| 摘要 |
PROBLEM TO BE SOLVED: To provide an alloying furnace outlet side gas-atomized fog cooling method capable of preventing generation of gas-atomized fog wrinkles caused by super-cooling, preventing generation of flickering flaws by zinc powder caused by insufficient cooling, and obtaining alloyed galvanized steel sheet having excellent quality. SOLUTION: A plurality of stages of gas-atomized fog cooling means 1, 2 are installed on the outlet side of an alloying furnace to alloy a hot-dip galvanized steel sheet 3 to perform the rapid cooling. Though the cooling rate has been uniform in the vertical direction in the known technology, the cooling in a second stage is slower than the cooling in the first stage. For example, the best result can be obtained by setting the cooling rate in the first stage and the cooling rate in the second stage to be set 30-35°C/sec. and 20-25°C/sec., respectively. COPYRIGHT: (C)2006,JPO&NCIPI
|
