1. galvanized steel pipe to make the molten metal react with the iron matrix to produce an alloy layer so that the matrix and the coating are combined. hot-dip galvanizing is to pickle the steel pipe first. to remove the iron oxide on the surface of the steel pipe, after pickling, it is cleaned by ammonium chloride or zinc chloride aqueous solution or a mixed aqueous solution of ammonium chloride and zinc chloride and then sent to a hot-dip galvanizing tank. the advantages of galvanized pipe are uniform coating, strong adhesion, and long service life. hot-dip galvanizing is because many companies now reduce the thickness of the galvanized layer for profit. the original theoretical life is 7-8 years, and now the product quality can only be guaranteed for two or three years.
2. fire-fighting plastic coated steel pipe is a combination of steel pipe and plastic, which can be used for pipes of any diameter. the connection method is not limited to the screw connection of galvanized pipe, groove connection, but also welding connection, flange connection, bimetallic welding connection, etc. the emergence of plastic-coated steel pipes solves the above problems. it has the strength of steel pipe. corrosion resistance, strong coating adhesion, good impact resistance, suitable for normal work in harsh natural environments. long service life, more than five times that of galvanized pipes.