Automatic welding method of nuclear island main pipes

Abstract

The invention relates to an automatic welding method of nuclear island main pipes. The diameter of a main pipe is more than or equal to 325mm, the wall thickness of the main pipe is more than or equal to 40mm. In the method, a prewelding combined groove is assembled by the relative end of the pipe parent metal, and the bottoms of a root truncated edge and a lower truncated edge are bottomed and welded to form root weld passes comprising a melt-through weld pass, a first fused weld pass, a second fused weld pass, a first support weld pass, a second support weld pass, a third support weld and a fourth weld pass; filling weld is carried out on the lower truncated edge and the upper groove to form a filling weld pass; the filling weld is carried out on the lower truncated edge and the upper groove again to form a last phase filling weld pass; and covering weld is carried out on the lower truncated edge and the upper groove by adopting a swinging weld pass and / or linear weld pass. The method of the invention can effectively ensure the welding quality and the welding thickness of the root weld passes, lays the foundation for the filling weld pass, has strong welding stability, can effectively avoid non-fusion phenomenon of the interlayers and the side walls, and has relatively better overall welding quality, short-period welding and high-efficiency welding.

Description

technical field [0001] The invention relates to the technical field of nuclear power, in particular to an automatic welding method for a main pipeline of a nuclear island. Background technique [0002] In a mega-kilowatt nuclear power project, the main pipeline is the main equipment, which is expensive and has a long manufacturing cycle, and the welding of the main pipeline is on the critical path of nuclear power construction. It is necessary to ensure the welding quality as high as possible and control it as short as possible. Welding cycle, thereby shortening the overall construction period of nuclear power plants. [0003] Automatic welding technology is an advanced welding technology, which has been widely used in equipment manufacturing, petrochemical and other fields. In the construction stage of nuclear power plants, the automatic welding of narrow gaps can not only greatly reduce the cross-sectional area of ​​the groove, greatly reduce the filling amount of welding...

AI Technical Summary

Problems solved by technology

[0008] 1. The root weld bead cannot guarantee the welding quality and welding thickness, and it is prone to defects that the root is not fused, and the filling bead is more prone to breakdown, and there is no repair measure;

[0009] 2. There is no timely treatment for the phenomenon of poor welding formation during the welding process, and it is more likely to have unfused defects on the side wall

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