Thermal treatment method for formed weld joint of drill rod

Abstract

The invention provides a thermal treatment method for a formed weld joint of a drill rod. The thermal treatment method comprises the following steps that firstly, annealing treatment is carried out on a weld joint zone which is formed between a drill rod pipe body and a connector through friction welding; then the annealed drill rod is placed in air to be cooled until the drill rod is cooled to the room temperature; and finally the cooled drill rod is subjected to tempering treatment. By means of the thermal treatment method, as tempering sorbite is formed, the structure of the weld joint of the drill rod is finer, and the problem of cracks in the weld joint of the small drill rod is completely solved.

Description

technical field [0001] The invention relates to the technical field of heat treatment of iron and steel materials, in particular to a heat treatment method for forming weld seams of drill pipes. Background technique [0002] At present, the forming of the drill pipe is mainly to form the weld seam through the friction welding process of the pipe body and the joint. The general process of the friction welding process is: joint inspection→pipe body appearance inspection→pipe body non-destructive inspection→pipe end processing→inertia friction welding→stress relief annealing→flash processing→quenching→tempering→weld area inspection→finished drill pipe weighing Weight, length measurement→welding wear-resistant band→labeling, packaging and delivery. [0003] In the prior art, the production of drill pipes with outer diameters of 88.9mm, 101.6mm, 127mm, and 139.7mm is usually the main method. The end of the welded drill pipe body needs to be thickened, and the thickness of the th...

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Problems solved by technology

[0004] In order to solve the above problems, in the existing heat treatment process, the concentration of the quenching liquid is usually increased to 7%. Tensile stress, when the maximum tensile stress exceeds its tensile strength, it is still prone to quenching cracks

That is, increasing the concentration of the quenching liquid from 3% to 7% did not bring good results in eliminating the formed weld, so only relying on increasing the concentration of the quenching liquid cannot fundamentally solve the crack problem of the small drill pipe weld

[0005] Therefore, a heat treatment process is needed to solve the problem of easy cracks in the production process of small drill pipe friction welding

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