Stainless Steel Grade 431

Technical Data Sheet

Alloy 431 is the most corrosion resistant of the martensitic grades. Due to Alloy 431's excellent tensile and torque strength and good toughness it is used in structural parts that are exposed to marine atmosphere, also for aircraft fasteners and fittings. 

Chemical Composition Limits
Weight% C P Si Ni Mn S Cr Fe Mo Cu N
Alloy 431
0.12-0.17 0.040 max 0.20-0.60 2-3 0.3 0.030 15.50-16.50 Bal 0.25 0.50 0.10

Typical Mechanical Properties


Material Condition
Tensile Strength (MPa) Proof Stress 0.2% (MPa) Elongation 2"% Reduction of Area Brinell Hardness
Alloy 431 Alloy 431 Annealed 862 655 20 55 260
Alloy 431 Alloy 431 Heat Treated AMS 5628 1379 1034 10 40 -

Grade 431 is available in Bar (Round), Strip, Wire, Rod, Billet. For all stock availability contact Sales.

Grade 431 Stainless Steel Bar, Wire, Forgings, Tube
AMS 5628 Bars / wire / forgings
ASTM A276 / ASME SA276
ASTM A478 / ASME A478
ASTM A314 / ASME SA314
ASTM A484 / ASME SA484
ASTM A580 / ASME SA580
BS 7S80
BS 970; 431S29
UNS S43100

For more information about Alloy 431 for use in medical applications, visit our medical division at

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Every effort is made to ensure that technical specifications are accurate. However, technical specifications included herein should be used as a guideline only. All specifications are subject to change without notice.