ASTM A193 Grade B8 Class 2 Specification

ASTM A193 Grade B8 Class 2 Specification for high tensile bolts, screws, stud bolts, anchor bolts, threaded rods and other externally threaded fasteners, made from 304 stainless steel. ASTM A193 Grade B8 Class 2 is a standard material specification for corrosion resistant austenitic stainless steel fasteners, for use in high tensile, high temperature and special purpose applications such as pressure piping & pressure vessels bolting. Grade B8 Class 2 is a carbide-solution-treated & strain-hardened 304 stainless steel with minimum tensile requirement of 125 ksi, yield 100 ksi and maximum hardness of 35 HRC. This specification covers requirements for chemical composition, mechanical properties, hardness, heat-treatment and recommended nuts-washers for Grade B8 Class 2 Fasteners.

Chemical Composition

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.

Mechanical Properties

Tensile Class	Diameter, Inch	Tensile Strength, min, ksi	Yield Strength, min, 0.2% offset, ksi	Elongation in 4D, min, %	Reduction of Area, min, %	Hardness, max
							Class 2B,C	3/4 and under	125	100	12	35	321 HBW or 35 HRC
								over 3/4 to 1 inclusive	115	80	15	35
over 1 to 1-1/4 inclusive	105	65	20	35
over 1-1/4 to 1-1/2 inclusive	100	50	28	50

B: Carbide Solution Treated and Strain Hardened
C: For diameters 11⁄2 and over, center (core) properties may be lower than indicated by test reports which are based on values determined at 1⁄2 radius.

Recommended Nuts & Washers

Nut Specification	Washer Specification
ASTM A194 Grade 8	ASTM A240 TP304

Fasteners

Commonly Produced B8 Class 2 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