ASTM A193 Grade B8R Class 1D Specification

ASTM A193 Grade B8R Class 1D Specification for high tensile bolts, screws, stud bolts, threaded rods and other externally threaded fasteners, made from UNS S20910 / XM-19 / Nitronic 50 stainless steel.

ASTM A193 Grade B8R Class 1D is a standard material specification for high strengt, corrosion resistant UNS S20910 / XM-19 / Nitronic 50 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 B8R Class 1D is a carbide solution treated stainless steel material having minimum tensile requirement of 100 ksi, yield 55 ksi and maximum hardness limit of 271 HBW or 28 HRC. This specification covers requirements for chemical composition, mechanical properties, hardness, heat-treatment and recommended nuts-washers for Grade B8R Class 1D Fasteners.

Chemical Composition

Element Austenitic Stainless Steel
UNS S20910 / XM-19 / Nitronic 50
CompositionA, %
Carbon 0.06 max
Manganese 4.00 - 6.00
Phosphorus 0.045 max
Sulfur 0.030 max
Silicon 1.00 max
Chromium 20.50 - 23.50
Nickel 11.50 - 13.50
Molybdenum 1.50 - 3.00
Nitrogen 0.20 - 0.40
Columbium + tantalum 0.10 - 0.30
Vanadium 0.10 - 0.30

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 1D All Sizes 100 55 35 55 271 HBW or 28 HRC

Heat Treatment: Carbide Solution Treated

Recommended Nuts & Washers

Nut Specification Washer Specification
ASTM A194 Grade 8R ASTM A240 UNS S20910

Fasteners

Commonly Produced B8R Class 1D 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