| 摘要 |
The method comprises melting and casting of a multi-phase steel to a precursor containing iron and unavoidable impurities including carbon (0.14-0.25 wt.%), manganese (1.7-2.5 wt.%), silicon (1.4-2 wt.%), aluminum (less than 0.1 wt.%), chromium (less than 0.1 wt.%), molybdenum (less than 0.05 wt.%), niobium (0.02-0.06 wt.%), sulfur (up to 0.01 wt.%), phosphorus (up to 0.02 wt.%), nitrogen (up to 0.01 wt.%) and optionally an element consisting of titanium (up to 0.1 wt.%), boron (up to 0.002 wt.%) and vanadium (up to 0.15 wt.%), and hot rolling of the precursor. The method comprises melting and casting of a multi-phase steel to a precursor containing iron and unavoidable impurities including carbon (0.14-0.25 wt.%), manganese (1.7-2.5 wt.%), silicon (1.4-2 wt.%), aluminum (less than 0.1 wt.%), chromium (less than 0.1 wt.%), molybdenum (less than 0.05 wt.%), niobium (0.02-0.06 wt.%), sulfur (up to 0.01 wt.%), phosphorus (up to 0.02 wt.%), nitrogen (up to 0.01 wt.%) and optionally an element consisting of titanium (up to 0.1 wt.%), boron (up to 0.002 wt.%) and vanadium (up to 0.15 wt.%), hot rolling of the precursor starting at an initial temperature of 1100-1300[deg] C and ending at a final temperature of 820-950[deg] C to obtain a hot band, coiling the hot bands in a coiling temperature of 530-600[deg] C, optionally annealing the hot bands, annealing of the hot band as a batch type annealing or continuous annealing at 400-700[deg] C, cold rolling the hot bands at cold rolling degrees of 50-70% to obtain the cold-rolled product, heat treating the resulting cold-rolled product by continuously annealing the cold-rolled product at an annealing temperature of 800-830[deg] C for 10-300 seconds, and over-aging the cold-rolled product at an aging temperature of 370-460[deg] C for 800 seconds. The heat treatment comprises cooling of the cold-rolled product at an intermediate temperature of 500[deg] C at a cooling rate of 5[deg] C/seconds. The cold-rolled product is assigned with a metallic or organic protective layer. Independent claims are included for: (1) a multi-phase steel; and (2) a cold-rolled product. |
