ASTM A193 Grade B8MN 1D 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 B8MN Class 1D is a carbide solution treated 316N stainless steel further having a minimum tensile requirement of 80 ksi, yield 35 ksi and maximum hardness limit of 223 HBW or 96 HRB. This specification covers requirements for chemical composition, mechanical properties, hardness, heat-treatment and recommended nuts-washers for Grade B8MN Class 1D 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 1B & 1D | All Sizes | 80 | 35 | 30 | 40 | 223 HBW or 96 HRBA | |
Heat Treatment: Carbide Solution Treated
A: For sizes 3⁄4 in. in diameter and smaller, a maximum hardness of 241 HBW (100 HRB) is permitted.
| Nut Specification | Washer Specification |
|---|---|
| ASTM A194 Grade 8MN | ASTM A240 UNS S31651 |
| Commonly Produced B8MN Class 1D 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 |