Hot dip IPN galvanized and PU paint Iron square pipes is a hollow strip steel, a large number of used for conveying fluid pipe, such as oil, natural gas, water, gas, steam, etc., in addition, doing bending and torsional strength phase at the same time, the weight is lighter, it is widely used in the manufacture of machinery parts and engineering structures.Also commonly used for the production of various kinds of conventional weapons, barrel, shells, etc.