Overview
254SMo is an austenitic stainless steel, developed for use in halide-containing environments such as seawater. The superiority of this steel manifests itself especially in halide-containing acids. 254SMo also features good resistance to uniform corrosion. As its carbon content is less than 0.02%, it is called pure austenitic stainless steel; when its carbon content is less than 0.01% , it can also be called super austenitic stainless steel.
Features of Inox 254SMo
Super stainless steel is a type of special stainless steel. First of all, unlike ordinary stainless steel, it is a high-alloy stainless steel containing high nickel, high chromium and high molybdenum. The most well-known one is 254SMo with 6% Mo. Due to high molybdenum content, this stainless steel features very good local corrosion resistance. Plus, it features good resistance to pitting corrosion (PI ≥ 40) and stress corrosion when used in harsh conditions like seawater, aeration, gap and low speed scouring. Therefore, it can be a great substitute to nickel-based alloys and titanium alloys. Secondly, it embodies excellent high-temperature resistance and corrosion resistance, which 304 stainless steel cannot match. In addition, from the classification of stainless steel, the metallographic structure of special stainless steel is a stable austenitic metallurgical structure.
According to the results of a large number of field experiments and extensive experience, 254SMo has high crevice corrosion resistance in seawater, even at slightly higher temperatures. Only a few types of stainless steel embody this property. In acidic solutions and oxidizing halide solutions necessary for paper bleaching, 254SMo demonstrates strong corrosion resistance, comparable to that of the most corrosion-resistant nickel-based alloys and titanium alloys.
Due to the high nitrogen content, 254SMo features better mechanical strength than other types of austenitic stainless steel. In addition, 254SMO features high ductility, impact strength and good weldability. The high molybdenum content contained within allows 254SMO to acquire a high oxidation rate during annealing, resulting in a rougher surface than common stainless steel after pickling. However, this does no harm to the corrosion resistance of this stainless steel.
Specification
| Standard | UNS | Werkstoff Nr. | EN | SS | AFNOR |
| 254 SMO | S31254 | 1.4529 | X1CrNiMoCuN20-18-7 | 2378* | Z1 CNDU 20.18.06AZ* |
Chemical properties
The chemical composition of stainless steel grade 254 SMO™ is outlined in the following table.
| Element | Content (%) |
| Iron, Fe | 55.69 |
| Chromium, Cr | 20 |
| Nickel, Ni | 18 |
| Molybdenum, Mo | 6.1 |
| Nitrogen, N | 0.20 |
| Carbon, C | 0.010 |
Mechanical properties
The following table shows mechanical properties of stainless steel grade 254 SMOTM.
| Properties | Metric | Imperial |
| Tensile strength | 680 MPa | 98600 psi |
| Yield strength | 300 MPa | 43500 psi |
| Modulus of elasticity | 195 GPa | 28300 ksi |
| Shear modulus | 75 GPa | 10900 ksi |
| Poisson’s ratio | 0.30 | 0.30 |
| Elongation at break | 50 % | 50 % |
| Hardness, Brinell | 210 | 210 |
- 254SMo Applications
- 1) Ocean: marine structures in the sea environment, seawater desalination, marine aquaculture, seawater heat exchange, etc.;
- 2) Environmental Protection: flue gas desulfurization device for thermal power generation, wastewater treatment, etc.;
- 3) Energy: atomic power generation, comprehensive utilization of coal, and ocean wave power generation.;
- 4) Petrochemical Industry: refining, chemical equipment;
- 5) Food: salt making, soy sauce brewing, etc.;
- 6) High concentration chloride ion environment: paper industry, various bleaching devices;
- 7) Others.
Tags
Grade 254SMo, Type 254SMo, Inox 254SMo, AISI 254SMo, SUS 254SMo, 1.4547, UNS S31254, Acero 254SMo.
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254SMO Super Stainless Steel Plate UNS S31254 Sheet Smo 254 Equivalent Images
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