The air-cooling duration is actually a crucial factor. Neglecting this factor can affect the production output and quality of hot-dip galvanized steel pipes. Therefore, it must be carefully considered. When selecting parameters, the following two aspects should be taken into account:
(1) When the zinc dipping time is short, the molten zinc temperature is low, the steam temperature for internal blasting and wiping of zinc is low, the wall thickness of the galvanized steel pipe is thick, and the room temperature is low, a longer air-cooling duration can be appropriately adopted.
(2) When the zinc dipping time is long, the molten zinc temperature is high, the steam temperature for internal blasting and wiping of zinc is high, the wall thickness of the galvanized steel pipe is thin, and the room temperature is high, a shorter air-cooling duration can be appropriately adopted.
