F44 (UNS S31254 / W.Nr. 1.4547)

F44 (UNS S31254 / W.Nr. 1.4547) an austenitic stainless steel used in seawater and other aggressive chloride- bearing media. This grade has excellent resistance to pitting and crevice corrosion, high resistance to general corrosion and stress corrosion cracking, with a higher strength than conventional austenitic stainless steels, and good weldability.

Equivalent Grades

TrademarkGBGOSTASTMUNSDINW.Nr.NFBSJISSS
F44
254 SMO
F44S31254X1CrNiMoCuN20-18-71.4547Z1 CNDU 20.18.06AZX1CrNiMoCuN20-18-7

Chemical Composition, %

AlloyCSiMnPSCrNiMoNFe
254 SMO≤0.02≤0.80≤1.0≤0.03≤0.0219.5-20.517.5-18.56.0-6.50.18-0.25Bal

Typical Physical and Mechanical Properties (RT, Annealed)

Density, g/cm3Melting Point, ℃Tensile Strength, MPaYield Strength, MPaELongation, %Hardness, HRB
8.01130-1280655-850≥313≥35/

Available Products and Specifications

Rod, Bar, Wire and ForgingsASTM A182
Plate, Sheet and StripASTM A312
Pipe and TubeASTM A167, 240
Welding Product
OthersASTM A403

Features

The steel combines moderate mechanical strength (typically over 300 MPa yield strength) and high ductility with excellent corrosion resistance in seawater and a variety of industrial environments. Typically the alloy has a PREn (Pitting Resistance Equivalent) of 42-44 which ensures that the resistance to pitting corrosion is high. In addition, the steel provides good resistance to crevice corrosion. Ambient and sub-zero temperature notch ductility is very good. These attributes mean that this high molybdenum stainless steel can be used successfully as an alternative to 300 series austenitic stainless steels (such as type 316) in applications where higher mechanical strength and/or enhanced resistance to pitting and crevice corrosion is required.

Applications

Commercial applications for this engineering material include:

  • Pumps
  • Valves
  • Chokes
  • Pipework, flanges & manifolds
  • Oil & Gas industry components