Steel pipe (steel-plastic composite pipe), also known as plastic composite pipe, composite pipe, is a new type of pipe, because as people raise awareness of environmental protection, world of increasingly stringent VOC control for environmental voice is also growing, PSP steel pipe has emerged. Plastic pipe is a pipe corrosion, both to maintain the strength of the steel pipe, but also played a characteristic of all kinds of plastic, thus the perfect combination of steel pipe, which has a vast market in the building materials industry. Plastic composite pipe products to seamless steel tubes, welded steel pipes for the base tube, polyethylene powder coating the inner wall of high adhesion, corrosion, food grade hygienic coating or epoxy paint. The use of pre-treatment, preheating, interior painting, leveling, water supply and galvanizing process in the post-treatment made of plastic composite pipe, galvanized pipe upgrade traditional products. Hot dip galvanized steel products standard name for the low pressure fluid hot-dip galvanized welded steel pipe, welded steel pipe is carried out on the basis of the internal and external hot galvanized steel pipe outer wall at the same time plated with zinc coating, pipe coating greatly improve performance and achieve common Pipe 20 times. Hot galvanized steel pipe as a delivery pipe or metal structure, fire engineering, natural gas, oil processing industry, water conservancy construction and residential construction and other widely used. The product reference to American Standard ASTM A53, the British standard BS1387, GB GB / T3091 and GB GB / T13793 use, should not be exposed for use in acid, alkali, salt and other non-neutral environment.