What is 254 SMO Stainless Steel
254 SMO stainless steel belongs to super austenitic stainless steel, and its EN/DIN grade is 1.4547, UNS grade is S31254, and domestic grade is 00Cr20Ni18Mo6CuN. It is one of the standard hexa-molybdenum alloy steels. This kind of stainless steel is developed for halide and acid environments.
Since the carbon of 254 SMO stainless steel is very low, it means that heating will merely cause the risk of carbide precipitation.
For 254 SMO stainless steel, it can still pass the Strauss intergranular corrosion test (Strauss Test ASTMA262 Protocol E) for one hour after sensitization when the temperature is at 600 to 1000 degrees Celsius. However, due to its high content of alloy, the metallic mesophase may be precipitated at the grain boundary within this temperature range. These precipitates will not expose the steel to the risk of intergranular corrosion when it is used in corrosive media. Therefore, it can be used for welding, and no intergranular corrosion will occur. And its matching electrode is EnICRMO-3 and the matching wire is ErNICRMO-3. But in hot concentrated nitric acid, these precipitates may cause intergranular corrosion in the heat-affected zone.
In solutions containing compounds like chloride, bromide, or iodide, the ordinary stainless steels will immediately be corroded in the form of pitting, crevice, or stress corrosion cracking. However, in some cases, the presence of halides can accelerate uniform corrosion, especially in non-oxidizing acids with halides.
In pure sulfuric acid, 254 SMO performs much better in corrosion resistance than 316L does. However, compared with 904L (NO8904) stainless steel at high concentration, 254 SMO performs less weaker in its corrosion resistance. In sulphur-acid solution containing chloride ions, 254 SMO can show a powerful resistance to corrosion. Due to possible partial or uniform corrosion, normal 316L cannot be used in hydrochloric acid. But when in normal temperature, 254 SMO can be applied in diluted hydrochloric acid. For pitting corrosion, if it is under the critical line, there is no need to worry about. However, crevice corrosion must be avoided.
For general stainless steel, they have very limited performance on corrosion resistance when putting in fluosilicic acid (H2SiF4) and hydrofluoric acid (HF). And 254 SMO stainless steel can be used in a wide range of concentrations and temperatures.
Advantages of 254 SMO Stainless Steel
254 SMO stainless steel has good pitting resistance (PREN≥43) and stress corrosion resistance under seawater, aeration, gap and low speed scouring conditions, and it can be a substitute material for Ni-based alloy and titanium alloy. Besides, it has a better performance under high temperature or on its corrosion resistance. And since it has a high content of nitrogen, this kind of stainless steel also performs better than other kinds of austenitic stainless steel on the mechanical strength and wear resistance. Its low content of nickel also makes it become cost-effective. In addition, 254 SMO stainless steel has high ductility and impact strength as well as good weldability.
Therefore, it is believed that 254 SMO is a rare and cost-effective super stainless steel.
Application of 254 SMO Stainless Steel
- a) Petroleum; Petrochemical equipment, such as the bellows.
- b) Pulp and paper bleaching equipment, such as pulp digester, bleaching equipment, filter scrubber barrel and press roller, etc.
- c) Flue gas desulfurization device in power plant: body of absorber tower, flue, door panels, inner parts, spray system, etc.
- d) Offshore systems or sea water treatment, such as thin-walled condensing pipes cooled by sea water in power plants, desalination equipment, even in equipment where sea water may not flow.
- e) Desalination industry, such as salt or salt removal equipment.
- f) Heat exchanger, especially for the one working in the chloride ion environment.
What We do for 254 SMO SS
We provide 254 SMO tubes, pipe fittings, flanges etc, it is also availabe to do customized items on the requirements. You are welcome to contact us if you have requirements.
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