Related Specifications
Surface Treatments
Certifications
- ISO 9001 - 2015 Certified
- PED 2014/68/EC
- NACE MR0175/ISO 15156-2
- NORSOK M-650
- DFAR
- MERKBLATT AD 2000 W2/W7/W10
B18.31.2 Inch Double End Stud Bolts Dimensions
ASME B18.31.2 standard covering continuous thread double end studs for high-pressure flange applications
B18.31.2 Inch Double End Stud Bolts Dimension Standard define standard thread lengths, diameters, and tolerances used in flange connections and pressure vessels. These studs ensure uniform load distribution and are widely used in oil & gas, petrochemical, and power industries.
ASME B18.31.2 Inch Double End Stud Bolts Dimensions
| Nominal Size |
Diameter, D | Nut End Minimum Full Thread
Length, Bmin |
Minimum Body Diameter, DS | ||||
|---|---|---|---|---|---|---|---|
| L ≤ 254 mm (10 in) |
254 < L ≤ 406.4 mm (10 < L ≤ 16 in) |
L > 406.4 mm (16 in) |
UNC and NC-5 HF Threads |
UNF Threads |
8UN Threads |
||
| ¼ | 6.350 | 19.050 | 25.400 | 38.100 | 6.121 | 6.172 | … |
| 5/16 | 7.938 | 22.225 | 28.575 | 41.275 | 7.696 | 7.722 | … |
| 3/8 | 9.525 | 25.400 | 31.750 | 44.450 | 9.246 | 9.322 | … |
| 7/16 | 11.113 | 28.575 | 34.925 | 47.625 | 10.820 | 10.871 | … |
| ½ | 12.700 | 31.750 | 38.100 | 50.800 | 12.395 | 12.471 | … |
| 9/16 | 14.288 | 34.925 | 41.275 | 53.975 | 13.970 | 14.021 | … |
| 5/8 | 15.875 | 38.100 | 44.450 | 57.150 | 15.519 | 15.621 | … |
| ¾ | 19.050 | 44.450 | 50.800 | 63.500 | 18.669 | 18.771 | … |
| 7/8 | 22.225 | 50.800 | 57.150 | 69.850 | 21.819 | 21.920 | … |
| 1 | 25.400 | 57.150 | 63.500 | 76.200 | 24.968 | 25.070 | … |
| 1⅛ | 28.575 | 63.500 | 69.850 | 82.550 | 28.092 | 28.245 | 28.143 |
| 1¼ | 31.750 | 69.850 | 76.200 | 88.900 | 31.267 | 31.420 | 31.318 |
| 1⅜ | 34.925 | 76.200 | 82.550 | 95.250 | 34.392 | 34.595 | 34.493 |
| 1½ | 38.100 | 82.550 | 88.900 | 101.600 | 37.567 | 37.770 | 37.668 |
| 1⅝ | 41.275 | 88.900 | 95.250 | 107.950 | … | … | 40.843 |
| 1¾ | 44.450 | 95.250 | 101.600 | 114.300 | 43.866 | … | 44.018 |
| 1⅞ | 47.625 | 101.600 | 107.950 | 120.650 | … | … | 47.193 |
| 2 | 50.800 | 107.950 | 114.300 | 127.000 | 50.165 | … | 50.368 |
| 2¼ | 57.150 | 120.650 | 127.000 | 139.700 | 56.515 | … | 56.718 |
| 2½ | 63.500 | 133.350 | 139.700 | 152.400 | 62.814 | … | 63.068 |
| 2¾ | 69.850 | 146.050 | 152.400 | 165.100 | 69.164 | … | 69.418 |
| 3 | 76.200 | ... | 165.100 | 177.800 | 75.514 | … | 75.743 |
| 3¼ | 82.550 | ... | 177.800 | 190.500 | 81.864 | … | 82.093 |
| 3½ | 88.900 | ... | 190.500 | 203.200 | 88.214 | … | 88.443 |
| 3¾ | 95.250 | ... | 203.200 | 215.900 | 94.564 | … | 94.793 |
| 4 | 101.600 | ... | 215.900 | 228.600 | 100.914 | … | 101.143 |
ASME B18.31.2 Inch Double End Stud Bolts Length Tolerances
| Range, LT | Tolerance |
|---|---|
| From 19.05 through 63.5 | ±1.016 |
| Over 63.5 through 101.6 | ±2.032 |
| Over 101.6 through 203.2 | ±2.540 |
| Over 203.2 through 406.4 | ±3.048 |
| Over 406.4 | ±4.572 |
ASME B18.31.2 Inch Double End Stud Bolts Dimensions (Inch)
| Nominal Size |
Diameter, D |
Nut End Minimum Full Thread
Length, Bmin |
Minimum Body Diameter, DS | ||||
|---|---|---|---|---|---|---|---|
| L ≤ 10 | 10 < L ≤ 16 | L > 16 | UNC and NC-5 HF Threads |
UNF Threads |
8UN Threads |
||
| ¼ | 0.2500 | 0.750 | 1.000 | 1.500 | 0.241 | 0.243 | … |
| 5/16 | 0.3125 | 0.875 | 1.125 | 1.625 | 0.303 | 0.304 | … |
| 3/8 | 0.3750 | 1.000 | 1.250 | 1.750 | 0.364 | 0.367 | … |
| 7/16 | 0.4375 | 1.125 | 1.375 | 1.875 | 0.426 | 0.428 | … |
| ½ | 0.5000 | 1.250 | 1.500 | 2.000 | 0.488 | 0.491 | … |
| 9/16 | 0.5625 | 1.375 | 1.625 | 2.125 | 0.550 | 0.552 | … |
| 5/8 | 0.6250 | 1.500 | 1.750 | 2.250 | 0.611 | 0.615 | … |
| ¾ | 0.7500 | 1.750 | 2.000 | 2.500 | 0.735 | 0.739 | … |
| 7/8 | 0.8750 | 2.000 | 2.250 | 2.750 | 0.859 | 0.863 | … |
| 1 | 1.0000 | 2.250 | 2.500 | 3.000 | 0.983 | 0.987 | … |
| 1⅛ | 1.1250 | 2.500 | 2.750 | 3.250 | 1.106 | 1.112 | 1.108 |
| 1¼ | 1.2500 | 2.750 | 3.000 | 3.500 | 1.231 | 1.237 | 1.233 |
| 1⅜ | 1.3750 | 3.000 | 3.250 | 3.750 | 1.354 | 1.362 | 1.358 |
| 1½ | 1.5000 | 3.250 | 3.500 | 4.000 | 1.479 | 1.487 | 1.483 |
| 1⅝ | 1.6250 | 3.500 | 3.750 | 4.250 | … | … | 1.608 |
| 1¾ | 1.7500 | 3.750 | 4.000 | 4.500 | 1.727 | … | 1.733 |
| 1⅞ | 1.8750 | 4.000 | 4.250 | 4.750 | … | … | 1.858 |
| 2 | 2.0000 | 4.250 | 4.500 | 5.000 | 1.975 | … | 1.983 |
| 2¼ | 2.2500 | 4.750 | 5.000 | 5.500 | 2.225 | … | 2.233 |
| 2½ | 2.5000 | 5.250 | 5.500 | 6.000 | 2.473 | … | 2.483 |
| 2¾ | 2.7500 | 5.750 | 6.000 | 6.500 | 2.723 | … | 2.733 |
| 3 | 3.0000 | ... | 6.500 | 7.000 | 2.973 | … | 2.982 |
| 3¼ | 3.2500 | ... | 7.000 | 7.500 | 3.223 | … | 3.232 |
| 3½ | 3.5000 | ... | 7.500 | 8.000 | 3.473 | … | 3.482 |
| 3¾ | 3.7500 | ... | 8.000 | 8.500 | 3.723 | … | 3.732 |
| 4 | 4.0000 | ... | 8.500 | 9.000 | 3.973 | … | 3.982 |
ASME B18.31.2 Inch Double End Stud Bolts Length Tolerances (Inch)
| Range, LT | Tolerance |
|---|---|
| From ¾ through 2½ | ±0.04 |
| Over 2½ through 4 | ±0.08 |
| Over 4 through 8 | ±0.10 |
| Over 8 through 16 | ±0.12 |
| Over 16 | ±0.18 |
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