ASTM A193 Grade B8P Specification

ASTM A193 Grade B8P Specification for high tensile bolts, screws, stud bolts, anchor bolts, threaded rods and other externally threaded fasteners, made from 305 stainless steel.

ASTM A193 Grade B8P is a standard material specification for corrosion resistant austenitic stainless steel fasteners, for use in high tensile, high temperature and special purpose applications such as pressure piping & pressure vessels bolting. Grade B8P is a heat-treated, work-hardened (or both) austenitic stainless steel further divided into class 1, class 1D & class 2, each having a distinguished tensile strength. This specification covers requirements for chemical composition, mechanical properties, hardness, heat-treatment and recommended nuts-washers for Grade B8P Fasteners.

Tensile Class

Property Description
Class 1 Carbide Solution Treated
Class 1D Carbide Solution Treated
Class 2 Carbide Solution Treated & Strain Hardened

Chemical Composition

Element Austenitic Stainless Steel
AISI 305 / UNS S30500 / 1.4303
CompositionA, %
Carbon 0.12 max
Manganese 2.00
Phosphorus 0.045 max
Sulfur 0.030 max
Silicon 1.00 max
Chromium 17.00 - 19.00
Nickel 11.00 - 13.00

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 1 & 1DA All Sizes 75 30 30 50 223 HBW or 96 HRBB


Class 2C		 3/4 and under 125 100 12 35

321 HBW or 35 HRCD
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 50

A: Carbide Solution Treated
B: For sizes 3⁄4 in. in diameter and smaller, a maximum hardness of 241 HBW (100 HRB) is permitted.
C: Carbide Solution Treated and Strain Hardened
D: 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 8P ASTM A240 UNS S30500

Fasteners

Commonly Produced B8P 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