MANUFACTURING METHOD FOR STRIP CASTING 550 MPA-GRADE HIGH STRENGTH WEATHERING STEEL

摘要

A manufacturing method for strip casting 550 MPa-grade high strength weathering steel, comprising the following steps: 1) casting in a twin roll caster a 1-5 mm thick cast strip (11), where the chemical composition thereof in terms of weight percentage is that: C is between 0.03-0.08%, Si <= 0.4%, Mn is between 0.6-1.5%, P is between 0.07-0.22%, S <= 0.01%, N <= 0.012%, and Cu is between 0.25-0.8%, additionally, also comprised are more than one among Nb, V, Ti, and Mo, where Nb is between 0.01-0.08%, V is between 0.01-0.08%, Ti is between 0.01-0.08%, and Mo is between 0.1-0.4%, while the remainder is Fe and unavoidable impurities; 2) cooling the cast strip (11), where the cooling rate is greater than 20°C/s; 3) hot rolling the cast strip (11), where the hot rolling temperature is between 1050-1250°C, where the reduction ratio is between 20-50%, and where the deformation rate is > 205s-1; austenite online recrystallizing after hot rolling, where the thickness of the hot rolled strip is between 0.5-3.0 mm; 4) cooling, where the cooling rate is between 10-80°C/s; and, 5) winding, where the winding temperature is between 550-700°C. The microscopic structure of a steel strip acquired is primarily constituted by fine polygonal ferrite and pearlite.