Production manner null of alloy evaporation spelter metsuki

摘要

PURPOSE:To alloy vapor-deposited Zn to a steel strip without requiring a heating furnace for alloying by controlling the temp. rise of the steel strip by the heat of condensation of the vapor-deposited Zn and the heat transfer from a supporting roll at the time of depositing Zn by evaporation continuously on the steel strip in a vapor deposition chamber and forming the plating layer alloyed with the Fe of the steel strip. CONSTITUTION:The cold rolled steel strip 1 is annealed at 600-900 deg.C in a pretreatment furnace 2 and is subjected to a reduction treatment by gaseous N2 contg. 3% gaseous H2; thereafter, the steel strip is cooled and is taken out of the furnace 2 at =200 deg.C. The steel strip past a pressurizing chamber 3a and a sealing roll chamber 4a is wound on a heating roll 7 kept at 450-650 deg.C in a vacuum deposition chamber 5 and is subjected to the vapor deposition of the Zn by the Zn vapor from a molten Zn bath cell 6 and is then taken out after being passed through a sealing roll chamber 4b and a pressurizing chamber 3b. The temp. rise DELTAT1 of the steel strip by the heat of condensation of the vapor-deposited Zn and the temp. rise DELTAT2 by the supporting roll 7 of a high temp. are respectively controlled to maintain the steel strip temp. T3 after the vapor deposition of the Zn within the range expressed by equation [I], by which the Zn-Fe alloy layer consisting of the vapor-deposited Zn and the Fe of the steel strip is formed without using the heating furnace for alloying.