Equivalent designations UNS S31254 DIN W. Nr. 1.4547 Form ASTM Rod, bar and shape A 276, A 484 Plate, sheet and strip A 240, A 480 Seamless and welded pipe A 312, A 999 Welded pipe A 814, A 999 Seamless and welded tubing A 269, A 1016 Fitting A 403, A 960 Forged or rolled pipe flange and forged fitting A 182, A 961 Forging A 473, A 484 Chemical composition % Fe Cr Ni Mo C Mn Si P S Cu N min balance 19.5 17.5 6.0 0.50 0.18 max 20.5 18.5 6.5 0.020 1.00 0.80 0.030 0.010 1.00 0.22 Physical properties Density 7.94 g/cm3 Melting range 1320-1390℃ Features: 254 SMO is a high performance austenitic stainless steel. Its high alloying elements content imparts excellent resistance to uniform, pitting and crevice corrosion, and stress corrosion cracking. It was originally developed to withstand the corrosion of acids, especially in the presence of halide ions, such as hydrochloric acid, hydrofluoric acid, phosphoric acid, and sulphuric acid contaminated with chlorides. In certain environments it is an alternative to more expensive nickel alloys and titanium alloys. Applications: Chemical processing equipment, pulp and paper industry bleaching equipment, desalination plant seawater piping, food and beverage industry, pharmaceuticals, and hydrometallurgy.