HIGH STRENGTH THIN COLD-ROLLED SHEET VIA COLD ROLLING PROCESS AND METHOD FOR MANUFACTUREING THE COLD-ROLLED SHEET

摘要

PURPOSE: A high-strength ultra-thin steel sheet using cold rolling and a method for manufacturing the same are provided to secure improved strength of a steel sheet by adding Mn and B. CONSTITUTION: A high-strength ultra-thin steel sheet using cold rolling comprises carbon(C) of 0.15-0.25 weight%, manganese(Mn) of 1.5-2.5 weight%, silicon(Si) of 0.1-1.0 weight%, titanium(Ti) of 0.01-0.05 weight%, boron(B) of 5-30ppm, phosphorus(P) of 0.01-0.08 weight%, and iron(Fe) and inevitable elements of the remaining amount. The organization of the ultra-thin steel sheet comprises bainite 70vol% or more and the rest ferrite. The product of C, Mn, and B contents satisfies the following equation: 1.1310^(-4) wt% C wt% Mn wt% B 1.87510^(-3).