SMO254 (UNS S31254) six molybdenum stainless steel
Product name: SMO254/UNS S31254
International common names: 254SMO, UNS S31254, W.-Nr. 1.4547, F44, NAS 185N, 00Cr20Ni18Mo6CuN, 6Mo
Implementation standards: ASTM A240/ASME SA-240, ASTM A276, ASTM A182/ASME SA-182, ASTM A312/ASMES A312
Main ingredients: 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, nitrogen (N) 0.18 ~ 0.22
Physical properties: 254SMO density: 8.24g/cm3, melting point: 1320-1390 ℃, magnetic properties: none
Heat treatment: heat preservation between 1150-1200℃ for 1-2 hours, rapid air cooling or water cooling.
Mechanical properties: Tensile strength: σb≥655Mpa, Yield strength σb≥310Mpa: Elongation: δ≥35%, Hardness: 182-223 (HB)
Corrosion resistance and main use environment: 254SMO stainless steel is a highly corrosion-resistant super austenitic stainless steel, developed for environments with halides and acids, and is widely used in harsh working conditions such as high-concentration chloride ion media and seawater. In various industrial situations in acidic media, especially in acids containing halides, 254SMO is far superior to other stainless steels, and in some cases can be comparable to Hastelloy and titanium. The lower carbon content and high molybdenum content make it have good resistance to pitting corrosion and crevice corrosion, and excellent resistance to intergranular corrosion. It is a cost-effective stainless steel that is widely used in the fields of chemical industry, desulfurization and environmental protection at home and abroad. widely used.
In pure sulfuric acid, 254SMO has much greater corrosion resistance than 316 ordinary stainless steel. However, compared with 904L (NO8904) stainless steel at high concentrations, the corrosion resistance of 254SMO is slightly weaker. Among sulfuric acids containing chloride ions, 254SMO has the greatest corrosion resistance. Due to the possibility of local corrosion and uniform corrosion, 316 ordinary stainless steel cannot be used in hydrochloric acid, but 254SMO can be used in dilute hydrochloric acid at normal temperatures. There is no need to worry about pitting corrosion in areas below the boundary line. But efforts must be made to avoid the existence of gaps. In fluorosilicic acid (H2SiF4) and hydrofluoric acid (HF), the corrosion resistance range of ordinary stainless steel is very limited, while 254SMO can be used in a fairly wide range of concentration and temperature.
Supporting welding materials and welding processes: 254SMO welding uses high-quality 625 alloy series welding materials, namely ERNiCrMo-3 welding wire and ENiCrMo-3 welding rod. The welding material sizes are Φ1.0, 1.2, 2.4, 3.2, and 4.0. The origin is: Kazakhstan, the United States. , American SMC and Deutsche Nickel, please call us for welding procedures and instructions.
Inventory status: The stock sizes of 254SMO stainless steel plates are 0.5mm-18mm, and the stock sizes of bars are Φ12mm-Φ250mm. Pipes, fittings and others can be customized according to customer requirements. The main origins of materials include Japan Metallurgy, Japan's Nippon Steel and Sumitomo Metal and Sweden's OUTOKUMPU. Provide original material certificate, customs declaration form and certificate of origin.
Application fields include: petroleum and petrochemical equipment, such as bellows in petrochemical equipment, pulp and paper bleaching equipment, such as pulp digesters, bleaching equipment, barrels and pressure rollers for filter scrubbers, power plant flue gas desulfurization equipment, mainly The parts used include: tower body, flue, baffle plate, internal parts, spray system, etc. of the absorption tower, offshore systems or seawater treatment, such as thin-walled condensation pipes cooled by seawater in power plants, seawater desalination treatment equipment, even in seawater It can also be used in equipment that may not flow, the desalination industry, such as salt production or desalination equipment, heat exchangers, especially heat exchangers in working environments with chloride ions.
