ASTM A193 /A320 Gr B8.B8m Class 1&2

Our company, RatnaExports.com, manufactures screws, nuts, and stud bolts in stainless steel A193 B8M and A320 B8M, NI-Cr austenitic stainless steel. They are hardened through cooling and warping, providing better corrosion resistance than type 304 concerning pitting caused by chloride ions.

A193 B8M and A320 B8M are two materials commonly used as components in equipment used in the chemical, pharmaceutical, photographic, food, textile, and paper industries, as well as parts of furnaces, heat exchangers, and orthopedics.

In terms of corrosion resistance, steel is excellent in the atmosphere and has a large variety of salts, organic acids, and food substances; it is pretty good regarding poor solutions of reducing acids, and it has an improved corrosion resistance compared to other austenitic steels without Mo, halides, and seawater.

Because type 316 has a relatively low carbon content, it is slightly susceptible to intercrystalline corrosion. In any case, it is recommended to avoid slow heating and cooling between 450°C and 900°C.

During current “on-order” conditions, the heat oxidation resistance of A193 B8M and A320 B8M is up to 850°C, and in fitful “on-order” conditions, it can withstand up to 800°C. It can be welded without any particular problems. When electrodes are required, you must use electrodes made from the same type of steel.

The ASTM A193 Grade B8M is a standard material specification for high-strength 316/316L stainless steel bolts, screws, studs, or other external threaded fasteners for high-temperature, high-pressure service, as well as other special applications.

There are two types of tensile classes that A193 Grade B8M is classified into, namely class 1 and class 2, although, in terms of chemical composition, it is equivalent to AISI 316/316L stainless steel with improved strength.

High-strength pipeline bolts are used. A193 Grade B8M class 1 bolts are carbide solution treated with a maximum tensile strength requirement of 75 ksi or 515 MPa, yield 30 ksi or 205 MPa, and maximum hardness of 223 HBW. The B8M class 2 bolts are carbide solution treated, and strain hardened to achieve higher tensile strength requirements of 110 ksi or 760 MPa, 95 ksi or 655 MPa, and maximum hardness of 321 HBW or 35HRC.

For high-temperature, high-pressure service, and other special-purpose applications, ASTM A193 Grade B8M is the standard material specification for high tensile 316/316L stainless steel bolts, screws, studs, or other externally threaded fasteners that are intended for use in high-temperature, high-pressure environments.

For corrosion-resistant 316 stainless steel fasteners, such as bolts, screws, studs, threaded rods, and other externally threaded parts such as pressure piping and pressure vessels bolting ASTM A193 Grade B8M Class 1 is a standard material specification. The bolts are used in high tensile, high temperature, and special purpose applications such as pressure piping and pressure vessel bolting. 

There are three grades of B8M stainless steel: 316 stainless steel with a minimum tensile strength of 75 ksi, a yield strength of 30 ksi, and a maximum hardness requirement of 223 HBW or 96 HRB. For Grade B8M Class 1 Fasteners, this specification outlines the requirements for chemical composition, mechanical properties, hardness, heat treatment, and recommended nuts-washers.