Method of removing scales and preventing scale formation on metal materials and apparatus therefor

摘要

Suppression and removal of scales are efficiently carried out in a steel material hot rolling process and the time of pickling treatment as a successive step is greatly shortened. In a water cooling step of metallic material 11 at a temperature of 100° to 1,200° C., scales are removed by applying a direct current or an alternating current to metallic material 11 at 0.1 to 105 A/m2 of unit surface area from pinch rolls 2 to rolls 6 or apron guides 7 on the outlet side of a hot rolling mill 1 and/or by injecting cooling water at a pH value of -2 to 4 onto the metallic material 11 from cooling headers 4 and apron guides 7.