Type 904L is low in carbon content (0.020% Max), no carbide is precipitated under normal heat treatment and welding conditions. It has good activation-passivation transformation ability and excellent corrosion resistance. It has good corrosion resistance in non-oxidizing acids such as sulfuric acid, acetic acid, formic acid and phosphoric acid. It has good pitting resistance in neutral medium containing chloride ions, and has good crevice corrosion resistance and stress corrosion resistance. The steel is widely used in petroleum, petrochemical equipment, seawater treatment equipment, paper industry equipment, sulfuric acid, nitric acid equipment, acid making, pharmaceutical industry and other chemical equipment, pressure vessel, food equipment and so on.