ASTM A193 Grade B8MLCuNA Specification for high tensile bolts, screws, stud bolts, anchor bolts, threaded rods and other threaded fasteners, made from UNS S31254 / Alloy 254SMO stainless steel.

ASTM A193 Grade B8MLCuNA is a standard material specification for corrosion resistant & high strength Alloy 254 / UNS S31254 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 B8MLCuNA is a similar to Grade B8MLCuN except that the later is carbide solution treated after head forming and the former is carbide solution treated in finished condition. Grade B8MLCuNA is classified under tensile class 1A having minimum tensile requirement of 75 ksi, yield 30 ksi and maximum hardness limit of 192 HBW or 90 HRB. This specification covers requirements for chemical composition, mechanical properties, hardness, heat-treatment and recommended nuts-washers for Grade B8MLCuNA Fasteners.

Chemical Composition

Element	Austenitic Stainless Steel
	UNS S31254 / Alloy 254SMO / 1.4547
	CompositionA, %
Carbon	0.02 max
Manganese	1.00
Phosphorus	0.030 max
Sulfur	0.010 max
Silicon	0.80 max
Chromium	19.50 - 20.50
Nickel	17.50 - 18.50
Molybdenum	6.00 - 6.50
Nitrogen	0.18 - 0.22
Copper	0.50 - 1.00

^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.