Surfacing welding method for enclosed connection of long-distance pipeline without mending

Abstract

The invention discloses a surfacing welding method for enclosed connection of a long-distance pipeline without mending. The technical scheme is characterized in that the long-distance pipeline is connected with a short joint, and the connection end opening between a prefabricated pipe A and a prefabricated pipe B in an enclosed manner; the connection end opening is subjected to surfacing operation by corrosion resistant alloy; a ladder-shaped corrosion resistant alloy surfacing method is adopted; a three-phase 'dead opening' butt joint method is adopted; a double-barrel four-electrode TIG is utilized for surfacing welding with corrosion resistant alloy; corrosion resistant alloy flux-cored wires MIG are utilized for backing weld; corrosion resistant alloy solid welding wires MAG are utilized for transition welding; with the composite welding method, ordinary carbon steel welding wires MAG are utilized for filling and capping in order to form the surfacing welding method for enclosed connection of the long-distance pipeline without mending.The technical scheme of the surfacing welding method for enclosed connection of the long-distance pipeline without mending has following beneficial effects: anti-corrosion continuity of the inner wall of the pipeline is ensured after the long-distance pipeline touches the dead opening; the conventional process of anticorrosive treatment for the inner wall of a welding seam is avoided when a widow is opened after the dead opening is touched; the window is not welded in an enclosed manner; no gap exists in an anti-corrosion layer of the inner wall of the window; and corrosion resistant performance and service life of the long-distance pipeline are improved.

Description

technical field [0001] The invention relates to a method for welding a closed connection of a long-distance pipeline, in particular to a method for surfacing and freeing the closed connection of a long-distance pipeline. Background technique [0002] The closed connection of long-distance pipelines refers to the process of welding and connecting steel pipelines constructed in sections through a section of short joints (dead joints), commonly known as "dead joints". [0003] Due to the characteristics of field construction, the straightness of the entire pipeline cannot be guaranteed when connecting two sections of pipeline with a "dead joint". [0004] In order to prevent and delay steel pipelines from being corroded by transported media (oil, gas, water, chemical products, etc.) The robot enters the interior of the pipeline and sprays anti-corrosion materials on the welds for anti-corrosion treatment (anti-corrosion repair). [0005] When two long-distance pipelines (gene...

AI Technical Summary

Problems solved by technology

The result of this method is that it is impossible to carry out anti-corrosion treatment on the inner weld seam of the welded "skylight" cover plate, which ha

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