METHOD FOR PREVENTING SURFACE CRACKING OF STEEL HAVING GAMMA-ALPHATRANSFORMATION

摘要

PURPOSE:To prevent the generation of surface cracking in a continuous casting ingot or the like of steel having gamma-alphatransformation during hot working in the stage of hot working said ingot by maintaining the surface temp. of the ingot at a specific temp. or above. CONSTITUTION:The surface temp. of a continuous casting ingot of steel having austenite-ferrite transformation, such as Si-Mn steel contg. 0.2% C, 0.15-0.5% Si, 0.6-1.8% Mn or V steel contg. =0.08% V in addition just prior to hot working is maintained at the Ar3 point of said steel or above and when the surface temp. decreases down to the Ar3 point or below, the ingot is reheated immediately up to the austenite temp. in the stage of subjecting said ingot to direct feed hot rolling. The generation of surface cracking in the steel material during hot rolling is obviated.