Large diameter thick-walled seamless steel pipe refers to a pipe that out diameter is above 159mm. large diameter coated steel pipe is coated plastic made ​​on the basis of large diameter spiral welded pipe and high frequency welded pipe, the maximum nozzle diameter up to 1200mm. The large diameter seamless pipes according to the different needs of the coating of polyvinyl chloride (PVC), polyethylene (PE), epoxy (EPOZY) and other various properties of plastic coating, good adhesion, corrosion resistance , is resistant to acids, alkalis and other chemical corrosion. Non-toxic, does not rust, wear resistance, impact resistance, permeability, pipe a smooth surface will not adhere to any substance, can reduce the transmission of resistance, increase traffic and transport efficiency, reduce the delivery pressure losses. Solvent-free coating, no oozing substance, and thus will not the transmission medium of pollution in order to ensure the purity and health of the fluid at -40 ℃ to 80 ℃ range of hot and cold cycles of the use, no aging, no cracking, which can be used in the cold zone and other harsh environments. The large diameter seamless pipes are widely used in tap water, natural gas, petroleum, chemical, pharmaceutical, telecommunications, power, marine and other engineering fields.