METHOD AND APPARATUS FOR PRODUCING VAPOR DEPOSITED AND GALVANIZED STEEL SHEET ALLOYED ON ONE SIDE

摘要

PURPOSE:To product a vapor deposited and galvanized steel strip which is alloyed on one side and of which the plating face on the thinly coated side is subjected to Fe-Zn alloying by plating Zn by vapor deposition at different thicknesses continuously on both faces of cold rolled steel strip then heating the plating face on the thinly coated side by a heating roller. CONSTITUTION:The cold rolled steel strip 1 is pretreated by annealing and gas reduction in a pretreatment furnace 2 and is then cooled by a gas jet cooler 3. The steel strip is thereafter passed through a pressurizing chamber 4 and a 1st sealing roll chamber 5a and is introduced into a 1st vacuum deposition chamber 6a where the strip is wound around a roll 8a and Zn vapor is stuck on the face not in contact with the roll 8a. The Zn is thus plated on said face by vacuum deposition. The steel strip is in succession introduced into a 2nd vacuum deposition chamber 6b where the steel strip is turned upside down and is wound on a roll 8b. The Zn is thus plated by the vacuum deposition on the non-plated face. The strip is in succession introduced into a heating roll chamber 9 where the thinly coated side of the Zn plating is wound in the heating roll 9a and is heated. The Zn plating face on the thinly coated side is thus subjected to the Fe-Zn alloying with Fe of the steel strip.