A NEW IMPROVED HIGH STRENGTH INTERSTITIAL-FREE STEEL

摘要

A method for making an interstitial-free steel comprising steps of casting a steel using composition as Carbon (C) = 0.001-0.003, Manganese (Mn) = 1.5-2.5, Sulphur (S) = 0.003-0.012, Phosphorus (P) = 0.07-0.12, Silicon (Si) = 0.05-0.4, Aluminum (Al) = 0.03- 0.1, Nitrogen (N) = 0.005-0.009, Titanium (Ti) = 0.01-0.05, Niobium (Nb) = 0.01- 0.05, Boron (B) = 10-40 ppm, rest Iron (Fe) (all in wt. %), soaking the steel at 1200-1220°C, hot rolling the steel at FRT 870-920°C, coiling the steel at 640-700 ° C, cold rolling the steel with 70-90% reduction, and continuous annealing the steel at 820 - 880 °C for 1-5 mins.