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Alloy 254 Stainless Steel

Penn Stainless inventory now includes Alloy 254 SMO (UNS S31254) in sheet, sheet coil, plate, round bar, processed flat bar and tubular products.

General Properties

Alloy 254 SMO is a very high end, molybdenum and nitrogen alloyed super austenitic stainless steel with low carbon content. It demonstrates outstanding resistance to pitting, crevice corrosion stress cracking, and corrosion fatigue uniform corrosion. Alloy 254 SMO is substantially stronger than the common austenitic grades, with strength nearly twice that of 300 series stainless steel. It is also characterized by high ductility and impact strength. With high levels of chromium, molybdenum, and nitrogen, Alloy 254 SMO is frequently used in high chloride environments, such as brackish water, seawater, pulp mill bleach plants, and other chloride process streams. In some applications it has even been found to be a more cost effective substitute for high nickel and titanium alloys.

Applications:

Due to its high levels of molybdenum and nickel, Alloy 254 SMO is frequently used in high chloride environments. Examples of applications that call for the used of Alloy 254 SMO include:

  • Petroleum production
  • Saltwater handling
  • Food and chemical processing equipment
  • Pulp mill bleach systems
  • Flue gas desulphurization scrubbers
  • Tall oil distillation columns
  • Offshore oil & gas production equipment
  • Desalination equipment

Standards:

  • ASTM/ASME: UNS S31254
  • EURONORM: FeMi35Cr20Cu4Mo2
  • DIN: 2.4660

Corrosion Resistance

  • Excellent resistance to pitting and crevice corrosion due to its high chromium, molybdenum, and nitrogen content
  • Has a very low carbon content, which means there is very little risk of carbide precipitation during heating
  • Possesses very good resistance in water containing chlorides, therefore, it is suitable for use in seawater as it can be exposed to it for prolonged periods without suffering from crevice corrosion

Weldability

  • Possesses good weldability
  • Should be done without pre-heating
  • If correctly performed, there will be no need for any subsequent heat treatment
  • Has low thermal conductivity and high thermal expansion so must minimize distortion of welded joint
  • Welding without filler metal results in poor strength properties

Machinability

  • High work hardening rate combined with a lack of sulfur makes it very difficult to machine
  • Slow speeds, sharp tools, positive feeds, over-powered machine tools, and ample lubrication offer the best results

 

 

Chemical Properties:

% C Cr Mn Mo N Ni P Si S
254 SMO 0.02 max min: 19.5
max:20.0
1.00 max min: 6.0
max: 6.5
min: 0.18
max: 0.20
min: 17.5
max: 18.0
0.03 max 0.80 max 1.01 max

Mechanical Properties:

Grade

Tensile Strength ksi (MPa) min

Yield Strength 0.2%
Offset ksi (MPa) min
Elongation -
% in
50 mm (min.)
Hardness
(Brinell) MAX
Hardness
(Rockwell B) MAX
254 SMO Sheet & Strip 100 (690) 45 (310) 35 223 96
254 SMO Plate 95 (655) 45 (310) 35 223 96

Physical Properties:

Grade:

Alloy 254

Density

8.0 kg/dm3

Modulus of Elasticity

195 GPa

Linear Expansion
at 68to 212oF
(20 to 100oC)

16.5 X10-6/oC

Thermal Conductivity

 14 w/moC

Thermal Capacity

 500 J/kgoC

Electrical Resitivity

 0.85 μΩm

Call us at 1-800-222-6144 for more information