METHOD FOR MANUFACTURING ZINC COATED STEEL SHEET HAVING EXCELLENT COATING ADHESION AND ZINC COATED STEEL SHEET PRODUCED USING THE SAME

摘要

The present invention relates to a method to manufacture a galvanized steel sheet having excellent coating adhesion, and a galvanized steel sheet manufactured thereof. According to an embodiment of the present invention, the method to manufacture a galvanized steel sheet having excellent coating adhesion comprises: a step of preparing a matrix steel sheet; a step of primary heating the matrix steel sheet at a heating rate of 2.5-4.5 C/s at 500-650C by charging the prepared matrix steel sheet to a non-oxidation furnace; a step of secondary heating the primary heated matrix steel sheet at 750-850C in a reducing atmosphere; a step of cooling the secondary heated matrix steel sheet; and a step of forming a galvanized layer on the matrix steel sheet by dipping the cooled steel sheet in a plating bath. In the primary heating step, a gas comprising at least one selected from a group consisting of 16-50 volume% of CO_2, residual N_2, H_2O, and CO is charged to the non-oxidation furnace.