A molten Al, Mg-containing Zn-plated steel sheet is contacted with steam in a closed vessel relates to a method for producing a black-plated steel sheet manufacturing apparatus and the manufacturing system may black-plated steel sheets more look uniformly blackening plating layer I will provide a.
A melt the surface of the base material steel plate Al, a closed container 10 having a Mg-containing Zn-plated layer disposed portion 12 of the plated steel sheet 1 can be arranged with a heating unit for heating the atmosphere gas inside the sealed container 24, an exhaust unit 30 that can exhaust the atmosphere gas inside of the sealed container to below atmospheric pressure, the water vapor introduction unit 40 for introducing the steam inside the sealed container, the atmosphere gas inside the sealed container a stirring unit 70 for stirring, a gas inlet 50 which dew point to introduce the plated steel sheet temperature below the gas, wherein the exhaust portion is capable of discharging the atmospheric gas containing water vapor from the interior of the sealed container apparatus for producing a black-plated steel sheet.
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