What material is 254SMO stainless steel? Comparison of Chinese and foreign brands
254SMO stainless steel is an austenitic stainless steel. Due to its high molybdenum content, it has extremely high resistance to pitting and crevice corrosion. This grade of stainless steel was developed for use in environments containing halides such as seawater. 254SMO also has good resistance to uniform corrosion. Especially in acids containing halides, this steel is superior to ordinary stainless steel. Its C content is <0.03%, so it is 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, it is different from ordinary stainless steel in chemical composition. It refers to a high alloy stainless steel containing high nickel, high chromium and high molybdenum. Among them is 254SMo containing 6% Mo. This type of steel has very good local corrosion resistance. It has good pitting corrosion resistance (PI ≥ 40) and good corrosion resistance in seawater, air, gaps, and low-speed erosion conditions. It has excellent stress corrosion resistance and is a substitute material for Ni-based alloys and titanium alloys. Secondly, in terms of high temperature resistance or corrosion resistance, it has better high temperature resistance or corrosion resistance, which is irreplaceable for 304 stainless steel. In addition, from the classification of stainless steel, the metallographic structure of special stainless steel is a stable austenite metallographic structure.
Since this special stainless steel is a high-alloy material, the manufacturing process is quite complex. Generally, people can only rely on traditional processes to manufacture this special stainless steel, such as pouring, forging, rolling, etc.
The main components of 254SMO stainless steel: 254SMo contains carbon (C) ≤ 0.02, manganese (Mn) ≤ 1.00, nickel (Ni) 17.5 ~ 18.5, silicon (Si) ≤ 0.8, phosphorus (P) ≤ 0.03, sulfur (S) ≤ 0.01, 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-280
254SMO stainless steel supporting welding materials: ERNiCrMo-3 welding wire, ENiCrMo-3 welding rod
254SMO stainless steel application fields:
1. Ocean: Marine structures in the marine environment, seawater desalination, seawater aquaculture, seawater heat exchange, etc.
2. Environmental protection field: flue gas desulfurization equipment for thermal power generation, wastewater treatment, etc.
3. Energy field: atomic power generation, comprehensive utilization of coal, wave power generation, etc.
4. Petrochemical industry: oil refining, chemical equipment, etc.
5. Food field: salt production, soy sauce brewing, etc.
6. High concentration chloride ion environment: paper industry, various bleaching devices
254SMO stainless steel high temperature resistant
1. A large number of field experiments and extensive use experience show that even at slightly higher temperatures, 254SMO has high crevice corrosion resistance in seawater. Only a few types of stainless steel have this performance.
2. The corrosion resistance of 254SMO in acidic solutions and oxidizing halide solutions required for paper bleaching production is comparable to nickel-based alloys and titanium alloys with strong corrosion resistance.
3. Because 254SMO has a higher nitrogen content, its mechanical strength is higher than other types of austenitic stainless steel. In addition, 254SMO has high ductility and impact strength as well as good weldability.
4. The high molybdenum content of 254SMO allows it to have a higher oxidation rate during annealing, resulting in a rougher surface than ordinary stainless steel after pickling. But this has no adverse effect on the corrosion resistance of the steel.
Chemical composition of 254SMO stainless steel:
Carbon C: ≤0.02
Silicon Si: ≤0.70
Manganese Mn: ≤1.00
Phosphorus P: ≤0.03
Sulfur S: ≤0.01
Chromium Cr: 19.5 - 20.5
Molybdenum Mo: 6 - 7
Nickel Ni: 17.5-18.5
Copper cu: 0.5 - 1
Nitrogen N: 0.18 - 0.25
