ASTM A193 Grade B8CLN Class 1 Specification for high tensile bolts, screws, stud bolts, anchor bolts, threaded rods and other externally threaded fasteners, made from 347LN stainless steel.

ASTM A193 Grade B8CLN Class 1 is a standard material specification for nitrogen enhanced corrosion resistant grade 347LN stainless steel fasteners, for use in high tensile, high temperature and special purpose applications such as pressure piping & pressure vessels bolting. Grade B8CLN Class 1 is a carbide solution treated 347LN stainless steel having minimum tensile requirement of 75 ksi, yield 30 ksi and maximum hardness limit of 223 HBW or 96 HRB. ASTM A193 specification covers requirements for chemical composition, mechanical properties, hardness, heat-treatment and recommended nuts-washers for Grade B8CLN Class 1 Fasteners.

Chemical Composition

Element	Austenitic Stainless Steel
	AISI 347LN / UNS S34751
	CompositionA, %
Carbon	0.005 - 0.020
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	15 x Carbon Content min
Nitrogen	0.06 - 0.10

^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, maxA
							Class 1	All Sizes	75	30	30	50	223 HBW or 96 HRB

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