Continuous oil pipe steel strip butting technique

Abstract

The invention relates to a continuous oil pipe steel strip butting technique. The technique comprises the following steps: respectively cutting butt ends of two steel strips into a 45-degree end face, and polishing to remove rust; polishing end faces on two tab plates tangent to the steel strips to remove rust; aligning and compacting the butt ends of the steel strips, and spot-welding the butt ends of the steel strips by manual TIG welding to form a butt joint; respectively putting the tab plates on the head and tail of the butt joint of the steel strips, abutting the polished end faces of the tab plates against the two sides of the steel strips, and spot-welding the polished end faces of the tab plates by manual TIG welding for being fixed on the head and tail of the butt joint of the steel strips; carrying out backing welding by using a PLASMA welding technique; carrying out cosmetic welding by using the TIG welding technique; carrying out thermomechanical treatment on the butt joint; and removing the tab plates on the two sides of the welding seam. The invention combines the TIG welding technique with the PLASMA wire-filling welding technique, so that the welding seam has favorable toughness and plasticity. The invention enhances the fatigue strength of the continuous pipes, and prolongs the service life of the continuous pipes. The continuous oil pipe product has the advantages of stable performance and good quality.

Description

technical field [0001] The invention relates to a butt jointing process of coiled tubing steel strips. Background technique [0002] The steel strip butt joint and steel plate butt joint in the prior art include submerged arc welding, CO 2 Gas shielded welding, Ar 2 +CO 2 Mixed gas shielded welding, TIG welding, PLASMA welding and other butt joint processes. For the vast majority of steel pipe production, they are supplied according to the specified length. Reasonable control of the production process can save the joints at the end of the pipe or the end of the pipe for cutting. However, for the production of coiled tubing (COILED TUBING), the length of a single steel pipe is often 3000-5000m, or even more than 10,000 meters. Therefore, the quality of steel belt butt joint directly determines whether qualified coiled tubing products can be produced. Since the diameter of the coiled tubing is generally Φ19.1-114.3mm, it is generally produced by ERW (high-frequency straig...

AI Technical Summary

Problems solved by technology

It was not until 1987 that according to the process characteristics of ERW welded steel pipes, the 45°TIG oblique welding process was first used for steel strip butt jointing. However, due to the large number of welding passes, the wide heat-affected zone of welding, and low efficiency, it is not suitable for industrialized large-scale production.

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