THERMAL-REFINED HIGH TENSILE STRENGTH THICK STEEL PLATE AND METHOD FOR PRODUCING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a thermal-refined high tensile strength thick steel plate having excellent HIC resistance even after bending owing to the excellent ductility of the surface layer of the steel sheet, and further having sufficient strength and excellent bending workability as the whole, and a method for producing the same.;SOLUTION: A thick steel plate is discharged from a heating furnace under the conditions where, upon temperature rising of a thick steel plate, the surface temperature of the thick steel plate calculated by heat transfer calculation from heating conditions is A_c1+5°C to 1/2(A_c1+A_c3) temperature, and also, the average temperature of the region in ±2 mm from the central position of the plate thickness (the temperature calculated by heat transfer calculation from the heating conditions) satisfies below an A_c1, and is thereafter quenched and tempered.;COPYRIGHT: (C)2016,JPO&INPIT