Continuously Threaded Inch-Series Stud Bolts for Pipe Flange Bolting in Oil & Gas, Chemical, and Process Piping Systems.
ASME B16.5 Full Thread Stud Bolts are continuously threaded inch-series stud fasteners, threaded from end to end with no unthreaded shank , one of the flange bolting options permitted by ASME B16.5 (stud bolts threaded at both ends or full length, or bolts) for pipe flange joints, where their continuous thread allows precise length adjustment to accommodate varying flange thicknesses, insulating gasket kits, orifice flange unions, and different gasket types across flange Classes 150 through 1500 in NPS 1/2 through NPS 24 and Class 2500 in NPS 1/2 through NPS 12. ASME B16.5 tabulates bolt diameter and a reference stud bolt length L for each flange size and pressure class, calculated per Nonmandatory Appendix C to give full thread engagement of the heavy hex nuts under worst-case tolerances; the tabulated lengths are reference dimensions and users may select other lengths. When manufactured to ASTM A1082, the specification for high-strength stainless steel bolting material, these full thread stud bolts provide excellent corrosion resistance in aggressive service environments, including offshore topsides and subsea flanges, chemical plant process piping carrying corrosive fluids, coastal pipeline installations, seawater cooling system piping, and chlorine or acid service process lines where carbon steel stud bolts would suffer external atmospheric corrosion and thread seizing in the flange bolt holes. ASTM A1082 stainless steel full thread stud bolts are used with matching stainless steel heavy hex nuts per ASME B18.2.2 to form complete, fully corrosion-resistant flange bolting assemblies that maintain their integrity and disassembly capability throughout the full design service life of the piping system. EN 10204 Type 3.1 material certification covering chemical analysis, mechanical testing, and heat treatment is supplied with every ASTM A1082 stud bolt lot for quality-assured project procurement.
| Nominal Size | Diameter, D | Chamfered Thread Distance, U | |||||
|---|---|---|---|---|---|---|---|
| UNC Threads | UNF Threads | 8UN Threads | |||||
| Min. | Max. | Min. | Max. | Min. | Max. | ||
| 1/4 | 6.350 | 1.270 | 2.540 | 0.914 | 1.803 | … | … |
| 5/16 | 7.938 | 1.422 | 2.819 | 1.067 | 2.108 | … | … |
| 3/8 | 9.525 | 1.600 | 3.175 | 1.067 | 2.108 | … | … |
| 7/16 | 11.113 | 1.829 | 3.632 | 1.270 | 2.540 | … | … |
| 1/2 | 12.700 | 1.956 | 3.912 | 1.270 | 2.540 | … | … |
| 9/16 | 14.288 | 2.134 | 4.242 | 1.422 | 2.819 | … | … |
| 5/8 | 15.875 | 2.311 | 4.623 | 1.422 | 2.819 | … | … |
| 3/4 | 19.050 | 2.540 | 5.080 | 1.600 | 3.175 | … | … |
| 7/8 | 22.225 | 2.819 | 5.639 | 1.829 | 3.632 | … | … |
| 1 | 25.400 | 3.175 | 6.350 | 2.134 | 4.242 | … | … |
| 1 1/8 | 28.575 | 3.632 | 7.264 | 2.134 | 4.242 | 3.175 | 6.350 |
| 1 1/4 | 31.750 | 3.632 | 7.264 | 2.134 | 4.242 | 3.175 | 6.350 |
| 1 3/8 | 34.925 | 4.242 | 8.458 | 2.134 | 4.242 | 3.175 | 6.350 |
| 1 1/2 | 38.100 | 4.242 | 8.458 | 2.134 | 4.242 | 3.175 | 6.350 |
| 1 5/8 | 41.275 | … | … | … | … | 3.175 | 6.350 |
| 1 3/4 | 44.450 | 5.080 | 10.160 | … | … | 3.175 | 6.350 |
| 1 7/8 | 47.625 | … | … | … | … | 3.175 | 6.350 |
| 2 | 50.800 | 5.639 | 11.278 | … | … | 3.175 | 6.350 |
| 2 1/4 | 57.150 | 5.639 | 11.278 | … | … | 3.175 | 6.350 |
| 2 1/2 | 63.500 | 6.350 | 12.700 | … | … | 3.175 | 6.350 |
| 2 3/4 | 69.850 | 6.350 | 12.700 | … | … | 3.175 | 6.350 |
| 3 | 76.200 | 6.350 | 12.700 | … | … | 3.175 | 6.350 |
| 3 1/4 | 82.550 | 6.350 | 12.700 | … | … | 3.175 | 6.350 |
| 3 1/2 | 88.900 | 6.350 | 12.700 | … | … | 3.175 | 6.350 |
| 3 3/4 | 95.250 | 6.350 | 12.700 | … | … | 3.175 | 6.350 |
| 4 | 101.600 | 6.350 | 12.700 | … | … | 3.175 | 6.350 |
| 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 |
| Nominal Size | Diameter, D | Chamfered Thread Distance, U | |||||
|---|---|---|---|---|---|---|---|
| UNC Threads | UNF Threads | 8UN Threads | |||||
| Min. | Max. | Min. | Max. | Min. | Max. | ||
| 1/4 | 0.2500 | 0.050 | 0.100 | 0.036 | 0.071 | … | … |
| 5/16 | 0.3125 | 0.056 | 0.111 | 0.042 | 0.083 | … | … |
| 3/8 | 0.3750 | 0.063 | 0.125 | 0.042 | 0.083 | … | … |
| 7/16 | 0.4375 | 0.072 | 0.143 | 0.050 | 0.100 | … | … |
| 1/2 | 0.5000 | 0.077 | 0.154 | 0.050 | 0.100 | … | … |
| 9/16 | 0.5625 | 0.084 | 0.167 | 0.056 | 0.111 | … | … |
| 5/8 | 0.6250 | 0.091 | 0.182 | 0.056 | 0.111 | … | … |
| 3/4 | 0.7500 | 0.100 | 0.200 | 0.063 | 0.125 | … | … |
| 7/8 | 0.8750 | 0.111 | 0.222 | 0.072 | 0.143 | … | … |
| 1 | 1.0000 | 0.125 | 0.250 | 0.084 | 0.167 | … | … |
| 1 1/8 | 1.1250 | 0.143 | 0.286 | 0.084 | 0.167 | 0.125 | 0.250 |
| 1 1/4 | 1.2500 | 0.143 | 0.286 | 0.084 | 0.167 | 0.125 | 0.250 |
| 1 3/8 | 1.3750 | 0.167 | 0.333 | 0.084 | 0.167 | 0.125 | 0.250 |
| 1 1/2 | 1.5000 | 0.167 | 0.333 | 0.084 | 0.167 | 0.125 | 0.250 |
| 1 5/8 | 1.6250 | … | … | … | … | 0.125 | 0.250 |
| 1 3/4 | 1.7500 | 0.200 | 0.400 | … | … | 0.125 | 0.250 |
| 1 7/8 | 1.8750 | … | … | … | … | 0.125 | 0.250 |
| 2 | 2.0000 | 0.222 | 0.444 | … | … | 0.125 | 0.250 |
| 2 1/4 | 2.2500 | 0.222 | 0.444 | … | … | 0.125 | 0.250 |
| 2 1/2 | 2.5000 | 0.250 | 0.500 | … | … | 0.125 | 0.250 |
| 2 3/4 | 2.7500 | 0.250 | 0.500 | … | … | 0.125 | 0.250 |
| 3 | 3.0000 | 0.250 | 0.500 | … | … | 0.125 | 0.250 |
| 3 1/4 | 3.2500 | 0.250 | 0.500 | … | … | 0.125 | 0.250 |
| 3 1/2 | 3.5000 | 0.250 | 0.500 | … | … | 0.125 | 0.250 |
| 3 3/4 | 3.7500 | 0.250 | 0.500 | … | … | 0.125 | 0.250 |
| 4 | 4.0000 | 0.250 | 0.500 | … | … | 0.125 | 0.250 |
| Range, LT | Tolerances |
|---|---|
| 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 |
ASTM A1082/A1082M (2016) Table 1 lists 14 duplex (ferritic-austenitic) grades, S31100, S31260, S31803, S32101, S32202, S32205 (2205), S32304 (2304), S32506, S32550 (255), S32750 (2507), S32760, S32906, S32950 and S39277, and 5 precipitation-hardening grades, S15700 (Type 632), S17400 (Type 630), S17600 (Type 635), S17700 (Type 631) and S35500 (Type 634). Grade selection depends on design, service conditions and the mechanical properties required.
Dimensions follow ASME B16.5, tabulated on this page. ASTM A1082/A1082M sets chemistry (Table 1), heat treatment and mechanical properties (Tables 2 to 4) and marking (Table 5). ASTM A962/A962M general requirements also apply, and A1082 prevails where the two conflict (clause 4.1). Inch-pound units apply unless the order specifies A1082M (clause 1.4).
ISO 15156-3 Table A.24 accepts wrought duplex stainless steel for any equipment when it is solution-annealed and liquid-quenched or rapidly cooled, has 35 % to 65 % ferrite and has had no ageing heat treatment. With 30 ≤ PREN ≤ 40 and Mo ≥ 1.5 % the limit is 232 °C (450 °F) and 10 kPa (1.5 psi) H2S partial pressure; with 40 < PREN ≤ 45 it is 232 °C (450 °F) and 20 kPa (3 psi). Table A.27 accepts wrought 17-4 PH (S17400) at 33 HRC max after a double age at 620 °C (1150 °F) or a modified double age, for named wellhead, valve and subsurface components, up to 3.4 kPa (0.5 psi) H2S and pH 4.5 or above.
The grade symbol comes from Table 5 (clause 11.1), for example 32750 for S32750 or 174H for S17400 in H1150D. With Supplementary Requirement S2 the marking goes on one end of each stud; if the area is too small, the grade symbol may go on one end and the manufacturer's identification on the other. Studs under 3/8 in. [10 mm], and 1/4 in. [6 mm] studs that need more than three symbols, are marked by agreement.
Table 4: solution annealed at 1880 to 2060 °F [1025 to 1125 °C], water quenched. Up to and including 2 in.: tensile 116 ksi [800 MPa] and yield 80 ksi [550 MPa] min. Over 2 in.: 110 ksi [760 MPa] and 75 ksi [515 MPa] min. Elongation 15 % min and hardness 33 HRC or 310 HB max for both. The marking grade symbol is 32750 (Table 5).
