Positioning method for groove weld defects of large-wall-thickness pipe fitting

Abstract

The invention relates to a positioning method for groove weld defects of a large-wall-thickness pipe fitting. The positioning method comprises the following steps of: polishing the welding surface; marking a region; evaluating a negative film; drilling the marked part by utilizing a magnetic drill according to ultrasonic flaw detection depth; carrying out ultrasonic flaw detection to recheck the periphery; carrying out carbon arc gouging by utilizing a carbon rod until reaching the ultrasonic flaw detection depth; carrying out a process according to a welding process scheme made in advance; polishing the welding surface; carrying out penetration flaw detection, magnetic powder flaw detection or the ultrasonic flaw detection; polishing a groove weld part which needs to be subjected to radiographic flaw detection; carrying out the radiographic flaw detection. The positioning method is unique, provides a sufficient basis for the gouging and excavating depth and position of a defect and reaches a purpose of completely removing the defects in a carbon arc gouging manner.

Description

technical field [0001] The invention relates to a processing method for groove weld defects of large-wall pipe fittings, in particular to a positioning method for groove weld defects of large-wall pipe fittings. Background technique [0002] At present, for pipe fittings with large wall thickness, the maximum thickness of the butt groove of the pipe fittings is 210mm. After the pipe fittings are assembled and welded, the surface is ground, and the defects found after the radiographic flaw detection are mainly repaired by carbon arc gouging according to 1~2mm / layer. The standard is to find defects during the defect removal process. Once no defects are found during the defect removal process, it is possible to dig out the welded part or expand the area. It takes 1.2 hours to remove a defect on average. This operation removes defects The accuracy cannot be guaranteed, and the efficiency of removing defects is greatly reduced. The one-time removal rate of defects is 50%. [000...

AI Technical Summary

Problems solved by technology

[0002] At present, for pipe fittings with large wall thickness, the maximum thickness of the butt groove of the pipe fittings is 210mm. After the pipe fittings are assembled and welded, the surface is ground, and the defects found after the radiographic flaw detection are mainly repaired by carbon arc gouging according to 1~2mm / layer. The standard is to find defects during the defect removal process. Once no defects are found during the defect removal process, it is possible to dig out the welded part or expand the area. It takes 1.2 hours to remove a defect on average. This operation removes defects The accuracy cannot be guaranteed, and the efficiency of removing defects is greatly reduced. The one-time removal rate of defects is 50%

[0003] So far, there is no way to overcome the above drawbacks

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