Metal pipe all-position welding method in gradient state

Abstract

The invention discloses a metal pipe all-position welding method in a gradient state, and is suitable for outdoor welding construction procedures of large-drift-diameter oil long transmission pipes under gradient fluctuation landform conditions. The method comprises CMP outer root welding, fill welding and cosmetic welding; and aiming at pipe all-position welding construction conditions in the gradient state, consistent groove forms and an inverted triangle welding gun yaw mode are adopted to eliminate the dripping tendency of a welding molten bath in the gradient state of the pipes, so that awelding bead is flatly molded, the problem of no melting caused by dripping of the molten bath is effectively solved, the difficulty of automatic welding of the pipes in the gradient state is solved,and the welding efficiency and quality are greatly improved.

Description

technical field [0001] The present application relates to the field of pipeline welding, in particular to an all-position welding method for metal pipelines in a slope state. Background technique [0002] When the pipeline is automatically welded at all positions under the slope state, the welding torch usually adopts the angle pendulum or trapezoidal torch transport method, but because the welding pool is greatly affected by the oblique component of gravity, the metal in the molten pool is easy to fall from the groove wall above. Drip to the groove wall below, causing unfused welding defects between the molten iron flowing down and the groove wall below, which is also a difficult problem in the field of all-position automatic welding of pipelines. [0003] At present, the method to solve this problem is: design the pipe butt joint groove as an asymmetric groove, that is, increase the angle of the upper groove wall, reduce the angle of the lower groove wall, and then increas...

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Problems solved by technology

[0004] However, the disadvantage of the above methods is that the processing of asymmetric welding grooves greatly increases the processing difficulty and the number of machines and tools for prefabrication of pipes before welding, which reduces the construction efficiency, and the state of the molten pool formed by this process is unstable. There is still a phenomenon of inclined dripping on the surface of the weld seam, and the tendency of the surface inclination becomes more and more serious with the increase of the wall thickness of the metal pipe

Therefore, the current pipeline automatic welding equipment is rarely used in the welding operation of long-distance oil and gas pipelines under the condition of undulating slopes.

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