 0.36 - 1.24 | 0.56 - 1.04 | 0.86 - 1.24 | 0.37 min |
Phosphorus | Heat | 0.07 - 0.15 | 0.040 max | 0.06 - 0.12 | 0.035 max | 0.040 max | 0.040 max | 0.040 max | 0.046 max |
| Product | 0.07 - 0.155 | 0.045 max | 0.06 - 0.125 | 0.040 max | 0.045 max | 0.045 max | 0.045 max | 0.052 max |
Sulfur | Heat | 0.050 max | 0.050 max | 0.050 max | 0.040 max | 0.050 max | 0.040 max | 0.040 max | 0.050 max |
| Product | 0.055 max | 0.055 max | 0.055 max | 0.045 max | 0.055 max | 0.045 max | 0.045 max | 0.055 max |
Silicon | Heat | 0.20 - 0.90 | 0.15 - 0.35 | 0.30 - 0.50 | 0.15 - 0.35 | 0.25 - 0.50 | 0.15 - 0.35 | 0.15 - 0.35 | - |
| Product | 0.15 - 0.95 | 0.13 - 0.37 | 0.13 - 0.37 | 0.13 - 0.37 | 0.20 - 0.55 | 0.13 - 0.37 | 0.13 - 0.37 | - |
Copper | Heat | 0.25 - 0.55 | 0.25 - 0.45 | 0.20 - 0.40 | 0.20 - 0.50 | 0.30 - 0.50 | 0.30 - 0.60 | 0.20 - 0.40 | 0.20 min |
| Product | 0.22 - 0.58 | 0.22 - 0.48 | 0.17 - 0.43 | 0.17 - 0.53 | 0.27 - 0.53 | 0.27 - 0.63 | 0.17 - 0.43 | 0.17 min |
Nickel | Heat | 1.00 max | 0.25 - 0.45 | 0.50 - 0.80 | 0.25 - 0.50 | 0.50 - 0.80 | 0.30 - 0.60 | 0.45 - 0.65 | 0.20 min ᴮ |
| Product | 1.03 max | 0.22 - 0.48 | 0.47 - 0.83 | 0.22 - 0.53 | 0.47 - 0.83 | 0.27 - 0.63 | 0.42 0.68 | 0.17 min |
Chromium | Heat | 0.30 - 1.25 | 0.45 - 0.65 | 0.50 - 0.75 | 0.30 - 0.50 | 0.50 - 1.00 | 0.60 - 0.90 | 0.45 - 0.65 | 0.45 min |
| Product | 0.25 - 1.30 | 0.52 - 0.68 | 0.74 - 0.83 | 0.27 - 0.53 | 0.45 -1.05 | 0.55 - 0.95 | 0.42 - 0.68 | 0.42 min |
Vanadium | Heat | - | - | - | 0.020 min | - | - | - | - |
| Product | - | - | - | 0.010 min | - | - | - | - |
Molybdenum | Heat | - | - | 0.06 max | - | 0.10 max | - | - | 0.15 min ᴮ |
| Product | - | - | 0.07 max | - | 0.11 max | - | - | 0.14 min |
Titanium | Heat | - | - | - | - | 0.05 max | - | - | - |
| Product | - | - | - | - | - | - | - | - |
Source: ASTM A563-15 |
Table 3 Mechanical Requirements for Nuts with UNC & 8 UN Threads
Grade of Nut | Nominal Size | Style | Proof Load Stress, ksi ᴬ | Brinell Hardness | Rockwell Hardness |
| | | Non Zinc Coated ᴮ | Zinc Coated ᴮ | min | max | min | max |
O | 1/4" to 1-1/2" | square | 69 | 52 | 103 | 302 | B55 | C32 |
A | 1/4" to 1-1/2" | square | 90 | 68 | 116 | 302 | B68 | C32 |
A | 1/4" to 1-1/2" | Hex | 90 | 68 | 116 | 302 | B68 | C32 |
B | 1/4" to 1" | Hex | 120 | 90 | 121 | 302 | B69 | C32 |
B | 1-1/8" to 1-1/2" | Hex | 105 | 79 | 121 | 302 | B69 | C32 |
C | 1/4" to 1-1/2" | Hex | 130 | 130 | 143 | 352 | B78 | C38 |
D ᶜ | 1/4" to 1-1/2" | Hex | 135 | 135 | 159 | 352 | B84 | C38 |
DH ᴰ | 1/4" to 1-1/2" | Hex | 150 | 150 | 248 | 352 | C24 | C38 |
DH3 | 1/2" to 1" | Hex | 150 | 150 | 248 | 352 | C24 | C38 |
A | 1/4" to 4" | Heavy Hex | 100 | 75 | 116 | 302 | B68 | C32 |
B | 1/4" to 1" | Heavy Hex | 133 | 100 | 121 | 302 | B69 | C32 |
B | 1-1/8" to 1-1/2" | Heavy Hex | 116 | 87 | 121 | 302 | B69 | C32 |
C ᶜ | 1/4" to 4" | Heavy Hex | 144 | 144 | 143 | 352 | B78 | C38 |
C3 | 1/4" to 4" | Heavy Hex | 144 | 144 | 143 | 352 | B78 | C38 |
D ᶜ | 1/4" to 4" | Heavy Hex | 150 | 150 | 159 | 352 | B84 | C38 |
DH ᴰ | 1/4" to 4" | Heavy Hex | 175 | 150 | 248 | 352 | C24 | C38 |
DH3 | 1/4" to 4" | Heavy Hex | 175 | 150 | 248 | 352 | C24 | C38 |
Source: ASTM A563-15 |
A: To determine nut proof load in pounds, multiply the appropriate nut proof load stress by the tensile stress area of the thread. Stress areas for UNC and 8 UN thread series are given in Table 4.
B: Non-zinc-coated nuts are nuts intended for use with externally threaded fasteners which have a plain (non-plated or non-coated) finish or have a plating or coating of insufficient thickness to necessitate overtapping the nut thread to provide assemblability. Zinc-coated nuts are nuts intended for use with externally threaded fasteners which are hot-dip zinc-coated, mechanically zinc-coated, or have a plating or coating of sufficient thickness to necessitate overtapping the nut thread to provide assemblability.
C: Nuts made in accordance to the requirements of Specification A194, Grade 2 or Grade 2H, and marked with their grade symbol are acceptable equivalents for Grades C and D nuts. When A194 zinc-coated inch series nuts are supplied, the zinc coating, overtapping, lubrication and rotational capacity testing shall be in accordance with Specification A563.
D: Nuts made in accordance with the requirements of Specification A194, Grade 2H, and marked with its grade symbol are an acceptable equivalent for Grade DH nuts. When A194 zinc-coated inch series nuts are supplied, the zinc coating, overtapping, lubrication and rotational capacity testing shall be in accordance with Specification A563.
Table 4 Tensile Stress Areas
UNC | 8 UN |
Nominal Dia. | Threads per Inch | Tensile Stress Area, ᴬ in.₂ | Nominal Dia. | Threads per Inch | Tensile Stress Area, ᴬ in.₂ |
1/4" | 20 | 0.0318 | - | - | - |
5/16" | 18 | 0.0524 | - | - | - |
3/8" | 16 | 0.0775 | - | - | - |
7/16" | 14 | 0.1063 | - | - | - |
1/2" | 13 | 0.1419 | - | - | - |
9/16" | 12 | 0.182 | - | - | - |
5/8" | 11 | 0.226 | - | - | - |
3/4" | 10 | 0.334 | - | - | - |
7/8" | 9 | 0.462 | - | - | - |
1" | 8 | 0.606 | 1" | 8 | 0.606 |
1-1/8" | 7 | 0.763 | 1-1/8" | 8 | 0.79 |
1-1/4" | 7 | 0.969 | 1-1/4" | 8 | 1 |
1-3/8" | 6 | 1.155 | 1-3/8" | 8 | 1.233 |
1-1/2" | 6 | 1.405 | 1-1/2" | 8 | 1.492 |
1-3/4" | 5 | 1.9 | 1-3/4" | 8 | 2.08 |
2" | 4.5 | 2.5 | 2" | 8 | 2.77 |
2-1/4" | 4.5 | 3.25 | 2-1/4" | 8 | 3.56 |
2-1/2" | 4 | 4 | 2-1/2" | 8 | 4.44 |
2-3/4" | 4 | 4.93 | 2-3/4" | 8 | 5.43 |
3" | 4 | 5.97 | 3" | 8 | 6.51 |
3-1/4" | 4 | 7.1 | 3-1/4" | 8 | 7.69 |
3-1/2" | 4 | 8.33 | 3-1/2" | 8 | 8.96 |
3-3/4" | 4 | 9.66 | 3-3/4" | 8 | 10.34 |
4" | 4 | 11.08 | 4" | 8 | 11.81 |
Source: ASTM A563-15 |
As The 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 inch.
Table 5 Thread Dimensions and Overtapping Allowances for Nuts Hot Dip Zinc Coated per F2329
Nominal Nut Size, in. | Threads per Inch | Diametral Allowance, in. ᴬ | Pitch Diameter, in |
| | | min | max |
0.25 | 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 |
0.5 | 13 | 0.018 | 0.468 | 0.4745 |
0.562 | 12 | 0.02 | 0.5284 | 0.5352 |
0.625 | 11 | 0.02 | 0.586 | 0.5932 |
0.75 | 10 | 0.02 | 0.705 | 0.7127 |
0.875 | 9 | 0.022 | 0.8248 | 0.833 |
1 | 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 |
1.25 | 8 | 0.024 | 1.1928 | 1.202 |
1.25 | 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 |
1.5 | 8 | 0.027 | 1.4458 | 1.4553 |
1.5 | 6 | 0.0274 | 1.4187 | 1.4292 |
1.75 | 5 | 0.05 | 1.6701 | 1.6817 |
2 | 4.5 | 0.05 | 1.9057 | 1.9181 |
2.25 | 4.5 | 0.05 | 2.1557 | 2.1683 |
2.5 | 4 | 0.05 | 2.3876 | 2.4011 |
2.75 | 4 | 0.05 | 2.6376 | 2.6513 |
3 | 4 | 0.05 | 2.8876 | 2.9015 |
3.325 | 4 | 0.05 | 3.1376 | 3.1517 |
3.5 | 4 | 0.05 | 3.3876 | 3.4019 |
3.75 | 4 | 0.05 | 3.6376 | 3.6521 |
3.75 | 4 | 0.05 | 3.6376 | 3.6521 |
4 | 4 | 0.05 | 3.8876 | 3.9023 |
Source: ASTM A563-15 |
A – These allowances also apply to the minimum and maximum major and minor diameters.
Table X1.1 Nut Suitability Chart
Grade of Bolt | Finish | Nominal Size | A563 Grade and ANSI Nut Style |
| | | Recommended | Suitable |
Hex | Heavy Hex | Hex | Heavy Hex |
A307 Grade A & C | Any | 1/4 to 1-1/2 | A | - | B,D,DH | A,B,C,D,DH,DH3 |
A307 Grade A & C | Any | >1-1/2 to 2 | - | A | A | C,D,DH,DH3 |
A307 Grade A & C | Any | >2 to 4 | - | A | - | C,D,DH,DH3 |
A307 Grade B | Any | 1/4 to 1-1/2 | - | A | B,D,DH | B,C,D,DH,DH3 |
A307 Grade B | Any | >1-1/2 to 2 | - | A | A | - |
A307 Grade B | Any | >2 to 4 | - | A | - | - |
A325 Type 1 | Plain | 1/2 - 1-1/2 | - | C | - | C3, D, DH, DH3 |
A325 Type 1 | Galvanized | 1/2 - 1-1/2 | - | DH | - | - |
A325 Type 3 | Plain | 1/2 - 1-1/2 | - | C3 | - | DH3 |
A354 Grade BC | Plain | 1/4 to 1-1/2 | - | C | - | C3, D, DH, DH3 |
A354 Grade BC | Plain | >1-1/2 to 4 | - | C | - | C3, D, DH, DH3 |
A354 Grade BC | Galvanized | 1/4 to 1-1/2 | - | DH | - | - |
A354 Grade BC | Galvanized | >1-1/2 to 4 | - | DH | - | - |
A354 Grade BD | Plain | 1/4 to 1-1/2 | - | DH | - | D, DH, DH3 |
A354 Grade BD | Plain | >1-1/2 to 4 | - | DH | - | DH3 |
A449 | Plain | 1/4 to 1-1/2 | B | - | D, DH | B,C,D,DH,DH3 |
A449 | Plain | >1-1/2 to 3 | - | A | - | C,C3,D,DH,DH3 |
A449 | Galvanized | 1/4 to 1-1/2 | - | DH | D, DH | D |
A449 | Galvanized | >1-1/2 to 3 | - | DH | - | D |
A490 Type 1 | Plain | 1/2 - 1-1/2 | - | DH | - | DH3 |
A490 Type 3 | Plain | 1/2 - 1-1/2 | - | DH3 | - | - |
A687 | Plain | 5/8 - 3 | - | DH | - | DH, DH3 |
A687 | Galvanized | 5/8 - 3 | - | DH3 | - | - |
F1554 Grade 55 | Plain | 1/4 to 1-1/2 | A | - | B,D,DH | A,B,C,D,DH,DH3 |
F1554 Grade 55 | Plain | >1-1/2 to 4 | - | A | - | C,D,DH,DH3 |
F1554 Grade 55 | Galvanized | 1/4 to 4 | - | A | - | C,D,DH,DH3 |
F1554 Grade 105 | Plain | 1/4 to 1-1/2 | D | - | - | DH, DH3 |
F1554 Grade 105 | Plain | >1-1/2 to 3 | - | DH | - | DH3 |
F1554 Grade 105 | Galvanized | 1/4 to 3 | - | DH | - | DH3 |
Source: ASTM A563-15 Appendix X1 |