ASTM A193 Grade B8A is a standard material specification for corrosion resistant 304 stainless steel fasteners, for use in high tensile, high temperature and special purpose applications such as pressure piping & pressure vessels bolting. Grade B8A is similar to Grade B8 except the latter is carbide solution treated after head forming and the former is carbide solution treated in finished condition. Grade B8A is classified under class 1A tensile class and has a lower hardness requirement as compared to grade B8. This specification covers requirements for chemical composition, mechanical properties, hardness, heat-treatment and recommended nuts-washers for Grade B8A Fasteners.
| Element | Austenitic Stainless Steel |
|---|---|
| AISI 304 / 304L | |
| CompositionA, % | |
| Carbon | 0.08 max |
| Manganese | 2.00 |
| Phosphorus | 0.045 max |
| Sulfur | 0.030 max |
| Silicon | 1.00 max |
| Chromium | 18.00 - 20.00 |
| Nickel | 8.00 - 11.00 |
AThe intentional addition of Bi, Se, Te, and Pb is not permitted.
| Tensile Class | Tensile Strength, min, ksi |
Yield Strength, min, 0.2% offset, ksi |
Elongation in 4D, min, % |
Reduction of Area, min, % |
Hardness, max |
|
|---|---|---|---|---|---|---|
| Class 1A | 75 | 30 | 30 | 50 | 192 HBW or 90 HRB | |
Heat Treatment: Carbide Solution Treated in finished condition.
| Nut Specification | Washer Specification |
|---|---|
| ASTM A194 Grade 8A | ASTM A240 TP304 |
| Commonly Produced B8A 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 |