C3-80 refers to the martensitic stainless steel 1Cr17Ni2 or 2Cr17Ni2, with a tensile force of 800 N/mm2. 1Cr17Ni2 series is a kind of steel with better strength and toughness among martensitic stainless steels. It has good corrosion resistance to oxidizing acids, most organic acids and aqueous solutions of organic salts. It is generally suitable for the production of nitric acid and acetic acid, as well as for shafts, piston rods, pumps and other parts that require both toughness and corrosion resistance in light industry, textile and other industries.