| 摘要 |
PURPOSE: To manufacture a hot dip galvanized steel sheet excellent in appearance and adhesion by spray plating molten Al on a steel sheet surface at specific temperature in non-oxidizing atmosphere. CONSTITUTION: The steel sheet 1 which is pretreated and is heated at prescribed temperature is introduced into a plating room in a non-oxidizing atmosphere. In the first plating room 5, molten Al is spray plated on the steel sheet 1 while controlling temperature of both steel sheet and molten Al at 750-800 deg.C and a favorable wetting spread and a smooth Al plating layer is formed. Next, the steel sheet 1 is passed to a cooling room 7 and is cooled down to a prescribed temperature with a gas jet nozzle 4. Then, the steel sheet 1 is passed to the second plating room 6 and the molten Zn is spray plated with a spray nozzle 3 on the steel sheet 1 surface while controlling temperatures of both steel sheet 1 surface and the molten Zn at 450-600 deg.C. |
