Galvanised Steel Pipe: Steel Tube Pickled, Fluxed and Dipped in Molten Zinc

Galvanised pipe is steel tube with a coat of zinc. Pickle the tube in acid to take off the mill scale, rinse it, coat it with zinc ammonium chloride flux and let it dry, then dip it in molten zinc until it is as hot as the bath, lift it out and quench it. Dipping iron in zinc goes back to 1742; Sorel patented the acid and flux in 1836. The picture: our diagram of the four tanks.