6% Moly Alloy Stainless Steel (UNS S31254)

AL6XN (UNS NO8367) or 254 SMO (UNS S31254) is high-alloy austenitic stainless steel designed for maximum resistance

6 moly ss uns n08926 suitable for high chloride environments such as seawater, pulp mill, bleach plants


6% Moly Alloy Stainless Steel (UNS S31254)
6% Moly Alloy Stainless Steel (UNS S31254)
6 moly ss uns n08926
6 moly ss uns n08926
AL6XN (UNS NO8367)AL6XN (UNS NO8367)

There are several names for UNS S31254, including 6 moly, 254SMO and NAS 185N. Belonging to the austenitic class of stainless steel, the 6 moly (s31254) is a highly corrosion resistant material. The chemistry of this particular austenitic stainless steel includes high contents of nickel, Chromium, as well as molybdenum. The alloy chemistry was designed in such a manner that the 6% moly stainless steel would demonstrate excellent corrosion resistance, irrespective of their exposure to severe corrosion environments, for instance, elevated temperature seawater.

Depending on the condition it is to be used for, the WNR 1.4547 is a stainless steel alloy that is attractive to several business owners because it not only offers an economical solution but also corrosion resistance properties that could rival that both Nickel alloys as well as pure titanium. The most important characteristic of the 254SMO (UNS S31254) is the fact that it provides excellent resistance Pitting Corrosion. This is a fact that can be attested by its high PREN value. The PREN value of 6 moly ss uns n08926 is higher than 42.5. For an alloy to be categorized as having excellent pitting resistance, the PREN value must be greater than 38. In addition to stronger mechanical properties, the AL6XN (UNS NO8367) derives its ability to resist crevice corrosion when in high Cl environments from its chemistry. As a high Nickel alloy containing steel, the 6 moly alloy also offers excellent resistance to stress corrosion cracking.


Chemical Composition Chart Of 6% Moly Alloy Stainless Steel (UNS S31254)




















Min. 40


Mechanical Characteristics of 6 moly ss uns n08926

Mechanical Properties
Condition: quenched



0.2% proof stress

Tensile strength

Elongation A5
% min.
L    Q     T

Impact strength
J min.
L    Q     T

St, Sch




25   – –    – –

70   – –    – –


≤ 75

– –   251)  – –

– –   55    – –

St = Bar , Sch = Forging,
Bl = Sheet or plate
L = Longitudinal, Q = Transverse, T = Tangential
1) < 3mm = A80mm specimen


benefits and characteristics

  • Very high melting point
  • Excellent thermal conductivity
  • Ability to bond with glass
  • Very high resistance to chloride stress corrosion cracking (CSCC)
  • Excellent electrical conductivity
  • High melting point
  • Its material yield strength is 50% greater than 300-series austenitic stainless steels
  • Excellent impact toughness
  • Highly resistant to chloride pitting, crevice and general corrosion
  • High density
  • Excellent weldability
  • Excellent workability



  • Seawater handling equipment such as heat exchangers and cooling water pipes
  • Flue gas desulphurization scrubbers
  • Paper and pulp Mill Bleach Systems; drums, vats and press rolls.
  • Flue gas desulphurisation units in power plants
  • Desalination Plants and equipment
  • Tall oil distillation columns and equipment
  • Oil and gas production equipment
  • Sea and Brackish Water pipelines
  • Chemical process plants
  • Tall oil distillation columns and equipment
  • Food processing equipment
  • Tanks and pipelines for various chemicals with high halide levels

6% Moly and Special Piping Materials

  • FITTINGS – ASTM / ASME / A403 / SA403 / UNS S31254 / 6Mo / 254SMO / F44
  • SMLS PIPE – ASTM / ASME / A312 / SA312 / UNS S31254 / 6Mo / 254SMO
  • FLANGES – ASTM / ASME / A182 / SA182 / F44 / 6Mo / 1.4547 / 254SMO
  • WELDED PIPE – ASTM / ASME / A358 / SA358 / UNS S31254 / 6Mo / 254SMO
  • PLATE – ASTM / ASME / A240 / SA240 / UNS S31254 / 6Mo / 254SMO
  • BAR – ASTM / ASME / A182 / SA182 / F44 / 6Mo / 1.4547 / 254SMO


by the following properties The steel is characterized

  • excellent resistance to pitting and crevice corrosion
  • high resistance to general corrosion
  • high resistance to stress corrosion cracking
  • higher strength than conventional austenitic stainless steels good weldability

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