ASTM A193 Grade B8MA Specification for high tensile bolts, screws, stud bolts, anchor bolts, threaded rods and other externally threaded fasteners, made from 316 stainless steel.

ASTM A193 Grade B8MA is a standard material specification for corrosion resistant 316 stainless steel fasteners such as bolts, screws, studs, 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 B8MA is a carbide solution treated 316 stainless steel and similar to Grade B8M except the latter is carbide solution treated after head forming and the former is a carbide solution treated in finished condition. Grade B8MA is classified under tensile class 1A having a minimum tensile requirement of 75 ksi, yield 30 ksi and maximum hardness limit of 190 HWB or 90 HRB. This specification covers requirements for chemical composition, mechanical properties, hardness, heat-treatment and recommended nuts-washers for Grade B8MA Fasteners.

Chemical Composition

Element	Austenitic Stainless Steel
	AISI 316 / 316L
	CompositionA, %
Carbon	0.08 max
Manganese	2.00
Phosphorus	0.045 max
Sulfur	0.030 max
Silicon	1.00 max
Chromium	16.00 - 18.00
Nickel	10.00 - 14.00
Molybdenum	2.00 - 3.00

^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 1A	All Sizes	75	30	30	50	192 HBW or 90 HRB

Heat Treatment: Carbide Solution Treated in finished condition.