ASTM GRADE：UNS S31254
EU GRADE：W.-Nr. 1.4547
ASTM STANDARD：ASTM A240/ASME SA-240[SCALE STEEL]、ASTM A276、ASTM A182/ASME SA-182、ASTM A312/ASMES A312
254SMO is one kind of super austenitic stainless steel. Because of its high molybdenum content, it has high resistance to spot corrosion and crevice corrosion. This brand of stainless steel has been developed for use in halide containing environments such as sea water. 254SMO also has good resistance to uniform corrosion. Especially in the acid containing halide, the steel is superior to ordinary stainless steel. Its C contains <0.03%, so called pure austenitic stainless steel (<0.01% is also called super austenitic stainless steel). Super stainless steel is a kind of special stainless steel, first of all, different from ordinary stainless steel in chemical composition, refers to a kind of high alloy stainless steel [SCALE STEEL]containing high nickel, high chromium, high molybdenum. One of the more famous steels is 254SMo containing 6%Mo. This kind of steel has very good local corrosion resistance, and has good pitting resistance (PI≥40) and good stress corrosion resistance under the condition of seawater, aeration, crevice and low-speed scouring. It is the substitute material for Ni-based alloy and titanium alloy. Secondly, in the performance of high temperature resistance or corrosion resistance, has more excellent high temperature resistance or corrosion resistance, is irreplaceable 304 stainless steel. In addition, from the classification of stainless steel, special stainless steel metallographic structure is a stable austenite metallographic structure.
Because this special stainless steel is a kind of high alloy material, so in the manufacturing process is quite complex, generally people can only rely on the traditional process to make this special stainless steel, such as perfusion, forging, calendering and so on.
Main ingredients: 254 smo carbon (C) 0.02 or less, manganese (Mn) of 1.00 or less, nickel (Ni) 17.5 ~ 18.5, silicon (Si) of 0.8 or less phosphorus [SCALE STEEL](P) of 0.03 or less, sulfur (S) of 0.01 or less, chromium (Cr) 19.5 ~ 20.5, copper (Cu) 0.5 ~ 1.0, molybdenum (Mo) 6.0 ~ 6.5
National standards: UNS S31254, DIN/EN 1.4547, ASTM A280, ASME SA-240
Supporting welding material: ErnicRMO-3 wire, ENICRMO-3 electrode
1. Ocean: Marine construction of Marine environment, seawater desalination, mariculture, seawater heat exchange, etc.
2. Environmental protection: thermal power plant flue gas desulfurization device, wastewater treatment, etc.
3. Energy: nuclear power generation, [SCALE STEEL]comprehensive utilization of coal, tidal power generation, etc.
4. Petrochemical industry: refining, chemical and chemical equipment, etc.
5. Food: salt making, soy sauce brewing, etc.
6. High concentration of chloride ion environment: paper industry, various bleaching devices
High Temperature Resistance:
1. Extensive field experiments and extensive experience in use have shown that 254SMO has very high create-corrosion resistance in seawater, even at slightly higher temperatures, and only a few types of stainless steel have this property.
2. The corrosion resistance of 254SMO in acidic and oxidizing halide solutions, such as those used in paper bleaching, is comparable to[SCALE STEEL] that of nickel base alloys and titanium alloys, which are the most resistant.
3. Due to its high nitrogen content, 254SMO has higher mechanical strength than other types of austenitic stainless steels. In addition, 254SMO has high ductility and impact strength as well as good weldability.
4. The high molybdenum content of 254SMO enables it to have a higher oxidation rate during annealing, resulting in a rougher surface after pickling than ordinary stainless steel. But this has no adverse effect on the corrosion resistance of the steel.
Chemical Composition for 254SMO, UNS S31254 Super Austenitice Stainless Steel:
254SMO Density：8.24g/cm3， Melting Point：1320-1390 ℃，Magnetism：None, Hardness：182-223（HB）