ASTM A193 Grade B8N Class 1B Specification

ASTM A193 Grade B8N Class 1B 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 1B 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 1B is a carbide solution treated 304N stainless steel having minimum tensile requirement of 80 ksi, yield 30 ksi and maximum hardness limit of 223 HBW or 96 HRB. This specification covers requirements for chemical composition, mechanical properties, hardness, heat-treatment and recommended nuts-washers for Grade B8N Class 1B 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,
maxA
Class 1B All Sizes 80 35 30 40 223 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.

Recommended Nuts & Washers

Nut Specification Washer Specification
ASTM A194 Grade 8N ASTM A240 UNS S30451

Fasteners

Commonly Produced B8N Class 1B Fasteners
Hex Bolts Heavy Hex Bolts Stud Bolts Threaded Rods Anchor Bolts
Eye Bolts Socket Head Cap Screws Countersunk Screws U Bolts Square Head Bolts