There are two major categories of hot-dip galvanizing and electro-galvanizing. Hot-dip galvanizing includes wet method, dry method, lead-zinc method, redox method and the like. The main difference between different hot-dip galvanizing methods is how to activate the surface of the pipe to improve galvanizing quality after the pickling of steel pipes. The main production method is dry method and redox method. Zinc electroplated zinc surface is very smooth and dense, uniform structure; has good mechanical properties and corrosion resistance; zinc consumption is 60% to 75% lower than hot-dip galvanizing. Zinc electroplating has certain technical complexity, but this method must be used for single-sided plating, double-sided plating with different coating thickness on the inner and outer surfaces, and thin-walled tube galvanizing.
