HOT ROLLING METHOD FOR STEEL FOR PREVENTING GENERATION OF SURFACE FLAW

摘要

PURPOSE: To provide a hot rolling method for steel for preventing the generation of a surface flaw in a method for blooming or rolling the steel deoxidized by Al without cooling it to a room temperature after a continuous casting. ;CONSTITUTION: Before blooming or rolling, the surface of an ingot is cooled to ≤500°C, and also, a shot is projected in the temperature area of ≤750°C at the time of reheating. Especially, in steel incorporating C, Si, Mn and Al of specific quantities, and also, one or ≥2 kinds of Cr, Mo, Ni and V, the surface of the ingot is cooled to ≤500°C before blooming or rolling, and also, at the time of reheating, the shot is projected in the temperature area of ≤750°C. In such a manner, transformation of a surface layer is advanced surely, γgrains are made fine and a grain boundary is strengthened, and a surface flaw such as a crack is obviated.;COPYRIGHT: (C)1993,JPO&Japio