At the start of external blasting and wiping of zinc, it is required to double the gas flow to ensure that the galvanized steel pipe enters the gas field. There are two reasons for this:
(1) The end of the galvanized steel pipe that exits the molten zinc first cools in the air for a longer period. Therefore, the galvanized layer solidifies quickly. To achieve the purpose of increasing the blasting and wiping force and to smooth out the excess zinc liquid on the nearly solidified galvanized layer, a larger gas flow is necessary.
(2) When the galvanized steel pipe has not yet entered the nozzle ring opening, the gas diffuses rapidly and cannot be concentrated on the top of the pipe end for blasting and wiping. Therefore, the blasting and wiping force is insufficient, and it is necessary to increase the gas flow to correct this. Once the galvanized steel pipe enters the nozzle ring opening, the gas is effectively blown onto the outer surface of the galvanized steel pipe, significantly increasing the blasting and wiping force. At this point, the gas flow can be appropriately reduced.
