Preparation method of plastic lining steel tube in welded connection

Abstract

The invention discloses a preparation method of a plastic lining steel tube in welded connection. The preparation method comprises the following steps: (1) peeling a section of a plastic preservative layer at the port of the plastic lining steel tube which is lined with plastic, wherein the port of the preservative plastic lining steel tube without the plastic is a connecting end of an outer steel tube; (2) lining the inner wall of the connecting end without the plastic preservative layer with a hot melt adhesive, wherein the hot melt adhesive is attached to the inner wall of the connecting end to form a hot melt adhesive layer; (3) inserting a stainless steel tube into the outer steel tube from the connecting end of the outer steel tube, wherein the outer wall of the stainless steel tube is bonded to the hot melt adhesive layer; and (4) then welding the outer wall of the stainless steel tube with the port of the outer steel tube. The plastic lining steel tube prepared by the method not only can effectively solve the problem of electrochemical corrosion after heterogeneous steel welding, but also can solve the structural problem that steel plastic tubes cannot be directly in welded connection, and the application of stainless steel in steel plastic tube manufacturing is expanded.

Description

Technical field [0001] The invention relates to a method for preparing plastic-lined steel pipes, in particular to a method for preparing plastic-lined steel pipes connected by welding. Background technique [0002] With the continuous expansion of the application fields of plastic-lined steel pipes, people have put forward higher requirements for the connection of plastic-lined steel pipes. The plastic-lined steel pipes currently available on the market basically use the traditional three connection methods of thread, groove or flange; but in some special fields such as industrial project fluid transportation pipes, petroleum and petrochemical buried long-distance pipelines, municipal underground pipe networks and other fields , Requires the use of welding connection, but also requires that the internal anti-corrosion layer of the pipeline cannot be destroyed. The traditional connection method cannot meet the above requirements; in the above field, the existing connection method...

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Problems solved by technology

[0004] In order to overcome the above-mentioned defects in the prior art, the present invention provides a method for preparing plastic-lined steel pipes connected by welding. This preparation method can not only effectively solve the problem of electrochemical corrosion of dissimilar steels after welding, but also solve the Structural problems that cannot be directly connected by welding expand the application of stainless steel in the manufacture of steel-plastic pipes

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