| 摘要 |
PURPOSE:To prevent effectively the cracking to be generated during hot rolling by cooling the surface of the ultra-low carbon steel blank material contg. traces of >=1 kind among Nb, Ti, V, B, Al, Cr, P in particular down to a prescribed temp. or below during the hot rolling stage thereof. CONSTITUTION:The cracking during hot rolling of the ultra-low carbon steel contg., by weight, <=0.025% C, contg. >=0.002% each of Nb, Ti, V, B and contg. >=0.020% each of 1 kind among Al, Cr, P by utilizing the heat energy retained in the stage of casting said steel is prevented in the following way: The surface of said blank material is cooled to <=850 deg.C during the above-described hot rolling stage. As a result, the rolling cracking during the hot rolling is prevented without reheating the blank material after the above-described cooling or by using a min. of energy for reheating. |
