An all-position welding method for metal pipelines in a slope state

Abstract

The invention discloses an all-position welding method for metal pipelines in a slope state, which is suitable for the outdoor welding construction process of large-diameter long-distance oil and gas pipelines under the condition of slope undulating landforms. Including CMT outer root welding, filling welding and cover welding, for the construction conditions of all-position welding of pipelines under slope conditions, a consistent groove form and "inverted triangle" welding torch sway mode are adopted, eliminating the need for pipelines under slope conditions The tendency of the welding molten pool to flow down and the weld bead to be formed are smooth, which effectively solves the problem of unfused defects caused by the molten pool flowing down, and then solves the problem of automatic welding of pipelines under the slope state, greatly improving the welding efficiency and quality.

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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