smo-254Alloys 254 / 254 SMO / 6 Mo is an austenitic stainless steel with a high molybdenum content. Coupled with Nickel and Copper this gives the alloy a good resistance to pitting and crevice corrosion, especially in environments containing halide ions, e.g. chloride, bromide and fluoride solutions.

254 SMO (UNS S31254) may offer a cost effective solution to Nickel and Titanium alloys in these environments.

Chemical Specification of Alloy 254

Elements C Cr Fe Mo Mn N Ni Nb P S Si V
Minimum 20.5 REMAINDER 1.5 4.0 0.2 11.5 0.1 0.1
Maximum 0.06 23.5 3.0 6.0 0.4 13.5 0.3 0.45 0.3 1.0 0.3


Basic Properties of Alloy 254- Mechanical Properties

0.2% Proof Stress (N/mm2 )[ksi] minimum 300 [43.5]
Ultimate Tensile Strength (N/mm2) [ksi] minimum 650[94.2]
Elongation (%) minimum 35
Hardness (HBN) 270 max
Reduction of Area(%) minimum 50


View Physical Properties of ALLOY ALLOY254 Physical Properties of Alloy 254

Density (Kg.m-3) 8000
Magnetic Permeability <1.05
Young’s Modulus (N/mm2) 200 x 103
Specific Heat 20°C (J.Kg-1.°K-1) 500
Electrical resistance, 20°C (µ.O.m) 0.85
Thermal conductivity, 20°C (W.m-1.°K-1) 13.5


Applications of Alloy 254

Chemical Process Industry: Urea Production, Organic and Fatty Acids, High halide concentrations
Marine Industry and Shipbuilding: Piping, Pumps, Valves, Heat exchangers
Oil and Gas Industry: Heat exchangers, Piping, Valves, Pumps
Pulp and Paper Industry: Bleach plant, vats, drums, press rolls, piping
Power Industry: Flue gas scrubbers
Desalination plant: Piping, Condensers

Alloy 254 Features

  • High strength compared to 316L and 317L austenitic stainless steels
  • Excellent ductility and impact strength at both ambient and sub-zero temperatures
  • Non-magnetic
  • Higher resistance to abrasion, erosion and cavitation erosion than 316 and 317 stainless
  • Listed in MR-01-75 for sour service oilfield applications

KEY Features of Alloy 254

  • Resistant to crevice corrosion in seawater
  • Excellent corrosion resistance in seawater and concentrated halide environments
  • High resistance to stress corrosion cracking
  • Good resistance to erosion corrosion
  • Excellent ductility and impact strength at both ambient and sub-zero temperatures
  • Low magnetic permeability