Axial sealing anticorrusive internal and external covered non polar plastic steel pipe

A plastic-steel composite pipe with a butt-end packing and an outer plastic-lining comprises a composite pipe and a sealing connection pipe fitting, and is characterized in that: firstly, the composite pipe is a welding steel pipe with a inner lining of polyethylene plastic pipe and hot welt adhesive coated between the plastic pipe and a steel pipe; secondly, the composite pipe is a welding steel pipe with an outer cover of polyethylene plastic layer and hot welt adhesive coated between the plastic layer and the steel pipe; thirdly, the sealing connection pipe fitting consists of a connecting pipe, a stainless steel retaining ring and a silicone rubber sealing ring. Inner screw threads on both ends of the pipe fitting are arranged to match with outer screw threads of the composite pipe end, and an annular terrace is arranged at the tail of the inner screw thread of the pipe fitting; fourthly, the annular terrace supports the stainless steel retaining ring, and the silicone rubber sealing ring is positioned in the space between the stainless steel retaining ring and the inner wall of the pipe fitting; fifthly, a double sealing structure consisting of an outer pipe screw threads sealing and an inner silicone rubber ring sealing is formed when the inner screw thread of pipe fitting is screwed into the outer screw thread of the composite pipe and screw down to make the transverse plane of the composite steel pack down the silicone rubber sealing ring rightly. The utility model has the advantages of no scale formation, no contamination, corrosion resisting ability, reliable connection, high mechanical strength, leakage proof, high temperature resisting, and usability when being buried outdoors and so on.