Bimetal composite drill pipe body as well as preparation method and application thereof

Abstract

The invention discloses a bimetal composite drill pipe body and a preparation method and application thereof, and belongs to the technical field of metallurgical metal pipes. The inner-layer metal tube blank and the outer-layer metal tube blank of the double-metal composite drill rod tube body are made of the same metal, and the double-metal composite drill rod tube body is prepared through the steps of hot charging, seal welding, multi-pass crossed hot strong spinning, stress relief annealing and the like. Compared with a traditional single thermal compounding or mechanical compounding mode, a multi-pass crossed thermal strong spinning mode is adopted, the interface is subjected to three-way pressure stress during spinning, and meanwhile, under the combined action of spinning and heating, the high-strength, reliable and defect-free metallurgical bonding interface is achieved. The composite interface of the prepared bimetallic titanium alloy drill rod pipe body is metallurgically bonded, and the interface is reliable and free of defects; and the inner layer is made of near-alpha titanium alloy with high corrosion resistance, and can be applied to a well requiring high corrosion resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgical metal pipes, and in particular relates to a bimetallic composite drill pipe body, a preparation method and application thereof. Background Art

[0002] Bimetallic composite pipe is a pipe made of two different metal materials through a special process. It is widely used in oil fields, chemical industry, electric power and other industrial fields. The basic principle of bimetallic composite steel pipe is that the outer base pipe is responsible for bearing pressure and rigid support of the pipe, and the inner lining pipe is responsible for corrosion resistance and wear resistance. At present, there are many methods for preparing bimetallic composite pipes. Bimetallic composite pipes prepared by traditional mechanical composite method have problems such as poor interface bonding performance, easy bulging and separation of the inner layer, collapse, cracking of the pipe end ring weld, etc., which pose safety hazards in actual use; bimetallic composite pipes prepared by centrifugal casting have inaccurate inner hole size and poor inner surface quality, which cannot meet the use requirements of oil pipelines, chemical industry and other fields; composite pipes prepared by explosive composite plate welding method have metallurgical bonding interface, but are prone to defects such as poor bonding and surface burns. In addition, the explosive composite method has a low degree of mechanization, which is not conducive to continuous production.

[0003] Patent CN 118492105 A adopts the method of hot-loading and hot-rolling to prepare bimetallic steel drill pipe body. However, the tube blank is subjected to axial tensile force during hot-rolling, which is not conducive to the formation of stable interface bonding. Therefore, it is of great significance to achieve a high-strength, reliable, and defect-free metallurgical bonding interface under the combined action of heat and mechanical forces, and to prepare a bimetallic composite drill pipe body with reliable interface formation. Summary of the invention

[0004] The present invention provides a bimetallic composite drill pipe body, wherein the inner metal tube blank and the outer metal tube blank are made of the same metal. Preferably, the outer metal tube blank is made of medium-high strength and high toughness titanium alloy, including but not limited to TA15, TC4, Ti80 and other titanium alloys; the inner metal tube blank is made of near-α-type titanium alloy with good corrosion resistance, including but not limited to TA5, TA9, TA18, TA16, Ti75, Ti31, Ti91, Ti70 and Ti80 and other titanium alloys.

[0005] The present invention provides a method for preparing the bimetallic composite drill pipe body, comprising the following steps:

[0006] (1) Thermal mounting and sealing

[0007] The inner metal tube blank and the outer metal tube blank are subjected to solution treatment respectively, and then the inner and outer metal tube blanks are assembled by hot-fitting; after the assembly is completed, the two ends of the composite tube are sealed and welded;

[0008] (2) Multi-pass cross-heat intense spinning

[0009] The assembled composite pipe is subjected to multiple cross-pass hot strong spinning; the first pass of hot strong spinning is counter-rotation, and the rotation direction of the mandrel is opposite to that of the rotating wheel; the second pass of hot strong spinning is counter-rotation, and the rotation direction of the mandrel is opposite to that of the first pass, and the rotation direction of the rotating wheel remains unchanged;

[0010] (3) Stress relief annealing

[0011] The bimetallic composite pipe prepared by cross hot spinning is subjected to simple stress relief annealing to obtain a finished pipe, namely a bimetallic composite drill pipe body.

[0012] In the above preparation method, in step (1), the solution treatment conditions are selected from: β Keep warm at -(30~50)℃ for 1~3h.

[0013] In the above preparation method, in step (1), the assembly conditions are selected from: reheating the outer metal tube after solution treatment to 500-600°C and assembling it with the cold inner tube of the core.

[0014] In the above preparation method, in step (1), the sealing welding is selected from the following conditions: the assembled pipe is placed in a vacuum electron beam welding machine for vacuum electron beam sealing welding at both ends, and the vacuum degree during welding is less than 1×10 -2 Pa.

[0015] In the above preparation method, in step (2), the wall thickness reduction rate of the first hot-spinning tube blank is 15-45%, the blank heating temperature is 700-800°C, the spinning wheel feed rate is 1.0-2.5 mm / r, and the spinning wheel speed is 100-150 r / min.

[0016] In the above preparation method, in step (2), the wall thickness reduction rate of the second hot-spinning tube blank is 3-15%, the blank heating temperature is 600-700°C; the wheel feed rate is 1.0-2.0 mm / r, and the wheel speed is 100-130 r / min.

[0017] In the above preparation method, in the step (3), the temperature of the stress relief annealing is selected from 500 to 600°C.

[0018] The present invention provides application of the bimetallic composite drill pipe body in a well with a highly corrosive medium environment.

[0019] In the present invention, the bimetallic composite drill pipe body can be used as a drill pipe body or a joint, and its outer surface is wear-resistant and its inner surface is corrosion-resistant.

[0020] The beneficial effects of the present invention are:

[0021] Compared with the traditional single thermal composite or mechanical composite method, the present invention adopts a multi-pass cross-heat strong spinning method. During spinning, the interface is subjected to three-dimensional compressive stress. At the same time, under the combined action of spinning and heating, a high-strength, reliable, and defect-free metallurgical bonding interface is achieved. The prepared bimetallic titanium alloy drill pipe body composite interface is metallurgical bonding, and the interface is reliable and defect-free; the inner layer uses a near-α titanium alloy with high corrosion resistance, which can be used underground where high corrosion resistance is required. DETAILED DESCRIPTION

[0022] Other materials used in the present invention, if not otherwise stated, can be obtained through commercial channels. Other terms used in the present invention, unless otherwise specified, generally have the meanings commonly understood by those of ordinary skill in the art. The present invention is further described in detail below in conjunction with specific examples and with reference to data. The following examples are only for illustrating the present invention, and are not intended to limit the scope of the present invention in any way.

[0023] Example 1

[0024] The steps for preparing bimetallic composite drill pipe are as follows:

[0025] The outer tube is TA15 titanium alloy with specifications of Ф135.5*Ф115.5*600mm; the inner tube is TC16 titanium alloy with specifications of Ф115.5*Ф95.5*600mm.

[0026] (1) Thermal mounting and sealing

[0027] The outer tube was kept at 980℃ for 1h for solution treatment and air-cooled; the inner tube was kept at 810℃ for 1h for solution treatment and air-cooled; the outer tube after solution treatment was reheated to 550℃ and assembled with the cold inner tube of the core; after cooling, the two formed an interference fit; the hot-fitted tube was placed in a vacuum electron beam welding machine for vacuum electron beam sealing welding at both ends, and the vacuum degree during welding was less than 1×10 -2 Pa, a mechanically composite bimetallic tube is obtained;

[0028] (2) Multi-pass cross-heat intense spinning

[0029] Hot spinning of bimetallic tubes; the outer diameter of the spinning mandrel is 95mm, and lubricating liquid is applied to the mandrel and the inner surface of the tube before spinning; the spinning wheel and the mandrel move in opposite directions; the first spinning wheel feed is 2.1mm / r, and the spinning wheel speed is 130r / min; the blank is heated by a flame heating chamber during the spinning process to ensure that the blank temperature is 800℃ during the spinning process;

[0030] The wall thickness reduction rate of the first pass is 30%, and the wall thickness reduction is 6mm; the inner and outer surfaces of the tube blank after the first pass of spinning are polished and then coated with lubricating liquid for the second pass of hot spinning;

[0031] The mandrel rotation direction of the second hot spinning pass is opposite to that of the first pass, and the spinning wheel direction remains unchanged; the spinning wheel feed is 2.0mm / r, and the spinning wheel speed is 100r / min; the blank temperature is maintained at 700℃; the wall thickness thinning rate of the second pass is 15%, and the thinning amount is 2mm;

[0032] (3) Stress relief annealing

[0033] The bimetallic composite pipe prepared by cross spinning is then subjected to simple stress relief annealing at a temperature of 600° C. to obtain a finished pipe, namely a bimetallic composite drill pipe.

[0034] In the present invention, a mechanically assembled bimetallic tube is formed by hot-fitting after solid solution and vacuum sealing. The purpose of this processing flow is that both titanium tubes are in a solid solution state, with low strength, good plasticity, and good processing and forming properties, which is conducive to subsequent spinning. On the one hand, cross-spinning can make the deformation of the organization more uniform and reduce the anisotropy of the performance; on the other hand, the interface bonding is more complete after cross-spinning; and when multiple passes of non-cross-spinning are performed, the tube blank organization will form an obvious orientation along the axial direction, resulting in various differences in transverse and longitudinal mechanical properties. Through simple heat treatment, the interface that has undergone mechanical deformation forms a reliable bond under the action of element diffusion, which is conducive to improving the interface bonding strength.

[0035] Compared with pipes prepared by traditional methods, such as mechanical composite-solid solution aging heat treatment and explosive composite-solid solution aging heat treatment, the solid solution (reducing heat working resistance)-hot spinning-simple stress relief annealing (improving interface strength and pipe strength) method adopted in the present invention has a simpler heat treatment system. Under the combined thermal and mechanical effects of spinning heating and spinning pressure, the composite pipe body interface can achieve good metallurgical bonding.

[0036] The above is only a preferred embodiment of the present invention, and does not limit the present invention in other forms. Any technician familiar with the profession may use the above disclosed technical content to change or modify it into an equivalent embodiment with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the technical solution of the present invention still belongs to the protection scope of the technical solution of the present invention.

Claims

1. A bimetallic composite drill pipe body, characterized in that: The inner metal tube blank and the outer metal tube blank are made of the same metal; the outer metal tube blank is made of medium-high strength and high toughness titanium alloy, and the inner metal tube blank is made of corrosion-resistant near-α-type titanium alloy.

2. The bimetallic composite drill pipe body according to claim 1, characterized in that: The outer metal tube blank is selected from one of TA15, TC4, and Ti80 titanium alloys; the inner metal tube is selected from one of TA5, TA9, TA18, TA16, Ti75, Ti31, Ti91, Ti70, and Ti80 titanium alloys.

3. The method for preparing the bimetallic composite drill pipe body according to claim 1, characterized in that: The steps include: (1) Thermal mounting and sealing The inner metal tube blank and the outer metal tube blank are subjected to solution treatment respectively, and then the inner and outer metal tube blanks are assembled by hot-fitting; after the assembly is completed, the two ends of the composite tube are sealed and welded; (2) Multi-pass cross-heat intense spinning The assembled composite pipe is subjected to multiple cross-pass hot strong spinning; the first pass of hot strong spinning is counter-rotation, and the rotation direction of the mandrel is opposite to that of the rotating wheel; the second pass of hot strong spinning is counter-rotation, and the rotation direction of the mandrel is opposite to that of the first pass, and the rotation direction of the rotating wheel remains unchanged; (3) Stress relief annealing The bimetallic composite pipe prepared by cross hot spinning is subjected to simple stress relief annealing to obtain a finished pipe, namely a bimetallic composite drill pipe body.

4. The preparation method according to claim 3, characterized in that: In the step (1), the solution treatment conditions are selected from: β Keep warm at -(30~50)℃ for 1~3h.

5. The preparation method according to claim 3, characterized in that: In the step (1), the assembly conditions are selected from: reheating the outer metal tube after the solution treatment to 500-600° C. and assembling it with the cold inner tube of the core.

6. The preparation method according to claim 3, characterized in that: In the step (1), the sealing welding is selected from the following conditions: the assembled pipe is placed in a vacuum electron beam welding machine for vacuum electron beam sealing welding at both ends, and the vacuum degree during welding is less than 1×10 -2 Pa.

7. The preparation method according to claim 3, characterized in that: In the step (2), the wall thickness reduction rate of the first heat-spinning tube blank is 15-45%, the blank heating temperature is 700-800°C, the spinning wheel feed rate is 1.0-2.5 mm / r, and the spinning wheel speed is 100-150 r / min.

8. The preparation method according to claim 3, characterized in that: In the step (2), the wall thickness reduction rate of the second hot-spinning tube blank is 3-15%, the blank heating temperature is 600-700°C; the spinning wheel feed rate is 1.0-2.0 mm / r, and the spinning wheel speed is 100-130 r / min.

9. The preparation method according to claim 3, characterized in that: In the step (3), the temperature of the stress relief annealing is selected from 500 to 600°C.

10. Use of the bimetallic composite drill pipe body according to claim 1 in a well with a highly corrosive medium environment.