ASTM A193 Grade B8MLCuN Class 1D is a standard material specification for corrosion resistant & high strength Alloy 254 / UNS S31254 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 B8MLCuN Class 1B and 1D is a carbide solution treated 6% moly stainless steel having a minimum tensile requirement of 80 ksi, yield 30 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 B8MLCuN Class 1B and 1D Fasteners.
| Element | Austenitic Stainless Steel |
|---|---|
| UNS S31254 / Alloy 254SMO / 1.4547 | |
| CompositionA, % | |
| Carbon | 0.02 max |
| Manganese | 1.00 |
| Phosphorus | 0.030 max |
| Sulfur | 0.010 max |
| Silicon | 0.80 max |
| Chromium | 19.50 - 20.50 |
| Nickel | 17.50 - 18.50 |
| Molybdenum | 6.00 - 6.50 |
| Nitrogen | 0.18 - 0.22 |
| Copper | 0.50 - 1.00 |
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 1D | All Sizes | 80 | 35 | 30 | 40 | 223 HBW or 96 HRB | |
Heat Treatment: Carbide Solution Treated.
| Nut Specification | Washer Specification |
|---|---|
| ASTM A194 Grade 8MLCuN | ASTM A240 UNS S31254 |
| Commonly Produced B8MLCuN 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 |