All about A193 Grade B8 Fasteners

For use in high tensile, high temperature, and special purpose applications such as pressure piping and pressure vessel bolting, ASTM A193 Grade B8 is a standard material specification for austenitic stainless steel fasteners that resist corrosion. Class 1, Class 2, and Class 2B are subgroups of Grade B8, austenitic stainless steel that has been heat-treated and work-hardened (or both). Each subgroup has a distinct tensile strength. For Grade B8 Fasteners, the ASTM A193 specification outlines the necessary chemical composition, mechanical qualities, hardness, heat treatment, and suggested nuts-washers.

Chemically, A193 Grade B8 Fasteners are the same as (AISI 304) 18-8 stainless steel alloy. It has tensile strength that is divided into classes 1 and 2 depending on its tensile strength. A193 Grade B8 Class 1 bolts undergo carbide solution treatment to achieve a maximum tensile strength requirement of 75 ksi or 515 MPa, yield 30 ksi or 205 MPa, and maximum hardness of 223 HBW, whereas grade b8 class 2 bolts undergo carbide solution treatment and strain hardening to achieve a higher tensile requirement of 125 ksi or 860 MPa, 100 ksi or 690 MP For high strength pipeline bolting operations, grade B8 fasteners are employed.

The addition of molybdenum to SS ASTM A193 B8 Fasteners improves the corrosion resistance of the product. There is typically more nickel and a small amount of molybdenum in stainless steel ASME SA 193 B8 fasteners. Stainless Steel ASTM A193 B8 Nuts have essentially superior mechanical, physical, and manufacturing qualities as well as better corrosion resistance, especially against pitting corrosion in chloride conditions. In applications where corrosion resistance or strong raised temperature strength are required, stainless steel ASTM A193 B8 Bolts are frequently employed. For roll-formed structural components and cold-headed fasteners, stainless steel ASTM A193 B8 washers have high strength and low work-hardening rate grades.