Method for manufacturing longitudinal submerged arc welded pipe

Abstract

The invention provides a method for manufacturing a longitudinal submerged arc welded pipe, which comprises the following steps of: adjusting the position of a welded pipe during pre-welding, rotating the groove position of the welded pipe from 12 o'clock position to 6 o'clock position, correspondingly rotating nine groups of row rollers of a joint closing machine by 180 degrees, rotating a 9 # roller from 12 o'clock position to 6 o'clock position, and rotating a 9 # roller from 12 o'clock position to 6 o'clock position by 180 degrees; a joint closing row roller of the joint closing machine applies main power and acts on the circumference of the steel pipe and the vicinity of a groove, and pre-welding treatment is carried out. The pre-welding device is changed from the 12 o'clock position outside the welded pipe to the 6 o'clock position inside the welded pipe. Therefore, the problems that in the prior art, the welded pipe is tracked and then pre-welded after coming out of the row roller of the sewing machine, the welded pipe is pre-welded after being slotted to different degrees, misalignment and weld beading are prone to being generated, and tracking of an inner welding cutter wheel is affected by the weld beading are solved. In addition, the submerged-arc welding of the welded pipe adopts a manner that outer submerged-arc welding is firstly carried out and then inner submerged-arc welding is carried out by submerged-arc automatic welding, so that the inner welding quality is improved, the repair of an inner welding seam is reduced, the qualification rate is greatly improved, and the repair cost is also reduced.

Description

technical field [0001] The invention belongs to the technical field of welding pipe manufacturing methods, and more particularly relates to a manufacturing method of a straight seam submerged arc welded pipe. Background technique [0002] Welded pipes, also known as welded steel pipes, are steel pipes made of steel plates or strips after cold forming and welding, and are widely used in all walks of life. [0003] During the joint and automatic welding in the manufacturing process of the LSAW pipe, pre-welding is performed on the outer groove at the 12 o'clock position of the LSAW pipe, and then the inner submerged arc automatic welding is carried out, and finally the outer burial is carried out. Arc automatic welding. [0004] The straight seam submerged arc welded pipe uses the above-mentioned seam and automatic welding methods, and the welded pipe needs to be tracked and then pre-welded after coming out of the seam machine row roller, which will cause the forming seam to ...

AI Technical Summary

Problems solved by technology

[0005]The object of the present invention is to provide a method for manufacturing longitudinal submerged arc welded pipes, aiming at solving the problem of pre-preparation when the forming seam is not reliably controlled in the seaming machine. During welding, it is easy to pre-weld after opening the seam, resulting in misalignment and weld bead, which will affect the tracking of the inner welding knife wheel. In addition, since the inner submerged arc welding is performed first and then the outer submerged arc welding is performed, the heat input of the inner submerged arc welding When the amount is large, there will be a risk of burn-through, and the small heat input will increase the defect risk of internal submerged arc welding, and the repair of internal welding defects will be affected by the space, which will increase the difficulty and cost of rework

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