Large-diameter seamless steel pipe is a steel pipe with an outer diameter of 1000 mm or more. The steel pipe is made by punching a steel ingot or a solid pipe blank, and then made by hot rolling, cold rolling or cold drawing. The large-diameter seamless steel pipe is made by coating plastic on the basis of large-diameter spiral welded pipe and high-frequency welded pipe. The maximum nozzle diameter is 1200mm. It can be coated with PVC and PE according to different needs. ), epoxy resin (EPOZY) and other various properties of plastic coating, good adhesion, corrosion resistance, resistant to strong acid, alkali and other chemical corrosion, non-toxic, no rust, wear, impact resistance, Permeability is strong, the surface of the pipeline is smooth, no substance is attached, the resistance during transportation can be reduced, the flow rate and the transmission efficiency can be increased, and the pressure loss of the transmission can be reduced. There is no solvent in the coating, no leakage of substances, so it will not contaminate the transported media, so as to ensure the purity and sanitation of the fluid. It can be used alternately in the range of -40°C to +80°C, without aging, Because it does not crack, it can be used in harsh environments such as cold areas. Large-caliber coated seamless steel tubes are widely used in tap water, natural gas, petroleum, chemical, pharmaceutical, telecommunications, electric power, marine and other engineering fields.