| 摘要 |
PURPOSE:To improve the surface properties of a hot dip galvanized steel sheet by bringing rolls heated to a surface temp. above the temp. of the steel sheet into direct contact with the steel sheet to carry out alloying. CONSTITUTION:A continuously annealed steel sheet 6 is dipped in a molten zinc bath in a hot dip galvanizing pot 2 through a snout, the forward direction is changed by a sink roll and the steel sheet 6 is pulled up from the bath, and is continuously metalized. A gas is blown on the continuously hot dip galvanized steel sheet 6 from wiping nozzles 4 to remove excess molten zinc, and the steel sheet 6 is introduced into a heating zone for alloying. In the heating zone, the steel sheet 6 is heated by bringing plural heated rolls 10 into direct contact with the steel sheet 6 to carry out alloying. The heating zone is kept in a nonoxidizing atmosphere by introducing a nonoxidizing gas from an inlet 12.
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