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Short Description:
Stainless steel grade 254 SMO is a very high end austenitic stainless steel. It is designed with a combination of impact toughness resistance to chloride stress corrosion cracking, and pitting and crevice corrosion with strength that is twice that of the stainless steel 300 series.
Avliable Products: Wire, Pipe, Strip, Sheet, Plate, Flange,Bar
Product Description
254 SMO stainless steel, also known as UNS S31254, was originally developed for use in seawater and other corrosive chlorine environments. This grade is considered to be very high-end austenitic stainless steel; The main components are 19.5% to 20.5% chromium, 17.5% to 18.5% nickel, 6% to 6.5% molybdenum, and 0.18% to 0.22% nitrogen. These specific amounts of Cr, Ni, Mo and N in this “super austenitic” chemical composition enable 31254 to combine impact toughness against corrosion cracking with resistance to pitting and crevice corrosion. Its strength is almost twice that of 300 series stainless steel.
Due to the molybdenum content, UNS S31254 is often referred to as the “6% Molybdenum” grade; The 6% Moly series is able to withstand high temperatures and maintain strength under volatile conditions. The grade has gone beyond its original intent and overlaps with many industries, proving useful due to its high molybdenum content in other elements, which has enabled the 31254 to be successfully used in a variety of applications, such as flue gas desulfurization and chemical environments
Chemical Composition
| % | Ni | Cr | C | Mn | Si | P | S | Mo | Cu | N |
|---|---|---|---|---|---|---|---|---|---|---|
| min | 17.5 | 19.5 | - | - | - | - | - | 6 | 0.5 | 0.18 |
| max | 18.5 | 20.5 | 0.02 | 1 | 0.8 | 0.03 | 0.01 | 6.5 | 1 | 0.22 |
Physical Properties
| Properties | Metric | Imperial |
|---|---|---|
| Density | 8 g/cm3 | 0.289 lb/in3 |
Mechanical Properties
| Alloy | Tensile Strength MPa | Yield Strength (0.2% Offset) MPa | Elongation (%) |
|---|---|---|---|
| 254SMO | 650-850 | 300 | 35 |
Fabrication and Heat Treatment
Machinability
Stainless steel grade 254 SMO™ is quite tough to machine due to the extremely high work hardening rate and lack of sulfur content; however using sharp tools, overpowered machine tools, positive feeds, good amount of lubrication, and slow speeds tend to provide good machining results.
Welding
Welding of stainless steel grade 254 SMO™ requires filler material without which it results in poor strength properties. Filler metals such as AWS A5.14 ERNiCrMo-3, and alloy 625 are recommended. Electrodes used in the process, have to match with AWS A5.11 ENiCrMo-12.
Annealing
Annealing of this material should be performed at 1149-1204°C (2100-2200°F), which should be followed by a water quench.
Hot Working
Forging, upsetting and other operations relating to this material can be performed at 982 – 1149°C (1800 – 2100°F). It is recommended that temperatures do not exceed this range as it would result in scaling and reduction in the workability of the material. To re-attain maximum corrosion resistant properties, it is advisable to perform post-process annealing.
Cold Working
Cold working can be carried out using all the traditional methods; however the process would be tough due to its high work hardening rate. The result will provide the material with increased strength and toughness.
Hardening
Stainless steel grade 254 SMO™ does not respond to heat treatment. Hardening is possible only through cold reduction.
- Bars & Rods
- sheet & plate
- strip & coil
- welding wire &Spring wire
- Seamless tube & Welded pipe
» Round Bar & Square Bar & Hexagon Bar
Diameter : φ8～φ300mm
Length:10mm-6000mm
Hot forging,Hot Rolling,Cold Rolling
Bright Surface, Polished Surface, Black Surface
» Tube & Pipe:Seamless Pipe & Welding Pipe
Cold Drawing Seamless Pipe φ10～φ220mm
Hot Extrusion pipe:φ50～φ250mm
Others :U Blend Tube and Elbow
» Hot Rolled & Cold Rolled Plate Sheet
Thickness≦2.0mm Width:≦1500m
Thickness≧4.0mm Width:≦2500m
Length Within 6500mm
» Strip & Tape Ribbon
Thickness≧:0.01mm
Width：15mm-300mm
Cold rolling BA Strip, Hard & Soft Condition
» Straight Length Wire & Spool Wire
Welding Wire:ɸ0.1mm～6.0mm
Cut length Wire:φ1.0～φ8.0mm
Package:5-25kg/Spool
254 SMO Applications
- Saltwater handling
- Tall oil distillation columns
- Flue gas desulfurization scrubbers
- Components used in petroleum production
- Food processing equipment
- Process equipment in chemical industry
- Bleaching equipment in the pulp and paper industry
- Flue-gas cleaning
- Desalination
- Heat exchangers