| 摘要 |
PROBLEM TO BE SOLVED: To provide an apparatus capable of further preventing an oxide film from being formed on a surface of a zinc-aluminum based alloy plated (galvanized) steel sheet.SOLUTION: A nitrogen gas curtain 47 forming apparatus comprises a lower-stage nitrogen gas discharge bar 42 formed in a rectangular form around a plated steel sheet 1 which is lifted from the surface of a plating bath 3. The lower-stage nitrogen gas discharge bar 42 comprises: a side face cover 43 which takes in nitrogen gas from a nitrogen gas supply pipe on a side face to discharge the nitrogen gas toward the surface of the plating bath 3, and extends slopingly toward the plated steel sheet 1, from a side face of the lower-stage nitrogen gas discharge bar 42; and an upper-stage nitrogen gas discharge bar 44 arranged at the top end of the side face cover 43 and discharging the nitrogen gas 10 in a downward direction. The nitrogen gas curtain 47 forming apparatus thus forms a nitrogen gas curtain 47 around the plated steel sheet 1 to thereby prevent an oxide film from being formed on the surface of the plating bath 3.SELECTED DRAWING: Figure 5 |
