1 Introduction
Material to F44 Super Austenitic Stainless Steel is described as a 6% Mo super austenitic stainless
What is UNS S31254? This grade of steel is a super austenitic stainless steel. They are high end stainless steel designed for impact toughness resistance to chloride crevice corrosion, stress corrosion cracking, and pitting. These are austenite with high content of nickel and chromium.
steel. 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 subzero 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. This alloy possesses a lower yield strength than that of duplex stainless steel (and much lower than that of super duplex steel) and pitting resistance which is comparable to super duplex stainless steel (such as UNS S32760 / S32750).

3 Quality Standard
ASTM A182 Standard Specification for Forged or Rolled Alloy-Steel Pipe Flanges, Forged Fittings, and Valves and Parts
EN 10088 part3 stainless steel

7 Corrosion Resistance
: F44 Super Austenitic Stainless Steel offers higher resistance to abrasion, erosion and cavitation erosion than other austenitic stainless grades such as 316. F44 Super Austenitic Stainless Steel has excellent resistance to corrosion in sea water and concentrated halide environments, with good resistance to crevice corrosion in seawater.

8 Welding
:F44 Super Austenitic Stainless Steel is readily weldeable with welding procedures used for other austenitic stainless steel specifications. Welding should be carried out at the lowest heat possible as due to its austenite structure it can be prone to hot cracking.

This material grade is usually provided in the annealed state offering yield strengths more than three hundred mega Pascal. This material cannot be strain hardened by heat treatment but harder surface toughness can be gained by cold working. The normal pitting resistance equivalent number of this alloy is forty two to forty four which makes sure that the resistance to pitting corrosion and crevice is high, enhancing this alloy as a substitute to the austenite alloys in 300 series (for example SUS304 type) in areas where mechanical properties are needed higher.
Available Forms in Market: Following are the available forms of S31254 steels in the global market:

Maximum percentage of Carbon (C) is 0.02 percent.
Maximum percentage of Manganese (Mn) is 1.0 percent.
Maximum percentage of Phosphorous (P) is 0.3 percent.
Maximum percentage of Sulphur (S) is 0.01 percent.
Minimum percentage of Chromium is 20.0 percent
Minimum percentage of Nickel is 18.0 percent.
Maximum percentage of Silicon (Si) is 0.7 percent.
Remaining is iron (Fe) percentage and with few negligible impurities.

Mechanical Properties of S31254 Steels: Following are some of the mechanical properties of UNS S31254 steels:

The tensile strength of the 254 alloy steel is expressed in Newton per millimeters and it must be at-least 600 N/mm2 (MPa).
The elongation property of S31254 steel varies with the heat treatment process but it indicated typically 50% at break.
S31254 is welded with filler materials like alloy 625.
The Brinell hardness is indicated around 210.
Corrosion resistance is higher than the other known austenitic grades.
Equivalent Material Grades in Other International Standards: Some equivalent standards are as under:

In SAE designation, the corresponding material is referred as 254 alloy.
In DIN standard, the corresponding material is referred as 1.4547 type steel.
Applications of S31254 Stainless Steels: Applications are as under:

F44 Super Austenitic Stainless Steel is ideally suited for use in halide environments and widely used in the chemical, marine, oil and gas industries. Typical applications include pumps, valves, heat exchangers, flanges and manifolds.


   AISI 8620 1,6523 | 21NiCrMo2 | SNCM220          20NiCrMo13-4 1.6660     ASTM 52100 | 1,3505 | 100Cr6 | SUJ2 | EN31       33NiCrMoV14-5 1.6956     

   AISI 4340 | 36CrNiMo4 | 1,6511 | EN24 | 817M40 | SNCM439      EN DIN 34CrNiMo6 | 1,6582 | 4337 Engineering Steel    BS EN 42CrMo4 | 1,7225 Alloy Steel  

   1,2379 | X153CrMo12 | SKD11      UNS S31254 1.4547 F44 Super Austenitic Stainless Steel      DIN 1.6657 14NiCrMo13-4 16NCD13 832M13 EN36C

   DIN1.6587 X4317 18CrNiMo7-6 17CrNiMo6 18NCD       DIN 1.6566 17NiCrMo6-4 18NiCrMo5 817M17 SAE4317       DIN 1.6657 14NiCrMo13-4 16NCD13 832M13 EN36C