HOT ROLLING METHOD OF HIGHLY TOUGH STEEL MATERIAL USING THIN CAST SLAB

摘要

PROBLEM TO BE SOLVED: To provide a hot rolling method capable of producing a highly tough steel material by carrying out a hot rolling by using a continuously cast thin slab. SOLUTION: In the hot rolling method for a highly tough steel material by use of a thin cast slab having 155 mm or smaller thickness, the thin cast slab is a steel containing 0.01-0.50 mass % Nb, the rolling material is quenched in the way of hot rolling to form a bainite texture. Thereafter, the rolling material is reheated and hot rolled to the final thickness. The quenching is done by cooling with water down to 45 deg.C or below and is processed within 1.5-5 times in the ratio of the rolling material/finished thickness and the reheating temperature is set within 850-1050 deg.C.