ASTM A193 B8

ASTM A193 Standard Specification for Alloy-Steel and Stainless Steel Bolting Materials for High-Temperature Service

Grade: B8 — Austenitic Steels/S 30400 (304)

Chemical Requirements (Max. Composition, percent)

C: 0.08

Mn: 2.00

P: 0.035

S: 0.040

Si: 1.00

Cr: 18.0-20.0

Ni: 8.0-11.0


Mechanical Requirements —Metric Products

Class Diameter, [mm]

Tensile Strength,


Yield Strength,

min, 0.2 % offset, MPa


in 4D, min, %

Reduction of Area,

min, %



Classes 1 and 1D


223 HB or

96 HRB

Class 2, M20 and under

8606901235321 HB or 35 HRC
Class 2, over M20 to M24, incl7955501535

321 HB or 35 HRC

Class 2, over M24 to M30, incl

7254502035321 HB or 35 HRC
Class 2, over M30 to M36, incl6903452845

321 HB or 35 HRC

Class 2B, M48 and under

6555152540321 HB or 35 HRC
Class 2B, over M48 to M64, incl6204503040

321 HB or 35 HRC

Class 2B, over M64 to M72, incl5503803040

321 HB or 35 HRC

Heat-treated condition: normalized and tempered, or quenched and tempered, for the ferritic materials, and carbide solution treated (Class 1), carbide solution treated after finishing (Class 1A), and carbide solution treated and strain hardened(Classes 2, 2B and 2C), for the austenitic stainless steels; Classes 1B and 1C apply to the carbide solution-treated nitrogen-bearing stainless steels; Class 1D applies to material carbide solution treated by cooling rapidly from the rolling temperature.