ASTM A193 Grade B8C Class 2 Specification for high tensile bolts, screws, stud bolts, threaded rods and other fasteners, made from carbide solution treated & strain hardened 347 stainless steel.

ASTM A193 Grade B8C Class 2 is a standard material specification for corrosion resistant grade 347 stainless steel fasteners such as hex bolts, screws, stud bolts, anchor bolts, threaded rods and other externally threaded parts, for use in high tensile, high temperature and special purpose applications such as pressure piping & pressure vessels bolting. Grade B8C Class 2 is a carbide solution treated and strain hardened 347 stainless steel with minimum tensile requirement of 100 ksi, yield of 50 ksi & maximum hardness requirement of 321 HBW or 35 HRC. This specification covers requirements for chemical composition, mechanical properties, hardness, heat-treatment and recommended nuts-washers for Grade B8C Class 2 Fasteners.

Chemical Composition

Element	Austenitic Stainless Steel
	AISI 347
	CompositionA, %
Carbon	0.08 max
Manganese	2.00
Phosphorus	0.045 max
Sulfur	0.030 max
Silicon	1.00 max
Chromium	17.00 - 19.00
Nickel	9.00 - 12.00
Columbium + tantalum	10 x Carbon Content - 1.10

^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 2	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 11⁄2, inclusive	100	50	28	45

Heat Treatment: Carbide Solution Treated and Strain Hardened