Composite steel pipe with flange and manufacturing method thereof

The invention discloses a flannel composite steel pipe and manufacturing method, which is characterized by the following: (1) the outer galvanizing steel pipe or inner liner film stainless steel pipe forms inner liner stainless steel composite steel pipe through diameter reducing or enlarging; (2) when the composite steel pipe and flannel adapt screw connection, the flannel lining part contains silicon gel sealing ring; when the pipe body tightens the flannel through screw, the pipe body end clings the silicon gel sealing ring; (3) the inner layer of inner lining stainless steel pipe is film wall stainless pipe, which is welded with flannel through stainless steel bar; when the composite steel pipe with flannel is assembled, the fluid in the pipe and stainless steel pipe and welding gap touch; (4) two ends of polythene plastics is closed through chuck in the heat air stove through grafting heat melting gel, which is blown into lining composite pipe; (5) the end part of lining composite pipe with flannel is blown into bellmouthing shape, whose end is blown to cling the flannel end face to form flannel end face plastic-covering layer; the inner pipe wall and flannel end form the integral plastic-covering layer.