| 摘要 |
A method for manufacturing a high strength galvanized steel sheet including a Si- and Mn-containing steel sheet, as a base steel sheet, and having excellent coating appearance, coating peel resistance at severe forming, and formability and a high strength galvanized steel sheet are provided. A high strength galvanized steel sheet having a zinc coating layer with an amount of deposition of coating of 20 to 120 g/m 2 per one surface on the surface of a base steel sheet having a chemical composition comprising C: 0.03% to 0.35%, Si: 0.01% to 0.50%, Mn: 3.6% to 8.0%, Al: 0.001% to 1.000%, P ‰¤ 0.10%, S ‰¤ 0.010%, and the balance comprising Fe and incidental impurities, on a percent by mass basis, is produced. At this time, in annealing and galvanization treatment of the base steel sheet in a continuous galvanizing line, the maximum steel sheet temperature in an annealing furnace is 600°C or higher and 750°C or lower, the steel sheet transit time in a temperature region of the maximum steel sheet temperature of 600°C or higher and 750°C or lower is specified to be 30 seconds or more and 10 minutes or less, and the dew point in an atmosphere is specified to be -10°C or higher. |
