Manufacturing method of oil casing coupling blank

Abstract

The invention discloses a manufacturing method of an oil casing coupling blank. The manufacturing method of the oil casing coupling blank comprises the steps that a seamless steel pipe is placed in anextruding mould provided with a cylindrical inner cavity; and a pair of pressure heads is correspondingly used for opposite-direction extruding feeding in the axial direction of the seamless steel pipe from the interiors of the two ends of the axial direction of the seamless steel pipe, so that two coupling blank connecting parts having the conicity, and a boss which is arranged between the two coupling blank connecting parts are formed on the inner wall of the seamless steel pipe. According to the manufacturing method of the oil casing coupling blank, the machining efficiency of the couplingblank can be improved, the metal yield of the coupling blank is raised, the mechanical property of the coupling blank can be improved, and the manufacturing method of the oil casing coupling blank iswidely suitable for the field of oil well pipes, pipeline pipes, drilling pipes and the like which require coupling connection.

Description

technical field [0001] The invention relates to a manufacturing method, in particular to a manufacturing method of an oil casing collar blank. Background technique [0002] The oil and casing pipe string is usually connected by thread, and the connection form is pipe body-coupling-pipe body, and the coupling is in the form of internal threads at both ends. In the prior art, the usual production method of the coupling blank is turning. However, because the thread of the finished coupling usually has a certain degree of taper, and some threads (such as air-tight threads) will have a raised shoulder part in the middle, so what is required for machining the coupling blank by turning The wall thickness of the turned pipe is usually relatively thick, and the finished product of the coupling needs to be turned to remove a lot of material, which leads to difficulties in processing the blank of the coupling and low efficiency; on the other hand, the metal yield of the finished coupl...

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Problems solved by technology

However, because the thread of the finished coupling usually has a certain degree of taper, and some threads (such as air-tight threads) will have a raised shoulder part in the middle, so what is required for machining the coupling blank by turning The wall thickness of the turned pipe is usually relatively thick, and the finished product of the coupling needs to be turned to remove a lot of material, which leads to difficulties in processing the blank of the coupling and low efficiency; on the other hand, the metal yield of the finished coupling is low (The recovery rate of the finished metal of some threaded couplings is less than 50%), resulting in huge waste

[0003] In addition, in the prior art, in the process of turning the pipe into a coupling blank, due to the thick wall thickness of the required pipe, it will make it difficult to roll the pipe, resulting in various rolling defects

In addition, during the turning process, due to the small amount of deformation of the pipe material, the microscopic grains of the coupling blank are thicker than the pipe body, so that the mechanical properties of the coupling blank are often worse than the pipe body, which brings certain problems to the use of the coupling blank. risks of

[0004] In the prior art, the publication number is CN101829679A, the publication date is September 15, 2010, and the Chinese patent document titled "A Production Method for Improving the Impact Toughness of Hot-rolled Oil Well Pipe Coupling Material" discloses a method for improving hot-rolled oil well pipe coupling materials. The core of the production method of impact toughness of oil well pipe coupling materials is two-stage cooling after rolling in order to improve the structure and performance, but the main manufacturing process is still the traditional rolling process

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