STEEL SHEET WITH LESS WELDING DISTORTION

摘要

PURPOSE: A steel sheet is provided to reduce the welding distortion of the steel sheet as a microstructure contains 25 area% or more of processed ferrite. CONSTITUTION: A steel sheet is composed of 0.03-0.2 wt.% of C, 0.05-0.40 wt.% of Si, 0.5-1.80 wt.% of Mn, 0.005-0.1 wt.% of Al, 0.001-0.01 wt.% of N, 0.001-0.050 wt.% of P, 0.001-0.050 wt.% of S, and the rest of Fe and other inevitable impurities. A microstructure contains 25 area% or more of processed ferrite. The rest structure contains polygonal ferrite, pearlite, bainite, and martensite. The total of the bainite and the martensite is 10 area% or less. [Reference numerals] (AA) Martensite structure; (BB) Processed ferrite structure(80% cold rolled);