Serving the oil and gas Industry, we are a leading stockholder of ASTM A193 B8M grade bolts and fasteners.

Description of Material

ASTM A193 B8M is an austenitic stainless steel used throughout the Oil and Gas industry for general connections including valves, flanges, and fittings where corrosion protection is required. Provided as standard in a class 1 solution annealed condition for general use, this material is also available in a class 2 strain hardened condition to increase its strength and general mechanical properties.

LoneStar Fasteners Europe offer ASTM A193 B8M in commercial grades, covering the basic requirements of ASTM A193, but can also offer with supplementary testing meeting additional requirements of the standard or to meet the demands of OEM or international accredited certification bodies.

ASTM A193 B8M: Forms

  LoneStar Manufacture 
Stud Bolts
Hexagon Headed Bolting
Socket Headed Bolting
Double Ended and Waisted Studs
Associated OEM Parts

ASTM A193 B8M: Sizes and Threads 

  LoneStar Manufacture 
Metric Coarse
Metric Fine
Imperial UNC
Imperial 8UN
Imperial UNF
Metric sizes available Up to M100
Imperial sizes available Up to 6.00″

ASTM A193 B8M: Chemical Composition

Carbon 0.08 % Max
Manganese 2.00 % Max
Phosphorus 0.045 % Max
Sulphur 0.030 % Max
Silicon 1.00 % Max
Chromium 16.0-18.0 %
Nickel 10.0-14.0 %
Molybdenum 2.00-3.00 %

ASTM A193 B8M: Mechanical Properties

Class 1
Tensile Strength Min, Ksi 75
Yield Strength  min, 0.2% offset Ksi 30
Elongation in min% 30
Reduction of Area min% 50
Hardness Max 96 HRB


Class 2 ¾” and Under  ¾” to 1” Inc.
Tensile Strength Min, Ksi 110 100
Yield Strength  min, 0.2% offset Ksi 95 80
Elongation in min% 15 20
Reduction of Area min% 45 45
Hardness Max 35 HRC 35 HRC


Class 2 Over 1” to 1.1/4” Inc. Over 1.1/4” to 1.1/2” Inc.
Tensile Strength Min, Ksi 95 90
Yield Strength  min, 0.2% offset Ksi 65 50
Elongation in min% 25 30
Reduction of Area min% 45 45
Hardness Max 35 HRC 35 HRC

Similar or Equivalent Standards 

Class 1 Class 2
AISI 316 AISI 316
DIN X 5 Cr NiMo 18.1 DIN X5 Cr Ni Mo 18.10
B.S 1506.845 B.S 1506.845


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