ASTM A193 Grade B8T Class 1 is a standard material specification for corrosion resistant 321 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 B8T Class 1 is a carbide solution treated 321 stainless steel having minimum tensile requirement of 75 ksi, yield 30 ksi and maximum hardness limit of 223 HBW or 96 HRB. ASTM A193 specification covers requirements for chemical composition, mechanical properties, hardness, heat-treatment and recommended nuts-washers for Grade B8T Class 1 Fasteners.
| Element | Austenitic Stainless Steel |
|---|---|
| AISI 321 / 321H | |
| CompositionA, % | |
| Carbon | 0.08 max |
| Manganese | 2.00 |
| Phosphorus | 0.045 max |
| Sulfur | 0.030 max |
| Silicon | 1.00 max |
| Chromium | 17.00 - 19.00 |
| Nickel | 9.00 - 12.00 |
| Titanium | 5 x Carbon Content - 0.70 |
| Nitrogen | 0.10 max |
A: The 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 1 | All Sizes | 75 | 30 | 30 | 50 | 223 HBW or 96 HRB |
Heat Treatment: Carbide Solution Treated.
| Nut Specification | Washer Specification |
|---|---|
| ASTM A194 Grade 8T | ASTM A240 TP321 |
| Commonly Produced B8T 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 |