METHOD FOR ANTI-SURFACE CHECK ON HOT ROLLED CONTINUOUS CASTING PEACES WITH DECOMPRESSED WIDTH PRESSURE

摘要

PROBLEM TO BE SOLVED: To prevent the occurrence of surface checks on cased pieces by continuous casting of the steel which contains specific amounts of Mn, Nb, N, and Fe at a specified surface temperature, and by giving depressor drawing ratio is of specified percentage, also by retaining then during a specified time, and then by conducting hot rolling at a specified temperature when the process is completed. ;SOLUTION: Casting pieces are obtained by a continuous casting of steel of a percentage by weight which contain; 0.5-2.0 Mn, 0.01-0.02 S, 0.02-0.06 Nb, and 0.002-0.01 N, also meets a relation of a content ratio of Mn and S to be (% Mn)/(% S)≥50, and the remains are substantially Fe. Before the temperature of the casting pieces drops under 900°C, the casting pieces are inserted into a heating furnace to be reheated to 1050-1250°C. It is retained during 5 minutes when temperature to be at 1050-1200°C and are depressed to be more than 3% from perpendicular direction. After that, the hot rolling is conducted at the terminated temperature to be higher than 900°C.;COPYRIGHT: (C)1998,JPO