Method for manufacturing hot-dip galvanized steel sheet, eliminating descale process with excellent corrosion resistance and plating adhesion

摘要

The present invention is a manufacturing process of hot-dip galvanized hot-rolled steel sheet without removing the scale layer formed on the surface of the hot-rolled steel sheet in pickling and galvanizing line in the steelmaking process by pickling process or mechanical peeling process By reducing the scale layer of the hot rolled sheet in the reduction heating table installed before the plating bath in the middle, it reduces the environmental problems and manufacturing cost caused by the removal of hot rolled scale and at the same time maintains the aluminum concentration of the plating bath appropriately. The present invention relates to a method for manufacturing a plated hot rolled steel sheet. More specifically, in the manufacturing process of a hot-dip galvanized hot rolled steel sheet, the step of eliminating the hot rolled scale layer located at the side of the reduction heating zone is omitted, and the reduction heat treatment temperature is reduced at a hydrogen atmosphere of 10% or more at a temperature of 550 to 820 ℃, holding time of heat treatment 30 ~ 120 seconds or more depending on heat treatment temperature 400 Reducing the surface scale layer of the hot-rolled steel sheet to maintain below, and coating the reduced-treated hot-rolled steel sheet by plating in a plating bath containing 0.3 to 5.0wt.% Of aluminum And a descaling step omitted hot dip galvanized hot rolled steel sheet having excellent plating adhesion.