ASTM A193 Grade B8C Class 1 Specification for high tensile bolts, screws, stud bolts, anchor bolts, threaded rods and other fasteners, made from carbide solution treated 347 stainless steel.

ASTM A193 Grade B8C Class 1 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 1 is a carbide solution treated 347 stainless steel with minimum tensile requirement of 75 ksi, yield of 30 ksi & maximum hardness requirement of 223 HBW or 96 HRB. This specification covers requirements for chemical composition, mechanical properties, hardness, heat-treatment and recommended nuts-washers for Grade B8C Class 1 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 1	All Sizes	75	30	30	50	223 HBW or 96 HRBNote

Heat Treatment: Carbide Solution Treated
Note: For sizes 3⁄4 in. in diameter and smaller, a maximum hardness of 241 HBW (100 HRB) is permitted.