ASTM A193 Grade B6X is a standard material specification for chromium-ferritic stainless steel fasteners, for use in high tensile, high temperature and special purpose applications such as pressure piping & pressure vessels bolting. Grade B6X is a heat-treated 12% chromium-ferritic magnetic 410 stainless steel with minimum tensile strength requirement of 110 ksi, yield 85 ksi. The difference between Grade B6 & B6X is lower tensile & yield requirement along with the maximum hardness requirement of 26 HRC in the latter. ASTM A193 specification covers requirements for chemical composition, mechanical properties, hardness, heat-treatment and recommended nuts-washers for Grade B6X Fasteners.
| Element | Ferritic Steel |
|---|---|
| Chromium Stainless Steel | |
| CompositionA, % | |
| Carbon | 0.08 - 0.15 |
| Manganese | 1.00 |
| Phosphorus | 0.040 max |
| Sulfur | 0.030 max |
| Silicon | 1.00 max |
| Chromium | 11.5 - 13.5 |
A: The intentional addition of Bi, Se, Te, and Pb is not permitted.
| Diameter, inch. | Tensile Strength, min, ksi |
Yield Strength, min, 0.2% offset, ksi |
Elongation in 4D, min, % |
Reduction of Area, min, % |
Hardness, max, HRC |
|---|---|---|---|---|---|
| up to 4, inclusive | 90 | 70 | 16 | 50 | 26 |
Heat Treatment: Quenched & Tempered at 1100ยบ F minimum.
| Nut Specification | Washer Specification |
|---|---|
| ASTM A194 Grade 6 | SS 410 |
| Commonly Produced B6X Fasteners | ||||
|---|---|---|---|---|
| Hex Bolts | Heavy Hex Bolts | Stud Bolts | Hex Screws | Anchor Bolts |
| Eye Bolts | Socket Head Cap Screws | Countersunk Screws | U Bolts | Square Head Bolts |