ASTM A193 Grade B8MNA is a standard material specification for high strength 316N 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 B8MNA is a carbide solution treated 316N stainless steel classified under tensile class 1A and having minimum tensile requirement of 75 ksi, yield 30 ksi and maximum hardness limit of 192 HBW or 90 HRB. This specification covers requirements for chemical composition, mechanical properties, hardness, heat-treatment and recommended nuts-washers for Grade B8MNA Fasteners.
| Element | Nitrogen Enhanced Stainless Steel |
|---|---|
| AISI 316N / UNS S31651 | |
| 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 - 13.00 |
| Molybdenum | 2.00 - 3.00 |
| Nitrogen | 0.10 - 0.16 |
AThe intentional addition of Bi, Se, Te, and Pb is not permitted.
| Tensile Class | Diameter, Inch | Tensile Strength, min, ksi |
Yield Strength, min, 0.2% offset, ksi |
Elongation in 4D, min, % |
Reduction of Area, min, % |
Hardness, max |
|
|---|---|---|---|---|---|---|---|
| Class 1A | All Sizes | 80 | 35 | 30 | 40 | 223 HBW or 96 HRBB | |
Heat Treatment: Carbide Solution Treated in finished condition.
| Nut Specification | Washer Specification |
|---|---|
| ASTM A194 Grade 8MNA | ASTM A240 UNS S31651 |
| Commonly Produced B8MNA 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 |