One-step forming machining method for threaded single tool with double wiring pipes for connecting oil well pipes

Abstract

The invention provides a one-step forming machining method for a threaded single tool with double wiring pipes for connecting oil well pipes. The method includes that a component with threads to be machined is clamped on a jaw of a pipe thread machining machine tool and rotates along with a spindle of the machine tool; a threaded chasing tool is mounted on a toolbar of the machine tool and is provided with double teeth or teeth with the quantity integral multiples of two is axially and radially fed along with a tool table of the machine tool, and the moving track of the cutter is consistent with a taper line of the threads to be machined; and the axial feed of the machine tool is proper so that the tool is axially fed by a thread helical pitch when the spindle rotates for each circle, and two spiral lines of the threads to be machined are simultaneously cut by one-step feed. The one-step forming machining method has the advantages that the threads of the double wiring pipes can be efficiently machined on a common pipe thread machine tool or a numerical-control machine tool, and machining efficiency of the common pipe thread machine tool is more obviously improved. In addition, the dimension precision of thread machining is high, the quality of a surface is high, the threaded surface formed by the two spiral lines is in smooth transition, and sealing reliability of matching of threaded connection is guaranteed.

Description

technical field [0001] The invention relates to oil well pipe thread processing technology, in particular to a double-line pipe thread single-knife one-time forming processing method for oil well pipe connection. Background technique [0002] In the oil and gas drilling and production industry, the oil well pipe and related accessories as the main structure of the oil and gas well consist of a pipe string composed of many single pipes connected by threads. As the weakest link of the pipe string, the processing quality of the threaded joint is directly related to the construction and service safety of oil and gas wells. Even a problem with a threaded joint may cause immeasurable losses. [0003] The API (American Petroleum Institute) threads widely used in oilfields at home and abroad and the special buckle threads developed in the later stage are all single-thread tapered pipe threads with only one helix, and the processing technology is very mature. Since the double-thread...

AI Technical Summary

Problems solved by technology

[0007] To sum up, the existing technology of both ordinary machine tools and CNC machine tools adopts the method of forming two helixes at one time without simultaneous forming for double-start thread processing, which does not exist for the connection of two thread surfaces for ordinary bolts or transmission screw. It is feasible for multi-line threads with transition problems and without considering processing efficiency, but it is not allowed for oil well pipe threads that require tight interference fit

The reasons are as follows: First, the processing accuracy of the thread, especially the surface quality, is difficult to guarantee. The connection of the thread surface formed by two helical lines is difficult to achieve a smooth transition, and the thread surface is prone to quality defects such as small shoulders or scratches. , destroy the sealing performance of the thread fit, and in severe cases, it will cause adhesive damage on the thread fit surface, making the thread stick; second, for multi-line threads with large pitch, deep tooth shape, and multiple cuttings to complete the processing, The multiple manual adjustments of ordinary machine tools will become too cumbersome, and the processing efficiency is very low. Even CNC machine tools cannot meet the production requirements of oil well pipes in large quantities and high efficiency.

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