165-steel-grade drill rod weld joint heat treatment method

Abstract

The invention discloses a 165-steel-grade drill rod weld joint heat treatment method. A drill rod weld joint is formed by conducting friction welding on a drill rod connector and a drill rod pipe body, the steel grade of the drill rod connector is 135 ksi, and the steel grade of the drill rod pipe body is 165 ksi. The 165-steel-grade drill rod weld joint heat treatment method comprises the steps of 1 quenching, 2 first-time tempering and 3 second-time tempering, wherein during the second-time tempering of the step 3, the center of a tempering coil is aligned to the position, deviating from one side of the pipe body, of the weld joint for 8-12 mm. The 165-steel-grade drill rod weld joint heat treatment method reduces the side hardness of the weld joint pipe body and makes the structure of a whole welding area more uniform, better comprehensive mechanical properties are obtained, and the service life is prolonged.

Description

technical field [0001] The invention relates to the technical field of petroleum drill pipes. Background technique [0002] With the development of oil drilling technology, the drilling depth is getting deeper and the well body structure is becoming more and more complex, and the performance requirements for oil drill pipes are also getting higher and higher. In order to meet the needs of drilling technology, at present, the strength of the drill pipe body has been increased to 165ksi. 165 steel grade drill pipe is welded together with 165ksi drill pipe body and 135ksi drill pipe joint by friction welding process. The chemical composition of the 165ksi drill pipe body material is: C: 0.22~0.25%, Si: 0.22~0.28%, Mn: 0.40~0.55%, P:≤0.010, S≤0.005, Cr: 0.95~1.10%, Ni: 0.55~0.65%, V: 0.13~0.17%. The chemical composition of 135ksi drill pipe joint material is: C: 0.35~0.38%, Si: 0.15~0.25%, Mn: 0.85~0.95%, P:≤0.013, S≤0.005, Cr: 1.10~1.20%, Ni:≤ 0.25%, V: ≤0.03%. Due to the ...

AI Technical Summary

Problems solved by technology

Due to the different chemical composition and heat treatment process of the drill pipe body and the drill pipe joint, the mechanical strength, material hardness and other properties of the drill pipe body and the drill pipe joint are quite different. Larger materials are friction welded together, and conventional heat treatment of drill pipe welds can easily lead to excessive hardness of the weld on the side of the pipe. Usually, the hardness of the welding zone section is ≥ 40HRC (technical requirements ≤ 37HRC), and along the circumferential direction of the drill pipe The impact toughness of the weld (at -20°C) is not uniform, and the impact value fluctuates greatly

The current heat treatment method for drill pipe welds only includes two steps of quenching and tempering, without special treatment for materials with large differences on both sides of the weld, which will cause excessive hardness of the weld pipe body and uneven impact toughness of the weld , Practical problems that affect the service life

Images