Grade B8M Class 2

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ASTM A193 Grade B8M Class 2 Specification for high tensile bolts, screws, stud bolts, anchor bolts, threaded rods and other externally threaded fasteners, made from 316 stainless steel. ASTM A193 Grade B8M Class 2 is a standard material specification for corrosion resistant 316 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 B8M Class 2 is strain hardened & carbide solution treated 316 stainless steel having minimum requirement of 100 ksi, yield 50 ksi with 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 B8M Class 2 Fasteners.


Chemical Composition

Element Austenitic Stainless Steel
AISI 316 / 316L
CompositionA, %
Carbon 0.08 max
Manganese 2.00
Phosphorus 0.045 max
Sulfur 0.030 max
Silicon 1.00 max
Chromium 16.00 - 18.00
Nickel 10.00 - 14.00
Molybdenum 2.00 - 3.00

AThe intentional addition of Bi, Se, Te, and Pb is not permitted.


Mechanical Properties

Tensile Class Diameter, Inch
min, ksi
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 110 95 15 45

321 HBW or 35 HRC
over 3/4 to 1 inclusive 100 80 20 45
over 1 to 1-1/4 inclusive 95 65 20 45
over 1-1/4 to 1-1/2 inclusive 90 50 30 45

Heat Treatment: Carbide Solution Treated and 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.


Recommended Nuts & Washers

Nut Specification Washer Specification
ASTM A194 Grade 8M ASTM A240 TP316

Fasteners

Commonly Produced B8M 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
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