Method and device to prevent surface defects caused by zinc powder in a process of continuous strip galvanization

摘要

Procedure to prevent surface defects caused by zinc powder on the metal strip galvanized in a process of continuous galvanizing of strip, which moves through a nose nozzle furnace (1) a metal strip (2) heated in a continuous furnace, under protective gas, and immersed in a zinc bath (3), wherein the upper and lower side of the metal strip (2) received in the nose nozzle furnace (1) , shielding gas through openings insufflation (11/07), and wherein the shielding gas loaded with zinc vapor and / or zinc dust is sucked through suction openings (07.21) which are arranged on both sides of the metal strip (2) adjacent to the openings insufflation (11/07), characterized in that a majority of the openings insufflation (7.11) is configured and arranged in the nose nozzle furnace (1) so Thus, the protective gas flowing from these abertu ras insufflation (11/07) is directed towards the surface of the metal strip (2), turned towards the respective opening insufflation (11/07), with an angle of incidence in a range between 70 ° and 110 °, preferably between 80 and 100 °, where the distance between the opening insufflation (7.11) respectively and at least one suction opening (7.21), associated therewith, are selected such and the flow rate of the protective gas leaving the opening insufflation (7.11) respectively is controlled such that it counteracts a protective gas entrainment in the direction of the zinc bath (3), which occurs during movement of the metal strip (2).