Patent ID: 9677163
Date: 2017-06-13
CPC Classifications: C21D,C22C,C23C,Y10T

Claim:
1. A method of manufacturing a high strength galvanized steel sheet excellent in terms of coating adhesiveness comprising: performing an oxidation treatment on steel containing Si, Mn, and Cr in an oxidation furnace under a condition that an exit temperature T satisfies expressions below, performing reduction annealing, and performing a galvanizing treatment without performing an alloying treatment: where [Si]: Si content of the steel by mass %, and [Cr]: Cr content of the steel by mass %, wherein the oxidation furnace includes three or more zones in which atmospheres can be individually controlled and which are called oxidation furnace 1 , oxidation furnace 2 , oxidation furnace 3 and so on in ascending order of distance from the entrance of the furnace, in which atmospheres of the oxidation furnace 1 and the oxidation furnace 3 have an oxygen concentration of less than 1000 vol.ppm and the balance being N 2 , CO, CO 2 , H 2 O and inevitable impurities and the atmosphere of the oxidation furnace 2 has an oxygen concentration of 1000 vol.ppm or more and the balance being N 2 , CO, CO 2 , H 2 O and inevitable impurities.