Hot dip coated steel strip - is preheated by electric resistance heating prior to immersion in molten zinc, lead or cadmium

摘要

The metal strip is degreased, pickled, washed, coated with flux, and preheated by direct electric resistance heating before travelling through a bath of molten metal. The strip travels over a roller forming one heating electrode, the second heating electrode being immersed in the bath of molten metal. The metal strip is pref. preheated to above the temp. of the molten bath; and a thermally-insulating channel fed with protective gas is pref. located between the roller, one side of the strip is pref. coated with flux, whereas the other side is covered with a layer inhibiting coating in the bath. Eliminates the need for a preheating furnace used in conventional coating processes.