Bushing-free narrow-gap pulse gas metal arc backing welding method of petroleum kelly bar

Abstract

The invention discloses a bushing-free narrow-gap pulse gas metal arc welding backing welding method of a petroleum kelly bar, which is used for solving the technical problem of poor welding quality caused by difficult operation while welding the petroleum kelly bar by the existing welding method. The method comprises the following steps: machining weld grooves of a left kelly bar and a right kelly bar to be welded into truncated edges which are matched with each other, and then forming narrow-gap grooves after the left kelly bar is aligned to the right kelly bar; and carrying out backing welding by utilizing a pulse TIG welding gun, and then carrying out filling welding by utilizing a pulse MAG welding technology until welding is completed. In the method, the truncated edges of the weld grooves are machined into cones and then matched with each other to form butt seams, and the upper parts of the truncated edges are machined into beveled edges which form a certain included angle withthe inner wall of a welding piece; the narrow-gap weld grooves formed by matching of the cones effectively inhibit weld penetration caused by rotation misalignment and welding deformation; and pulsedtungsten argon arc welding without filler wires is adopted to carry out backing welding, thus achieving simple operation and ensuring welding the seam quality of pulse TIG backing welding.

Description

technical field [0001] The invention relates to an oil drill collar welding method, in particular to an oil kelly narrow-gap pulse fusion extreme gas shielded welding method without a bushing. Background technique [0002] The existing narrow-gap pulse melting electrode gas-shielded automatic welding method (hereinafter referred to as MAG welding), in order to prevent the welding of the bottom layer and the excessive weld seam on the reverse side, when welding large thick-walled and small-diameter medium-carbon alloy structural steel pipe fittings For the height of the reinforcement, a bushing must be added to the inner wall of the pipe body. The bushing is generally made of refractory material. After the welding process is completed, the refractory bushing must be crushed and taken out. When this method is used to weld drill collars, the refractory liner needs to be crushed and taken out due to the thick and long wall of the pipe fittings, and the process is relatively comp...

AI Technical Summary

Problems solved by technology

[0007] In order to overcome the disadvantages of poor welding quality caused by the difficult operation of the existing welding method when welding the petroleum kelly, the present invention provides a non-liner backing welding method for the narrow gap pulse melting polar gas shielded welding of the petroleum kelly

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