Welded pipe and its manufacturing method

Abstract

The invention discloses a welded pipe manufacturing method which includes preprocessing two grooves of an area to be welded of a welded pipe with each groove comprising a first chamfer portion, a second chamfer portion and a truncated edge portion connected with the first chamfering portion and the second chamfering portion; conducting location seam closure on the welding pipe, enabling the truncated edge portions of the two grooves to coincide after the seam closure, and enabling the first chamfer portions of the two grooves to be connected to form a first groove opening and the second chamfer portions of the two grooves to be connected to form a second groove opening; welding the truncated edge portions through laser welding till the truncated edge portions are almost subjected to weld penetration; conducting single-run filling cosmetic welding on the first groove opening and the second groove opening through submerged-arc welding. According to the welded pipe manufacturing method, butt connection of the truncated edge portions of the grooves in the middle of a welding seam is achieved through laser welding, then the submerged-arc welding is utilized to achieve single-run welding, welding times are reduced, preheating and heat insulation are not required, welding production efficiency can be greatly improved, post-welding surplus seam height and lossless yield of the welding seam are higher than those in the prior art, and the performances of the welding seam such as strength, toughness and bending performance are better than those in the prior art.

Description

technical field [0001] The invention relates to the technical field of welded steel pipe production, in particular to a welded pipe and a manufacturing method thereof. Background technique [0002] Welded pipe refers to welded steel pipe, which is a steel pipe made of steel plate or strip steel after crimping and welding. After the steel plate is curled and formed, two adjacent plate edges are welded to form a welded pipe. The wall thickness of the welded pipe is generally 6mm-70mm, and the length is generally 3m-12m. Usually, the wall thickness is 30mm-70mm and belongs to the thick-walled welded pipe. [0003] The traditional thick-walled welded pipe manufacturing method is to process the area of ​​the welded pipe to be welded into an "X"-shaped groove, and then perform multi-layer and multi-channel automatic submerged arc welding on the groove. In order to ensure the weld seam quality of thick-walled welded pipes, especially to resist hydrogen-induced cracks, the shape of...

AI Technical Summary

Problems solved by technology

Due to deficiencies such as repeated welding and large amount of metal filling, it is difficult to greatly improve the welding efficiency, and the welding quality is poor, and defects such as pores and slag inclusions are prone to occur. If the temperature control is not good, cracks may even appear

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