254 SMO (UNS S31254 / W.Nr. 1.4547)

254 SMO (UNS S31254 / W.Nr. 1.4547) is a super austenitic stainless steel that is well known for its outstanding resistance to pitting, crevice corrosion, stress cracking, and fatigue corrosion.

Equivalent Grades

254 SMO
S31254X1CrNiMoCuN20-18-71.4547Z1 CNDU 20.18.06AZX1CrNiMoCuN20-18-7

Chemical Composition, %

254 SMO≤0.02≤0.80≤1.0≤0.03≤0.0219.5-20.517.5-18.56.0-6.5Bal

Typical Physical and Mechanical Properties (RT, Annealed)

Density, g/cm3Melting Point, ℃Tensile Strength, MPaYield Strength, MPaELongation, %Hardness, HB

Available Products and Specifications

Rod, Bar, Wire and ForgingsASTM A479, ASTM B276
Plate, Sheet and StripASTM A240, ASTM B480
Pipe and TubeASTM A358, ASTM A312, ASTM A409, ASTM A813, ASTM A814, ASTM B690
Welding Product
OthersASTM B366


  • Excellent resistance to pitting and crevice corrosion, PRE = ≥42.5*
  • High resistance to general corrosion
  • High resistance to stress corrosion cracking
  • Higher strength than conventional austenitic stainless steels
  • Good weldability


254 SMO is used in the following applications:

  • Equipment for handling of seawater, such as seawater cooling, cooling water pipes, ballast water systems, firefighting systems etc.
  • Hydraulic and instrumentation tubing
  • Equipment in pulp bleaching plants
  • Components in gas cleaning systems
  • Tanks and pipelines for chemicals with high halide contents