| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a hot-dip galvanized steel sheet with good surface appearance, which suppresses an occurrence of streaking defect. SOLUTION: The method includes steps of; setting a hot finish rolling temperature in a range of 1000 deg.C to Ar3 transformation temperature +20 deg.C in a hot rolling of a steel slab containing C: 0.0050 mass% or less, Si: 0.1 mass% or less, Mn: 0.05-0.6 mass%, Ti: 0.020-0.050 mass%, Nb: 0.003-0.010 mass%, B: 0.0002-0.0010 mass%, Al: 0.020-0.070 mass%, N: 0.0050 mass% or less, and iron and inevitable impurities for the rest; subsequently winding up at 700-820 deg.C; cold rolling; heat-treatment; and then hot-dip galvanizing treatment.
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