ASTM-A193 Mechanical Properties

ASTM-A193 Mechanical Properties / A193M

This specification covers ASTM-A193 Mechanical Properties for inch and metric size alloy and stainless steel bolting material for pressure vessels, valves, flanges, and fittings for high temperature service.  The term bolting used in this specification includes bars, bolts, hex bolts, hex head cap screws, screws, studs, stud bolts, and wires.  Although A193 fastener grades are available in UNC (unified national course) and UNF (unified fine) thread pitch, it is common to find sizes 1″ and larger in “8 thread” (8 TPI – threads per inch).




Grade and ClassDiameterTensile Strength Min KSIYield Strength 0.2% Offset KSIElongation in 4D, Min, %Reduction of Area Min, %Hardness Max BrinellHardness Max Rockwell
B5up to 4″ incl100801650
B6up to 4″ incl110851550
B6Xup to 4″ incl90701650C26
B7to 2-1/2″1251051650C35
over 2-1/2 to 4″115951650C35
over 4″ to 7″100751850C35
B7Mup to 4″ incl100801850235B99
over 4″ to 7″100751850235B99
B16to 2-1/2″1251051850321C35
over 2-1/2″ to 4″110951745321C35
over 4″ to 7″100851645321C35
Classes 1 and 1D: B8, B8M, B8P, B8LN, B8MLALL75303050223B96
Class 1: B8C, B8TALL75303050223B96
Class 1A: B8A, B8CA, B8MA, B8PA, B8TA, B8LNA, B8MLNA, B8NA, B8MNA, B8MLCuNAALL75303050192B90
Classes 1B & 1D: B8N, B8MN, B8MLCuNALL80353040223B96
Class 1C and 1D: B8RALL100553555271C28
Class 1C: B8RAALL100553555271C28
Classes 1C and 1D: B8SALL95503555271C28
Classes 1C: B8SAALL95503555271C28
Class 2: B8, B8C, B8P, B8T, B8Nto 3/4″1251001235321C35
over 3/4″ to 1″115801535321C35
over 1″ to 1-1/4″105652045321C35
over 1-1/4 to 1-1/2″ incl100502845321C35
Class 2 B8M, B8MN, B8MLCuNto 3/4″110961545321C35
over 3/4″ to 1″100802045321C35
over 1″ to 1-1/4″95652545321C35
over 1-1/4 to 1-1/2″ incl90503045321C35
Class 2B: B8, B8M2to 2″ incl95752540321C35
over 2″ to 2-1/2″ incl90653040321C35
over 2-1/2 ” to 3″ incl80553040321C35
Class 2C: B8M3to 2″ incl85653060321C35


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