Method of controlling shape of internal upset transition zone free surface in oil drill pipe

Abstract

The invention discloses a method of controlling shape of internal upset transition zone free surface in an oil drill pipe, which uses an external mold (2) and a punch head (3) to carry out internal / external upsetting on a drill pipe (1); wherein, mold cavity of the external mold is provided with inner contour curve AB having the quadratic curve characteristics; the curvature of the contour curve AB of the mold cavity is controlled between 1.52 to 8.52m; the contour curve AB of the mold cavity and the clamping section BF of the external mold (2) are tangential at the crossover point; when carrying out internal / external upsetting, the drill pile is heated at the temperature of 1150 DEG C to 1250 DEG C and the heating length is 570-700mm. The invention proposes that curved surface of the mold cavity is used to guild, affect and control the flow direction of metal in the internal upset transition zone in the drill pipe. The invention ensures that the internal upsetting transition zone is smooth, continuous and fine in forming quality.

Description

Technical field [0001] The invention relates to a method for thickening the inside and outside of the pipe end of a drill pipe, and in particular to a method for controlling the free surface shape of the inner thickening transition zone of a petroleum drill pipe. Background technique [0002] Petroleum is called "the blood of industry". It is a widely used raw material in modern industry, modern agriculture and modern national defense, and it is also the most important kind of energy in the world at present. Drill pipe is an important part widely used in the oil drilling industry, and its performance is directly related to the success of the drilling operation. The main function of the drill pipe is to transmit torque, make the drill bit go down, and deepen the borehole. In addition to bearing torque, it is also subject to tensile stress generated by the weight of the string itself, and the tensile stress increases as the drilling depth increases. At the same time, high-pressure ...

AI Technical Summary

Problems solved by technology

[0012] In the current drill pipe production practice, the thickened end is often caused by improper mold structure or process design, especially local indentation, grooves, folds, lack of meat, and short length of the inner transition section at the inner transition of the thickened end (Miu) , small fillet radius R at the inner transition, etc., the product quality is unstable, and there is a big safety hazard in later use

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