ASTM A193 Grade B8N Class 2 Specification for high tensile bolts, screws, stud bolts, anchor bolts, threaded rods and other externally threaded fasteners, made from 304N stainless steel.

ASTM A193 Grade B8N Class 2 is a standard material specification for high strength 304N 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 B8N Class 2 is a carbide solution treated and strain hardened 304N stainless steel material having a minimum tensile requirement of 100 ksi, yield 50 ksi and maximum hardness limit of 321 HBW or 35 HRC. This specification covers requirements for chemical composition, mechanical properties, hardness, heat-treatment and recommended nuts-washers for Grade B8N Class 2 Fasteners.

Chemical Composition

Element	Austenitic Stainless Steel
	AISI 304N / UNS S30451
	CompositionA, %
Carbon	0.08 max
Manganese	2.00
Phosphorus	0.045 max
Sulfur	0.030 max
Silicon	1.00 max
Chromium	18.00 - 20.00
Nickel	8.00 - 11.00
Molybdenum	0.10 - 0.16

^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 2A	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 1-1/2 inclusive	100	50	28	45

Heat Treatment: Carbide Solution Treated & Strain Hardened.
A: For diameters 11⁄2 and over, center (core) properties may be lower than indicated by test reports which are based on values determined at 1⁄2 radius.