Carbide Solution Treated 304 Stainless Steel Continuous & Double-End Studs
ASTM A320 Grade B8 Class 1 are manufactured from carbide solution treated AISI 304 austenitic stainless steel, delivering exceptional corrosion resistance and full ductility for flanged pressure joints. As continuously threaded or double end studs per ASME B18.31.2, these Class 1 studs provide 75 ksi minimum tensile strength and 30 ksi yield strength with maximum hardness of 223 HBW or 96 HRB (241 HBW or 100 HRB permitted for sizes 3/4 in. [20 mm] and smaller). Class 1 Grade B8 is exempt from impact testing above -425°F [-255°C] (6.2.1.1), which makes B8 Class 1 suitable for low temperature pressure vessel, valve, flange, and fitting bolting where corrosion resistance matters more than strength.
| Grade Symbol | UNS Designation | C, max | Mn, max | P, max | S, max | Si, max | Ni | Cr | |
|---|---|---|---|---|---|---|---|---|---|
| ASTM A320 B8 | S30400(304) | Range,% | 0.08 | 2.00 | 0.045 | 0.030 | 1.00 | 8.0-11.0 | 18.0 - 20.0 |
| Grade and Class | Diameter, in. [mm] | Heat Treatment | Tensile Strength, min, ksi [MPa] | Yield Strength, min, ksi [MPa] (0.2 % offset) | Elongation in 2 in. or 50 mm, min, % | Reduction of Area, min, % | Hardness, max |
|---|---|---|---|---|---|---|---|
| ASTM A320 B8 Class 1 | All diameters | carbide solution treated | 75 [515] | 30 [205] | 30 | 50 | 223 HBWDor 96 HRB |
