Drill rod joint micro-annealing process

Abstract

A drill rod joint micro-annealing process comprises the steps: firstly plating copper on a drill rod joint having the surface without a phosphated layer, then carrying out tempering treatment, controlling the tempering temperature at 620 DEG C-690 DEG C, carrying out heat preservation for 100-140 min, and followed by carrying out water cooling to room temperature; for a joint having the surface with a phosphated layer, firstly pickling to remove the phosphated layer, then plating copper and carrying out tempering treatment. Aiming at the problem that comprehensive mechanical properties are decreased because the hardness value is often slightly higher in a conventional drill rod joint production, after the joint is treated, even if the hardness is dropped within a prescribed range of HB293-331, screw thread tooth deformation and surface decarburization of the joint can be prevented, the screw thread standoff requirement can be ensured, and the qualified rate of the product is improved.

Description

technical field [0001] The invention relates to a metal heat treatment process, in particular to a micro-annealing process. Background technique [0002] Drilling is first involved in the process of oil field exploitation. The main drilling tool is drill pipe, which is composed of drill pipe joint and drill pipe body. The hardness of the material of the drill pipe joint is generally longer than that of the machine. With the increase of the hardness value, the tensile strength and yield strength increase; when the hardness and Charpy impact energy increase value is greater than HB331, the tensile strength increases, but the yield strength increases. Strength and Charpy impact energy decreased. When the hardness value is too high, the comprehensive mechanical performance index decreases, the plasticity of the joint decreases, and it is easy to break. Only with high comprehensive mechanical performance can it be suitable for underground drilling. In the production of exis...

AI Technical Summary

Problems solved by technology

In the production of existing drill pipe joints, the hardness value is often on the high side. The traditional treatment methods are scrapping and tempering

However, tempering treatment can reduce the hardness, but the thread teeth on the joint are easily deformed, and a decarburization layer will be formed on the surface of the joint, resulting in unqualified joint thread tightness, and the final product is still unqualified, causing serious losses.