| 摘要 |
Provided is a method for manufacturing a galvanized steel sheet at a high product yield ratio having good surface appearance without surface defects by using a high-Si-containing steel sheet as a base steel sheet. A method for manufacturing a galvanized steel sheet excellent in terms of surface appearance quality and coating adhesiveness, characterized by comprising;
heating a base steel sheet in a heating zone such that the surface of the base steel sheet is heated at a temperature of 600°C or higher and 790°C or lower while a furnace temperature T°C in the heating zone of an annealing furnace is controlled based on the water vapor partial pressure P H2O in Air of air fed into the heating zone, the base steel sheet having a chemical composition consisting of, by mass%, C: 0.05% or more and 0.25% or less, Si: 0.1% or more and 3.0% or less, Mn: 0.5% or more and 3.0% or less, P: 0.001% or more and 0.10% or less, Al: 0.01% or more and 3.00% or less, S: 0.200% or less, and the balance being Fe and inevitable impurities,
heating the base steel sheet in the heating zone such that the surface of the base steel sheet is heated at a temperature of 630°C or higher and 850°C or lower in an atmosphere containing hydrogen gas having a partial pressure P H2 of 1000 Pa or more and 50000 Pa or less, water vapor gas having a partial pressure P H2O of 610 Pa or less, and the balance being N 2 and inevitable impurities, and galvanizing the base steel sheet. |
