A320 B8M Stud Bolt
A320 B8M Stud Bolt
Manufacturers:
ASTM A320 Grade B8M studs are manufactured from AISI 316 stainless steel, and tested to meet A320. Dimensional specifications are governed by ASME B18.31.2. Grade markings consists of both the grade symbol "B8M" and the manufacturer's identification mark on one end of each stud 3/8" diameter and larger. Manufacturer's marking may be placed on other end if insufficient space. A320 grade B8 all thread studs having diameters above 1" are most common 8UN (8 threads per inch). For use in pressure vessels, valves, flanges, and fittings for low temperature service. A193 grade B8M studs available for high temperature or high pressure service.
Products
Mechanical Properties
| AISI 316 Stainless Steel, Carbide Solution Treated | Per ASTM A320/A320M-15a | ||||
| Material | Tensile Strength |
Yield Strength, 0.2% offset |
Elongation in 2 in. or 50 mm |
Reduction of Area |
Hardness |
| Min ksi | Min ksi | Min % | Min % | Max | |
| 316 Stainless Steel | 75 | 30 | 30 | 50 | 223 HBW or 96 HRB (1) |
- 1. For sizes 3⁄4 in. [20 mm] in diameter and smaller, a maximum hardness of 241 HBW (100 HRB) is permitted.
Governing Standards
| ASTM A320 | Covers alloy steel bolting materials and bolting components for pressure vessels, valves, flanges, and fittings for low-temperature service. |
| ASME B18.31.2 | Covers the complete dimensional and general data for continuous thread, flange studs (stud bolts), and double-end inch-dimensioned studs. |
| ASME B1.1 UNC & UNF Class 2A | Specifies the thread form, series, class, allowance, tolerance, and designation for unified screw threads. |
Grade B8M Stainless Steel Material Marking
Stud Flange Charts
| FLANGE | NOMINAL PIPE DIAMETER | ||||||||||
| CLASS | BOLTING | 1/2 | 3/4 | 1 | 1-1/4 | 1-1/2 | 2 | 2-1/2 | 3 | 3-1/2 | 4 |
| 150# | Number | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 8 | 8 |
| Diameter | 1/2 | 1/2 | 1/2 | 1/2 | 1/2 | 5/8 | 5/8 | 5/8 | 5/8 | 5/8 | |
| Stud Bolt Length | 2-1/4 | 2-1/2 | 2-1/2 | 2-3/4 | 2-3/4 | 3-1/4 | 3-1/2 | 3-1/2 | 3-1/2 | 3-1/2 | |
| Mach Bolt Length | 2 | 2 | 2-1/4 | 2-1/4 | 2-1/2 | 2-3/4 | 3 | 3 | 3 | 3 | |
| 300# | Number | 4 | 4 | 4 | 4 | 4 | 8 | 8 | 8 | 8 | 8 |
| Diameter | 1/2 | 5/8 | 5/8 | 5/8 | 3/4 | 5/8 | 3/4 | 3/4 | 3/4 | 3/4 | |
| Stud Bolt Length | 2-1/2 | 3 | 3 | 3-1/4 | 3-1/2 | 3-1/2 | 4 | 4-1/4 | 4-1/4 | 4-1/2 | |
| Mach Bolt Length | 2-1/4 | 2-1/2 | 2-1/2 | 2-3/4 | 3 | 3 | 3-1/4 | 3-1/2 | 3-3/4 | 3-3/4 | |
| 600# | Number | 4 | 4 | 4 | 4 | 4 | 8 | 8 | 8 | 8 | 8 |
| Diameter | 1/2 | 5/8 | 5/8 | 5/8 | 3/4 | 5/8 | 3/4 | 3/4 | 7/8 | 7/8 | |
| Stud Bolt Length | 3 | 3-1/2 | 3-1/2 | 3-3/4 | 4-1/4 | 4-1/4 | 4-3/4 | 5 | 5-1/2 | 5-3/4 | |
| 900# | Number | 4 | 4 | 4 | 4 | 4 | 8 | 8 | 8 | - | 8 |
| Diameter | 3/4 | 3/4 | 7/8 | 7/8 | 1 | 7/8 | 1 | 7/8 | - | 1-1/8 | |
| Stud Bolt Length | 4-1/4 | 4-1/2 | 5 | 5 | 5-1/2 | 5-3/4 | 6-1/4 | 5-3/4 | - | 6-3/4 | |
| 1500# | Number | 4 | 4 | 4 | 4 | 4 | 8 | 8 | 8 | - | 8 |
| Diameter | 3/4 | 3/4 | 7/8 | 7/8 | 1 | 7/8 | 1 | 1-1/8 | - | 1-1/4 | |
| Stud Bolt Length | 4-1/4 | 4-1/2 | 5 | 5 | 5-1/2 | 5-3/4 | 6-1/4 | 7 | - | 7-3/4 | |
| 2500# | Number | 4 | 4 | 4 | 4 | 4 | 8 | 8 | 8 | - | 8 |
| Diameter | 3/4 | 3/4 | 7/8 | 1 | 1-1/8 | 1 | 1-1/8 | 1-1/4 | - | 1-1/2 | |
| Stud Bolt Length | 4-3/4 | 5 | 5-1/2 | 6 | 6-3/4 | 7 | 7-3/4 | 8-3/4 | - | 10 | |
| FLANGE | NOMINAL PIPE DIAMETER | ||||||||||
| CLASS | BOLTING | 5 | 6 | 8 | 10 | 12 | 14 | 16 | 18 | 20 | 24 |
| 150# | Number | 8 | 8 | 8 | 12 | 12 | 12 | 16 | 16 | 20 | 20 |
| Diameter | 3/4 | 3/4 | 3/4 | 7/8 | 7/8 | 1 | 1 | 1-1/8 | 1-1/8 | 1-1/4 | |
| Stud Bolt Length | 3-3/4 | 4 | 4-1/4 | 4-1/2 | 4-3/4 | 5-1/4 | 5-1/4 | 5-3/4 | 6-1/4 | 6-3/4 | |
| Mach Bolt Length | 3-1/4 | 3-1/4 | 3-1/2 | 4 | 4 | 4-1/2 | 4-1/2 | 5 | 5-1/2 | 6 | |
| 300# | Number | 8 | 12 | 12 | 16 | 16 | 20 | 20 | 24 | 24 | 24 |
| Diameter | 3/4 | 3/4 | 7/8 | 1 | 1-1/8 | 1-1/8 | 1-1/4 | 1-1/4 | 1-1/4 | 1-1/2 | |
| Stud Bolt Length | 4-3/4 | 4-3/4 | 5-1/2 | 6-1/4 | 6-3/4 | 7 | 7-1/2 | 7-3/4 | 8 | 9 | |
| Mach Bolt Length | 4-1/4 | 4-1/4 | 4-3/4 | 5-1/2 | 5-3/4 | 6-1/4 | 6-1/2 | 6-3/4 | 7-1/4 | 8 | |
| 600# | Number | 8 | 12 | 12 | 16 | 20 | 20 | 20 | 20 | 24 | 24 |
| Diameter | 1 | 1 | 1-1/8 | 1-1/4 | 1-1/4 | 1-3/8 | 1-1/2 | 1-5/8 | 1-5/8 | 1-7/8 | |
| Stud Bolt Length | 6-1/2 | 6-3/4 | 7-1/2 | 8-1/2 | 8-3/4 | 9-1/4 | 10 | 10-3/4 | 11-1/4 | 13 | |
| 900# | Number | 8 | 12 | 12 | 16 | 20 | 20 | 20 | 20 | 20 | 20 |
| Diameter | 1-1/4 | 1-1/8 | 1-3/8 | 1-3/8 | 1-3/8 | 1-1/2 | 1-5/8 | 1-7/8 | 2 | 2-1/2 | |
| Stud Bolt Length | 7-1/2 | 7-1/2 | 8-3/4 | 9-1/4 | 10 | 10-3/4 | 11-1/4 | 12-3/4 | 13-3/4 | 17-1/4 | |
| 1500# | Number | 8 | 12 | 12 | 12 | 16 | 16 | 16 | 16 | 16 | 16 |
| Diameter | 1-1/2 | 1-3/8 | 1-5/8 | 1-7/8 | 2 | 2-1/4 | 2-1/2 | 2-3/4 | 3 | 3-1/2 | |
| Stud Bolt Length | 9-3/4 | 10-1/4 | 11-1/2 | 13-1/4 | 14-3/4 | 16 | 17-1/2 | 19-1/2 | 21-1/4 | 24-1/4 | |
| 2500# | Number | 8 | 8 | 12 | 12 | 12 | - | - | - | - | - |
| Diameter | 1-3/4 | 2 | 2 | 2-1/2 | 2-3/4 | - | - | - | - | - | |
| Stud Bolt Length | 11-3/4 | 13-1/2 | 15 | 19-1/4 | 21-1/4 | - | - | - | - | - | |
- All dimensions are in inches.
Chemical Properties
| Per ASTM A320/A320M-15a | |||||||||
| Grade | Material | Carbon | Manganese | Phosphorus | Sulfur | Silicon | Nickel | Chromium | Molybdenum |
| % by weight | % by weight | % by weight | % by weight | % by weight | % by weight | % by weight | % by weight | ||
| B8M | 316 Stainless Steel | 0.08 max | 2.00 max | 0.045 max | 0.030 max | 1.00 max | 10.0-14.0 | 16.0-18.0 | 2.00-3.00 |