Manufacturing and Production

Hot Dip Galvanising Plant Operations

Hot dip galvanising gives steel decades of protection in one immersion, and the coating that results is decided almost entirely by the steel's own silicon content, which the galvaniser does not choose and often does not know. This course covers working with that. Delegates work through the metallurgy of the zinc iron reaction and the alloy layers formed, then through the silicon and phosphorus effects that produce thick, grey, brittle coatings on reactive steels. Surface preparation is covered through degreasing, pickling and fluxing, with the flux condition that decides whether zinc wets the steel. Kettle operation follows, including bath temperature, zinc chemistry, additions and dross and ash management. Jigging, immersion and withdrawal rate are addressed, along with the venting and drainage holes fabricators must provide. Coating thickness, appearance and standards conformity are covered. Defects are diagnosed: bare spots, dross inclusions, runs and wet storage stain. The course closes on kettle life, on zinc consumption and on safety around molten metal.