ASTM A193 Grade B8M Class 1 is a standard material specification for corrosion resistant 316 stainless steel fasteners such as bolts, screws, studs, threaded rods and other externally threaded parts, for use in high tensile, high temperature and special purpose applications such as pressure piping & pressure vessels bolting. Grade B8M Class is a carbide solution treated 316 stainless steel having a minimum tensile requirement of 75 ksi, yield 30 ksi and maximum hardness requirement of 223 HBW or 96 HRB. This specification covers requirements for chemical composition, mechanical properties, hardness, heat-treatment and recommended nuts-washers for Grade B8M Class 1 Fasteners.
| Element | Austenitic Stainless Steel |
|---|---|
| AISI 316 / 316L | |
| CompositionA, % | |
| Carbon | 0.08 max |
| Manganese | 2.00 |
| Phosphorus | 0.045 max |
| Sulfur | 0.030 max |
| Silicon | 1.00 max |
| Chromium | 16.00 - 18.00 |
| Nickel | 10.00 - 14.00 |
| Molybdenum | 2.00 - 3.00 |
AThe intentional addition of Bi, Se, Te, and Pb is not permitted.
| Tensile Class | Diameter, Inch min, ksi |
Tensile Strength, min, ksi |
Yield Strength, min, 0.2% offset, ksi |
Elongation in 4D, min, % |
Reduction of Area, min, % |
Hardness, max |
|
|---|---|---|---|---|---|---|---|
| Class 1 | All Sizes | 75 | 30 | 30 | 50 | 223 HBW or 96 HRB | |
Heat Treatment: Carbide Solution Treated.
| Nut Specification | Washer Specification |
|---|---|
| ASTM A194 Grade 8M | ASTM A240 TP316 |
| Commonly Produced B8M Class 1 Fasteners | ||||
|---|---|---|---|---|
| Hex Bolts | Heavy Hex Bolts | Stud Bolts | Threaded Rods | Anchor Bolts |
| Eye Bolts | Socket Head Cap Screws | Countersunk Screws | U Bolts | Square Head Bolts |