阅读说明：本技术 一种930MPa级超高强度钛合金钻杆用管材及其制造方法 (Pipe for 930 MPa-level ultrahigh-strength titanium alloy drill rod and manufacturing method thereof ) 是由 冯春 蒋龙 李睿哲 陈长春 谢俊峰 冯耀荣 杨尚谕 于 2020-04-30 设计创作，主要内容包括：本发明公开了一种930MPa级超高强度钛合金钻杆用管材及其制造方法,属于石油天然气工业油井管制造技术领域。以质量百分比计,该钛合金管材的组成为Al：5.8～6.5％,V：2.0～3.0％,Zr：1.0～1.7％,Mo：0.5～1.0％,余量为Ti和不可避免的杂质。其制造方法是：冶炼、浇铸、锭坯锻造、挤压、轧制、退火处理、多级固溶处理、预拉伸处理和时效处理。通过本发明所述的制造方法得到的钛合金钻杆屈服强度大于930MPa,延伸率大于10％,满足API-5DP中135Ksi强度级别钻杆力学性能标准要求。(The invention discloses a pipe for a 930 MPa-level ultrahigh-strength titanium alloy drill rod and a manufacturing method thereof, belonging to the technical field of manufacturing of oil well pipes in the petroleum and gas industry. The titanium alloy pipe comprises the following components in percentage by mass: 5.8-6.5%, V: 2.0-3.0%, Zr: 1.0-1.7%, Mo: 0.5 to 1.0% and the balance of Ti and inevitable impurities. The manufacturing method comprises the following steps: smelting, casting, ingot blank forging, extruding, rolling, annealing treatment, multi-stage solution treatment, pre-stretching treatment and aging treatment. The titanium alloy drill rod obtained by the manufacturing method has yield strength of more than 930MPa and elongation of more than 10 percent, and meets the mechanical property standard requirement of 135Ksi strength level drill rods in API-5 DP.)

1. The pipe for the 930 MPa-level ultrahigh-strength titanium alloy drill pipe is characterized by comprising the following components in percentage by mass: al: 5.8% -6.5%, V: 2.0% -3.0%, Zr: 1.0% -1.7%, Mo: 0.5 to 1.0 percent, and the balance of Ti and inevitable impurities.

2. The pipe material for the 930 MPa-grade ultrahigh-strength titanium alloy drill rod as claimed in claim 1, wherein the tensile property of the pipe material is as follows: yield strength R_0.2Not less than 933MPa, tensile strength R_m1051MPa, elongation of 10% or more, and impact power A_KV≧60J。

3. A method for manufacturing the pipe material for the 930MPa grade ultra-high strength titanium alloy drill pipe according to claim 1 or 2, comprising the steps of:

1) weighing the raw materials according to the mass percentage, mixing the raw materials, and then smelting, casting and forging to prepare an ingot blank;

2) heating the ingot blank prepared in the step 1), and then extruding and rolling to form a pipe;

3) annealing the tube rolled in the step 2), then carrying out multi-stage solution treatment, namely, preserving heat for 2-3 h at 930-940 ℃, then preserving heat for 1.8-2.5 h at 910-920 ℃, firstly carrying out pre-stretching treatment with the tensile deformation of 1% -2% after air cooling, then carrying out artificial aging treatment, and finally carrying out air cooling to obtain the tube for the titanium alloy drill rod.

4. The manufacturing method of the tube for the 930 MPa-grade ultrahigh-strength titanium alloy drill rod according to claim 3, wherein the heating in the step 2) is to heat the ingot blank in the step 1) at 980-1050 ℃ for 0.8-1.2 h.

5. The manufacturing method of the tube for the 930 MPa-grade ultrahigh-strength titanium alloy drill rod according to claim 3, wherein in the extrusion process in the step 2), the extrusion parameters are set as follows: the extrusion ratio is 15-30, and the extrusion speed is 85-110 mm/s.

6. The manufacturing method of the tube for the 930 MPa-grade ultrahigh-strength titanium alloy drill rod as claimed in claim 3, wherein the rolling temperature in the step 2) is 450-500 ℃.

7. The manufacturing method of the tube for the 930 MPa-grade ultrahigh-strength titanium alloy drill rod as claimed in claim 3, wherein the annealing temperature in the step 3) is 850-950 ℃, and the annealing time is 1-1.5 h.

8. The manufacturing method of the tube for the 930 MPa-grade ultrahigh-strength titanium alloy drill rod as claimed in claim 3, wherein the artificial aging treatment in the step 3) is to keep the temperature of the tube at 450-550 ℃ for 2-2.5 h and cool the tube in air.

Technical Field

The invention belongs to the technical field of manufacturing of oil well pipes in the petroleum and gas industry, and relates to a pipe for a 930MPa ultrahigh-strength titanium alloy drill pipe and a manufacturing method thereof, which are suitable for a pipe body of a titanium alloy petroleum drill pipe.

Background

Currently, global oil and gas exploration and development are developing from conventional oil and gas reservoirs to low-pressure low-permeability unconventional directions, from land exploitation to ocean exploitation, and from shallow exploitation to deep and ultra-deep exploitation. Oil and gas resources to be developed are mainly concentrated in low-permeability, deep oil and gas reservoirs, ocean oil and gas reservoirs, unconventional oil and gas reservoirs and the like. At present, the deepest wells in the world can reach 12289m in the vertical direction, 11739m in the horizontal direction and 3400m in the deep water wells, and the increasing of unconventional oil and gas fields causes the drilling and production to be more and more difficult, such as the high temperature, high pressure and high Cl which are faced currently^-High content, high CO₂And H₂The working conditions such as S content, high erosion and the like are influenced by the harsh working conditions, environmental factors and the combined action of the harsh working conditions and the environmental factors, so that the failure accident of the petroleum pipe occurs. In order to meet the drilling requirements of wells with special working conditions at home and abroad, a series of light alloy drilling tools and equipment are developed, wherein an aluminum alloy drill rod is already used in the oil exploration and development industry, and a titanium alloy drill rod serving as a novel light drill rod also starts to be exposed at a head angle. The titanium alloy drill rod has the excellent characteristics of high specific strength, corrosion resistance, no magnetism and the like, and has good adaptability in drilling applications in deep well, ultra-deep well and deep sea drilling operation.

In the aspect of titanium alloy drill rod material design and preparation technology, the existing system theory research is less, and on the other hand, the problems of titanium alloy drill rod material deletion above an ultrahigh steel grade, low material toughness and the like exist in the research and development of the titanium alloy drill rod material.

In summary, there is a need to develop a titanium alloy pipe with low cost and high yield strength, so that the pipe can be used in deep wells under harsh working conditions, and failure accidents of petroleum pipes are avoided.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide a pipe for a 930 MPa-level ultrahigh-strength titanium alloy drill rod and a manufacturing method thereof, and solve the problem that the existing titanium alloy pipe fails to work in a deep well due to the fact that the yield strength is too low.

In order to achieve the purpose, the invention adopts the following technical scheme to realize the purpose:

the pipe for the 930 MPa-level ultrahigh-strength titanium alloy drill pipe comprises the following components in percentage by mass: al: 5.8% -6.5%, V: 2.0% -3.0%, Zr: 1.0% -1.7%, Mo: 0.5 to 1.0 percent, and the balance of Ti and inevitable impurities.

Preferably, the tensile properties of the pipe are: yield strength R_0.2Not less than 933MPa, tensile strength R_m1051MPa, elongation of 10% or more, and impact power A_KV≧60J。

A method for manufacturing a pipe for a 930 MPa-level ultrahigh-strength titanium alloy drill rod comprises the following steps:

1) weighing the raw materials according to the mass percentage, mixing the raw materials, and then smelting, casting and forging to prepare an ingot blank;

2) heating the ingot blank prepared in the step 1), and then extruding and rolling to form a pipe;

3) annealing the tube rolled in the step 2), then carrying out multi-stage solution treatment, namely, preserving heat for 2-3 h at 930-940 ℃, then preserving heat for 1.8-2.5 h at 910-920 ℃, firstly carrying out pre-stretching treatment with the tensile deformation of 1% -2% after air cooling, then carrying out artificial aging treatment, and finally carrying out air cooling to obtain the tube for the titanium alloy drill rod.

Preferably, the heating in the step 2) is to heat the ingot blank in the step 1) at 980-1050 ℃ for 0.8-1.2 h.

Preferably, in the extrusion process in step 2), the extrusion parameters are set as follows: the extrusion ratio is 15-30, and the extrusion speed is 85-110 mm/s.

Preferably, the rolling temperature in the step 2) is 450-500 ℃.

Preferably, the annealing temperature in the step 3) is 850-950 ℃, and the annealing time is 1-1.5 h.

Preferably, the artificial aging treatment in the step 3) is to keep the temperature of the pipe at 450-550 ℃ for 2-2.5 h, and air-cool the pipe.

Compared with the prior art, the invention has the following beneficial effects:

the invention discloses a pipe for a 930 MPa-level ultrahigh-strength titanium alloy drill rod, and the Al and V contents are controlled in the material formula of the pipe, so that the yield of the pipe can be increased. By utilizing the characteristics of solid solution strengthening of Al element and secondary alpha phase precipitation caused in the aging process, the content of Al in the titanium alloy is controlled, the alloy strength is fully improved, the addition of Zr and Mo elements has the effect of refining grains, and the yield strength of the alloy is further improved.

The invention also discloses a manufacturing method of the tube for the 930 MPa-level ultrahigh-strength titanium alloy drill rod, which adopts a heat treatment process of multi-stage solid solution treatment, pre-stretching treatment and artificial aging on the process, and obtains coarse crystal tissues, namely original beta crystal grains and lamellar alpha phases with larger sizes through extrusion rolling and air cooling after multi-stage solid solution treatment, thereby ensuring higher impact energy; by applying pre-stretching treatment with 1% -2% of stretching deformation, higher dislocation density is generated, fine and dispersed secondary alpha phase can be obtained by aging treatment, and the secondary alpha phase firstly nucleates and grows at the dislocation to generate a maximum phase interface, so that the interface strengthening effect is generated, and the sufficient yield strength is ensured; dislocation slip in the original beta grains can ensure sufficient elongation, so that the toughness is improved while the high strength of the titanium alloy pipe is maintained. The heat treatment stage of the existing titanium alloy pipe manufacturing method is directly solid solution treatment and aging treatment, and the difference of the process and the prior art is that: the solution treatment adopts double-stage secondary solution treatment, and proper pre-stretching treatment is supplemented after the solution treatment, so that the yield strength of the pipe is obviously improved.

The titanium alloy drill rod obtained by the process route has yield strength of more than 930MPa and elongation of more than 10 percent, and meets the mechanical property standard requirement of 135Ksi strength level drill rods in API-5 DP.

The performance of the titanium alloy drill rod produced according to the technical scheme of the invention can meet the following requirements:

(1) the tensile property of the pipe body is as follows: yield strength R_0.2Not less than 933MPa, tensile strength R_m1051MPa, elongation of 10% or more, and impact power A_KVNot less than 60J, and meets the mechanical property standard requirement of the 135Ksi strength level drill rod in API-5 DP;

(2) the microstructure of the tube body is large-grain equiaxial beta tissue, fine lamella secondary alpha phase and high dislocation density.

Drawings

FIG. 1 is a transmission electron microscope image of a titanium alloy tube prepared in example 1 of the present invention;

FIG. 2 is a transmission electron microscope image of a titanium alloy tube prepared in example 2 of the present invention;

FIG. 3 is a transmission electron microscope image of a titanium alloy tube manufactured in example 3 of the present invention;

FIG. 4 is a graph of the strength of titanium alloy tubing made according to 3 examples of the present invention;

FIG. 5 shows the elongation and the impact energy of the titanium alloy tube prepared according to 3 examples of the present invention.

Detailed Description

In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

The invention is described in further detail below with reference to the accompanying drawings:

in the existing titanium alloy material, Al is α phase stabilizing element, can improve the transformation point, can be greatly dissolved and expanded in the α phase α phase region, mainly plays a role of solid solution strengthening, and can increase the tensile strength of the titanium alloy material by 50MPa at room temperature but the Al content cannot be too high every 1 percent of Al is added, otherwise Ti can be formed₃The Al brittle phase can also increase the extrusion difficulty, Zr is a common neutral element, has higher solubility in α titanium and β titanium, is added with other elements at the same time, has a complementary strengthening effect, has less adverse effect on the plasticity of the alloy material than Al, ensures that the alloy has good pressure processing performance and welding performance, mainly plays roles of solid solution strengthening, aging strengthening and precipitation strengthening, and has the effect of refining crystal grains by proper amount of Zr, and V and Mo are two elements which are most widely applied in β stable elements, play a role of solid solution strengthening on β phase, reduce the phase transformation point, increase the hardenability of the alloy, so as to strengthen the heat treatment effect, but the V content is too high and easily increase the production cost.