| 摘要 |
PROBLEM TO BE SOLVED: To provide a method to provide the for continuous hot-dip metal coating by which the quality deficiency (plating defects) caused by metal vapor generated in a snout can be prevented at a low cost and equipment. SOLUTION: In carrying out hop-dip metal coating by continuously heat- treating a steel strip S in a continuous heat treatment furnace and introducing it into a plating bath 4 in which plating metal 5 is melted, a slit-like outlet hole 11 extending in the width direction of the steel strip is provided, at least to the upper wall surface, facing the top surface of the steel strip S, of the snout 3 disposed between the continuous heat treatment furnace 1 and the plating bath 4 and the metal vapor in the snout 3 is discharged out of the system via the slit-like outlet hole 11. The snout wall length from the lower end of the slit-like outlet hole 11 to the bath surface is made to <=h/(cosθ*sinθ)+300 mm (wherein, h is a distance (mm) between the upper wall surface of the snout and the steel strip; andθis the admission angle (deg) of the steel strip into the plating bath).
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