A Punch Die for Forming Thickened End of Petroleum Drill Pipe and Its Application

Abstract

The invention relates to a convex die for forming the thickened end of a petroleum drill stem and application of the forming convex die. The convex die comprises a convex die rod and convex die blocks, an outer thread is arranged at the front end of the convex die rod, inner thread sections are arranged on the inner sides of the convex die blocks, the three convex die blocks are enclosed to form a complete convex die ring, the inner thread sections on the three convex die blocks are enclosed to form an inner thread matched with the outer thread, and the convex die ring is of a hollow frustum structure. Compared with the prior art, the combined split convex die is applied to drill stem forming process, the forming process of the inner surface transition area of the thickened end of the drill stem can also be controlled by the die, the problem of inner surface quality caused by the fact that the area can only be controlled by the process parameters including the strain rate, strain force, the deformation volume and temperature in the past is solved, meanwhile the forming quality of the outer surface can further be improved, the problem that the wall thickness and the surface quality of the transition area of the thickened end of the drill stem cannot be controlled by a traditional upsetting die is solved, the drill stem with the thickness of the transition area of the thickened end changes uniformly is obtained, and the service life of the drill stem is prolonged.

Description

technical field [0001] The invention relates to an oil drilling pipe forming die, in particular to an oil drilling pipe thickened end forming punch and its application. Background technique [0002] With the deepening of modern oil wells and water wells, the deterioration of the underground operating environment and the increase in the weight of the drill pipe itself, the performance requirements of the drill pipe are getting higher and higher, especially the performance of the transition zone at the thickened end of the drill pipe. At present, the upsetting process is mainly used to process oil drill pipes. When using this process, defects such as uneven wall thickness variation, rough surface, and wrinkles are prone to occur in the transition zone of the thickened end. Stress concentration is easy to occur here during work, resulting in Drill pipe breaks. [0003] Chinese patent CN101767173A discloses a drill pipe upsetting and thickening process. After the pipe end of th...

AI Technical Summary

Problems solved by technology

However, in the above-mentioned patents, since the punch is still a cylindrical structure, and the taper of the thickening die and the clamping die are small, there will still be defects such as uneven wall thickness variation, rough surface, and wrinkles in the transition zone.

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