Heat treatment method for attachment weld between hand hole pipe and end cap of pipeline

Abstract

The invention discloses a heat treatment method for an attachment weld between a hand hole pipe and an end cap of a pipeline. The hand hole pipe (2) is connected to an outer circumferential wall and / or an end wall of a blind end of the pipeline (1), a free end of the hand hole pipe (2) and the end cap (3) are connected by welding through the attachment weld (4). The heat treatment method comprises the following steps: S1, an outer end face of the end cap (3) is connected to an auxiliary pipe (6); S2, a heating element (9) is arranged and surrounds the periphery of the hand hole pipe (2), the end cap (3), and the auxiliary pipe (6); S3, the heating element (9) is started for carrying out heat treatment of the attachment weld (4). The end cap of the hand hole pipe is connected to the auxiliary pipe, so that the heating area of the attachment weld at one side of the end cap can be prolonged, so that the heating temperatures at double sides of the attachment weld are kept consistent, and heat treatment quality is improved.

Description

technical field [0001] The invention relates to a heat treatment method, in particular to a heat treatment method for a welding seam connecting a hand hole pipe and an end cover of a pipeline. Background technique [0002] At present, various headers used in pressure pipelines such as the four major pipelines of large-scale power plant units (main steam pipeline, reheat steam hot section pipeline, reheat steam cold section pipeline, and main water supply pipeline), including economizer system headers, water-cooled Wall headers, superheater system headers, reheater system headers, etc. [0003] In order to meet the needs of unit manufacturing, inspection and maintenance, large-diameter pipes such as pressure pipes and headers are usually provided with hand hole pipes, through which hand holes can be inserted into the pipes for related operations. Such hand-hole pipes are mostly welded during production. If post-weld heat treatment is required, the entire large-diameter heade...

AI Technical Summary

Problems solved by technology

[0004] However, when the unit is put into production and service, when inspecting the inside of the header and pipeline, it is necessary to cut the end of the hand hole pipe, and then perform welding and heat treatment again after the inspection, and the site does not have the overall heat treatment of the pipeline and header into the heat treatment furnace conditions, only partial heat treatment

For example, heating sheets can be wrapped around the hand hole tube, but the heating load in this heating method is not uniform, and the heat treatment effect is not good

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