| abstract |
An aspect of the present invention relates to a steel sheet comprising 10 to 20% by weight of a steel sheet comprising, by weight%, at least 0.9% of C, at least 0.5% of Si, at least 0.6% of Cr, 0.2 to 1.0% of Mn, balance of Fe and other unavoidable impurities, 17.8. The microstructure has an area fraction of 80% or more of pearlite. The pearlite has a softness and impact toughness of 20% or more of the area of a colony including a cementite having a stepped structure Pearlite steels. (Wherein C, Si and Cr in the above relational expression are values indicating the content of each element in weight%). |