DUPLEX STAINLESS STEEL

摘要

Stainless steel duplex, comprises (in wt.%) a composition of carbon (= 0.05), chromium (21-25), nickel (1-2.95), nitrogen (0.16-0.28), manganese (= 2), molybdenum (= 0.45), tungsten (= 0.15), silicon (= 1.4), aluminum (= 0.05), copper (0.11-0.5), sulfur (= 0.01), phosphorous (0.04), boron (= 0.0005), cobalt (= 0.5), rare earth metals (= 0.1), vanadium (= 0.5), titanium (0.1), niobium (= 0.3), magnesium (= 0.1) and iron (rest), and impurities resulting from development, where the sum of molybdenum and tungsten/2 is >= 0.5. The microstructure is constituted by austenite and ferrite. Independent claims are included for: (1) preparation of the steel sheet comprising providing an ingot or a slab of the steel of the composition and hot roll of the ingot or slab at 1150-1280[deg] C to obtain a plate, a strip or a reel; (2) hot rolled steel quarto sheet, obtained by the process and having a thickness of 5-100 mm; (3) cold rolled steel band obtained by cold rolling a hot rolled reel obtained by the process; (4) preparation of a bar or a wire i.e. hot rolled from the given steel, comprising providing an ingot or a bloom of continuous casting of a steel, hot roll of the ingot or the bloom at 1150-1280[deg] C to obtain a bar i.e. cooled with air or a coil of wire i.e. cooled with water, then optionally thermal treatment at 900-1100[deg] C and cooling bar or the crown by hardening; (5) a hot rolled bar obtained by the process and having a diameter of 18-250 mm and hot rolled wire obtained by the process and having a diameter of 4-30 mm; (6) a cold drawn bar obtained by the process and having a diameter of 4-60 mm and drawn wire obtained by the process and having a diameter of 0.01-20 mm; (7) preparation of a steel section, comprising cold shaping of a hot rolled bar obtained by the process; (8) steel section obtained by the process; (9) preparation of a forged steel part, comprising passing the hot rolled steel bar into slug and forging the slug at 1100-1280[deg] C; (10) forged steel part obtained by the process; and (11) molded part obtained by molding of the steel.