METHOD FOR MANUFACTURING STEEL MATERIAL TO BE HOT-DIP GALVANIZED, AND STEEL MATERIAL TO BE HOT-DIP GALVANIZED

摘要

PROBLEM TO BE SOLVED: To provide a method for manufacturing a steel material to be hot-dip galvanized, which imparts excellent powdering resistance to the steel material and inhibits a problem from occurring on the surface layer of a slab after the slab is rolled and hot-dip plated; and to provide the steel material obtained by the manufacturing method. SOLUTION: The method for manufacturing the steel material 1 to be hot-dip galvanized comprises: a heating step of melting a zone between the surface and 4 mm deep layer therefrom of the continuously cast steel slab 2, by using one or both of induction heating and plasma heating; and a surface modification step of adding phosphor or a phosphorus alloy into a melt zone 5 melted in the heating step so that the concentration of phosphor in the melt zone 5 can be 0.02% or higher, to form a phosphor-concentrated region 3 on the surface layer of the slab 2. COPYRIGHT: (C)2007,JPO&INPIT