Ga-Si-containing sealing copper alloy and preparation method and application thereof

Abstract

The invention relates to a sealing copper alloy containing Ga-Si as well as a preparation method and application of the sealing copper alloy. The sealing copper alloy containing Ga-Si comprises the following components in percentage by mass: 3.0 to 12.0 weight percent of Ga, 1.0 to 3.0 weight percent of Si, 0.04 to 0.09 weight percent of Ag, 0.6 to 4.7 weight percent of Ni and the balance of Cu. According to the copper alloy, the formula of the copper alloy is adjusted, the sealing performance of the alloy is improved by means of Ga and Si, the sealing temperature of the copper alloy can reach 300 DEG C, the working temperature of the sealing copper alloy is 100 DEG C higher than that of a red copper material used for sealing at present, and the sealing copper alloy can meet the requirements of underground sealing parts. Therefore, the long-term sealing performance of the sealing element in the high-temperature and high-pressure environment is guaranteed, and the problems that rubber sealing element materials such as hangers and packers in the deep well and the ultra-deep well in the high-temperature, high-pressure and corrosive medium environment are prone to failure and aging, and good sealing performance is difficult to maintain are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of copper alloy materials, and particularly relates to a Ga-Si-containing sealing copper alloy and its preparation method and use. Background Art

[0002] At present, in the oil drilling industry, deep well pipes usually need to be leak repaired within a certain range according to different downhole actions. The common leak repair method is to use the expandable pipe technology, and a rubber seal is used for sealing between the expandable pipe and the original pipe. Due to the advantages of good sealing performance, low expansion pressure, simple operation, high reliability, etc. of the rubber seal, it has been widely used in the drilling industry.

[0003] For example, CN115450901A discloses an oilfield drilling rubber seal and its preparation method, including a fixing ring, multiple through grooves are opened on the fixing ring, multiple grooves are opened in each of the multiple through grooves, a spring for rebounding is fixedly connected in each of the multiple grooves, a sliding rod is slidably connected in each of the multiple grooves, two limiting wheels for limiting are rotatably connected to each of the multiple sliding rods, a fixing block for supporting the movement of the sliding rod is fixedly connected to each of the multiple sliding pipes, the multiple springs are respectively fixedly connected to the multiple fixing blocks, rubber gaskets for sealing are arranged at both the upper and lower ends of the fixing ring, multiple connecting blocks are fixedly connected to each of the two rubber gaskets, and multiple limiting grooves for pressing against the limiting wheels are opened on each of the multiple connecting blocks.

[0004] However, due to the limitation of the heat resistance of the rubber material, its maximum working temperature ≤ 140°C. At the same time, with the continuous development of deep well drilling technology, the drilling depth is increasing, and the working temperature that the expandable pipe needs to face has reached 300°C or even higher, making the existing expandable pipe rubber sealing materials unusable. In addition, with the improvement of the design life (≥ 20 years) of deep well expandable pipes, it greatly exceeds the service limit of the existing rubber sealing materials.

[0005] Metal sealing materials, with their characteristics of high working temperature and long service life, have become the most potential sealing material to meet the above requirements. Currently available metal sealing materials include Cu, Ag, In, stainless steel, and superalloys, etc. Among them, Ag and In alloys are relatively soft, have good sealing performance, but have insufficient strength, low use temperature, and high cost; stainless steel and superalloys have a relatively high use temperature and can meet high-temperature sealing, but due to their hard texture, high expansion pressure, and small sealing interference, their sealing performance is poor.

[0006] Copper alloys have a certain strength and good plasticity and toughness, and are often used as sealing gaskets. However, copper alloy gaskets still have the following disadvantages:

[0007] (1) Insufficient plasticity and viscosity, and the sealing performance is inferior to that of Ag and In alloys;

[0008] (2) The sealing temperature of the copper alloy is relatively low, only 200 °C.

[0009] It can be known that there are problems of insufficient plasticity and viscosity and relatively low sealing temperature when the copper alloy is used as a sealing gasket. Summary of the Invention

[0010] In view of the problems existing in the prior art, the purpose of the present invention is to provide a Ga-Si-containing sealed copper alloy, its preparation method and use, so as to solve the problems of insufficient plasticity and viscosity and relatively low sealing temperature when the copper alloy is used as a sealing gasket. The sealing temperature of the obtained Ga-Si sealed copper alloy can reach above 300 °C, and the sealing performance is better than that of the existing copper gasket materials, which can meet the requirements of downhole seals.

[0011] To achieve this purpose, the present invention adopts the following technical solutions:

[0012] In the first aspect, the present invention provides a Ga-Si-containing sealed copper alloy, and the Ga-Si-containing sealed copper alloy includes, by mass percentage:

[0013] Ga 3.0 - 12.0 wt%, Si 1.0 - 3.0 wt%, Ag 0.04 - 0.09 wt%, Ni 0.6 - 4.7 wt%, and the balance is Cu.

[0014] The copper alloy provided by the present invention develops a sealed copper alloy with a sealing temperature of up to 300 °C that can meet the requirements of downhole seals by adjusting the copper alloy formula and increasing the alloy sealing performance with the help of Ga and Si, thereby ensuring the long-term sealing performance of the sealing element in high-temperature and high-pressure environments. It has a working temperature 100 °C higher than that of the current T1 oxygen-free copper material used for sealing, and solves the problems that rubber sealing element materials such as hangers and packers are prone to failure and aging and difficult to maintain good sealing performance in high-temperature, high-pressure and corrosive medium environments in deep wells and ultra-deep wells.

[0015] As a preferred technical solution of the present invention, the Ga-Si-containing sealed copper alloy includes, by mass percentage: Ga 6 - 8 wt%, Si 2 - 2.2 wt%, Ag 0.06 - 0.07 wt%, Ni 2.5 - 2.7 wt%, and the balance is Cu.

[0016] In the second aspect, the present invention provides a preparation method of the Ga-Si-containing sealed copper alloy as described in the first aspect, and the preparation method includes:

[0017] Vacuum induction melting is carried out on the raw materials according to the formula, and then centrifugal casting is carried out to obtain the Ga-Si-containing sealed copper alloy.

[0018] As a preferred technical solution of the present invention, vacuum pumping is carried out at the beginning of the vacuum induction melting.

[0019] Preferably, the absolute vacuum degree at the end point of vacuum pumping is 0.005 - 0.1 Pa.

[0020] As a preferred technical solution of the present invention, the operating temperature of the vacuum induction melting is 1400 - 1600 °C.

[0021] Preferably, the heating rate of the vacuum induction melting is 20 - 50 °C / s.

[0022] As a preferred technical solution of the present invention, the holding time of the vacuum induction melting is 0.5 - 1 h.

[0023] As a preferred technical solution of the present invention, the absolute vacuum degree of the centrifugal casting is 0.005 - 0.1 Pa.

[0024] As a preferred technical solution of the present invention, the rotational speed of the centrifuge in the centrifugal casting is 400 - 500 r / min.

[0025] In a third aspect, the present invention provides the use of the Ga-Si-containing sealing copper alloy as described in the first aspect, and the use includes preparing a metal seal using the obtained Ga-Si-containing sealing copper alloy.

[0026] As a preferred technical solution of the present invention, the sealing temperature of the metal seal is ≥ 300 °C.

[0027] Compared with the prior art solutions, the present invention has the following beneficial effects:

[0028] The sealing copper alloy provided by the present invention increases the sealing performance of the copper alloy by introducing gallium and silicon, and develops a sealing copper alloy with a sealing temperature up to over 300 °C, which can ensure the long-term sealing performance of the sealing element under high temperature and high pressure environments, and the tensile strength at 300 °C is ≥ 180 MPa. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is the metallographic diagram of the sealing copper alloy ingot obtained in Example 1 of the present invention.

[0030] The present invention will be further described in detail below. However, the following examples are merely simple examples of the present invention and do not represent or limit the scope of the protection of the present invention. The scope of protection of the present invention shall be subject to the claims. DETAILED DESCRIPTION OF THE INVENTION

[0031] To better illustrate the present invention and facilitate understanding of the technical solutions of the present invention, the typical but non-limiting embodiments of the present invention are as follows:

[0032] This embodiment provides a Ga-Si-containing sealing copper alloy, and the Ga-Si-containing sealing copper alloy includes, by mass percentage:

[0033] Ga 3.0 - 12.0 wt%, Si 1.0 - 3.0 wt%, Ag 0.04 - 0.09 wt%, Ni 0.6 - 4.7 wt%, and the balance is Cu.

[0034] In the present invention, in the Ga-Si containing sealing copper alloy, the content of Ga is 3.0 - 12.0 wt% by mass percentage. For example, it can be 3.0 wt%, 4.0 wt%, 5.0 wt%, 6.0 wt%, 7.0 wt%, 8.0 wt%, 9.0 wt%, 10.0 wt%, 11.0 wt% or 12.0 wt%, etc., but is not limited to the listed values, and other unlisted values within this range also meet the requirements.

[0035] In the present invention, in the Ga-Si containing sealing copper alloy, the content of Si is 1.0 - 3.0 wt% by mass percentage. For example, it can be 1.0 wt%, 1.2 wt%, 1.4 wt%, 1.6 wt%, 1.8 wt%, 2 wt%, 2.2 wt%, 2.4 wt%, 2.6 wt%, 2.8 wt% or 3.0 wt%, etc., but is not limited to the listed values, and other unlisted values within this range also meet the requirements.

[0036] In the present invention, in the Ga-Si containing sealing copper alloy, the content of Ag is 0.04 - 0.09 wt% by mass percentage. For example, it can be 0.04 wt%, 0.045 wt%, 0.05 wt%, 0.055 wt%, 0.06 wt%, 0.065 wt%, 0.07 wt%, 0.075 wt%, 0.08 wt%, 0.085 wt% or 0.09 wt%, etc., but is not limited to the listed values, and other unlisted values within this range also meet the requirements.

[0037] In the present invention, in the Ga-Si containing sealing copper alloy, the content of Ni is 0.6 - 4.7 wt% by mass percentage. For example, it can be 0.6 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt% or 4.7 wt%, etc., but is not limited to the listed values, and other unlisted values within this range also meet the requirements.

[0038] Specifically, the Ga-Si containing sealing copper alloy includes by mass percentage: Ga 8 - 12 wt%, Si 2.5 - 3 wt%, Ag 0.08 - 0.09 wt%, Ni 4.5 - 4.7 wt%, and the balance is Cu.

[0039] Furthermore, the present invention provides a preparation method of the Ga-Si containing sealing copper alloy as described above, including:

[0040] According to the formula, the raw materials are vacuum induction melted and then centrifugally cast to obtain Ga-Si sealing copper alloy.

[0041] In the present invention, the raw materials used in the vacuum melting can be selected as single raw materials of corresponding elements, or can be selected as intermediate alloy raw materials of related elements, such as nickel-copper intermediate alloy, copper-silicon intermediate alloy, etc.

[0042] In the present invention, the raw materials should be selected as high as possible to avoid the adverse effects of impurities on the properties of the copper alloy.

[0043] For example, the purity of the Cu raw material is ≥99.5wt%, the purity of the Ga raw material is ≥99.9wt%, the purity of the Si raw material is ≥99.9wt%, the purity of the Ni raw material is ≥99.9wt%, and the purity of the Ag raw material is ≥99.0wt%.

[0044] In the present invention, the raw material can be selected as powder and / or block material.

[0045] In the present invention, the raw materials are subjected to impurity removal treatment before vacuum induction melting, such as pickling and alcohol washing, to avoid the influence of impurities on the surface of the raw materials on the properties of the obtained copper alloy.

[0046] Among them, the acid wash is to use 5-8% dilute sulfuric acid for cleaning, and the alcohol wash is to use methanol, ethanol or ethylene glycol and other alcohol reagents for cleaning.

[0047] In the present invention, due to the specificity of gallium, the present invention provides an exemplary weighing method as follows: put a Ga block into a plastic cup, then put the plastic cup into hot water to melt the Ga (melt in hot water), use a dropper to absorb it, drop it into a culture dish to weigh the required weight, and put it into a refrigerator to freeze and solidify after weighing.

[0048] In the present invention, the gallium material is placed at the top of the material during vacuum induction melting. This is because the melting point of gallium is only 29.76°C. During the melting process, the gallium material is placed at the top of the material to avoid sticking to the pan.

[0049] Specifically, vacuuming is performed at the beginning of the vacuum induction melting.

[0050] Specifically, the absolute vacuum degree at the end point of the vacuuming is 0.005-0.1Pa, for example, it can be 0.005Pa, 0.06Pa, 0.007Pa, 0.008Pa, 0.009Pa, 0.01Pa, 0.02Pa, 0.04Pa, 0.06Pa, 0.08Pa or 0.1Pa, etc., but is not limited to the listed values, and other values ​​not listed within the range also meet the requirements.

[0051] Specifically, the operating temperature of the vacuum induction melting is 1400 - 1600 °C. For example, it can be 1400 °C, 1420 °C, 1440 °C, 1460 °C, 1480 °C, 1500 °C, 1520 °C, 1540 °C, 1560 °C, 1580 °C or 1600 °C, etc. However, it is not limited to the listed values, and other unlisted values within this range also meet the requirements.

[0052] Specifically, the heating rate of the vacuum induction melting is 20 - 50 °C / s. For example, it can be 20 °C / s, 25 °C / s, 30 °C / s, 35 °C / s, 40 °C / s, 45 °C / s or 50 °C / s, etc. However, it is not limited to the listed values, and other unlisted values within this range also meet the requirements.

[0053] Specifically, the holding time of the vacuum induction melting is 0.5 - 1 h. For example, it can be 0.5 h, 0.6 h, 0.7 h, 0.8 h, 0.9 h or 1 h, etc. However, it is not limited to the listed values, and other unlisted values within this range also meet the requirements.

[0054] Specifically, the absolute vacuum degree of the centrifugal casting is 0.005 - 0.1 Pa. For example, it can be 0.005 Pa, 0.06 Pa, 0.007 Pa, 0.008 Pa, 0.009 Pa, 0.01 Pa, 0.02 Pa, 0.04 Pa, 0.06 Pa, 0.08 Pa or 0.1 Pa, etc. However, it is not limited to the listed values, and other unlisted values within this range also meet the requirements.

[0055] Specifically, the rotational speed of the centrifuge in the centrifugal casting is 400 - 500 r / min. For example, it can be 400 r / min, 420 r / min, 440 r / min, 460 r / min, 480 r / min or 500 r / min, etc. However, it is not limited to the listed values, and other unlisted values within this range also meet the requirements.

[0056] In the present invention, the cast body obtained by centrifugal casting is cooled with the furnace to room temperature, such as ≤40 °C.

[0057] Furthermore, in order to illustrate the excellent properties of the Ga-Si-containing sealing copper alloy provided by the present invention, the following specific examples are provided for description, as follows:

[0058] Example 1

[0059] This example provides a Ga-Si-containing sealing copper alloy ingot with a total weight of 200 g, which is composed of alloy components with the following mass percentages: 3.0 wt.% of Ga, 1.0 wt.% of Si, 0.04 wt.% of Ag, 0.6 wt.% of Ni, and the balance is Cu.

[0060] Cut the Cu block into pieces of 2 cm in size, weigh 190.72 g, then put it into a 5% dilute sulfuric acid solution for pickling, and then ultrasonically clean the pickled Cu block with alcohol 4 times and store it in a sealed manner; similarly, weigh 1.2 g of Ni block and 0.08 g of Ag, pickle them and then ultrasonically clean them with alcohol and store them in a sealed manner; weigh Ga as follows: put the Ga block into a plastic cup, and then put the plastic cup into hot water to melt Ga (melt it through hot water), suck it with a dropper, drop it into a petri dish and weigh 6 g, and put it into the refrigerator to freeze and solidify after weighing; weigh 2 g of Si powder, and vacuum arc refine the weighed Si powder and Cu into a Cu-Si master alloy;

[0061] Then put the above weighed raw materials into a graphite crucible and place it in a vacuum centrifugal casting furnace. Among them, the Cu, Cu-Si master alloy, Ni block and Ag block are evenly mixed and placed at the bottom layer, and the Ga block is placed on the top layer of the raw materials to be melted; evacuate the vacuum centrifugal casting furnace to 1×10 -1 Pa, heat it to 1400 °C at a heating rate of 20 °C / s and hold for 0.5 hours for vacuum induction melting, then keep the vacuum degree unchanged, cool the furnace to room temperature to complete centrifugal casting, and the rotation speed of the centrifuge during casting is 400 r / min, and finally obtain a sealed copper alloy ingot containing Ga-Si.

[0062] The metallographic diagram of the obtained sealed copper alloy ingot is as Figure 1 shown. It can be seen from the figure that the microstructure of the obtained sealed copper alloy ingot is equiaxed crystal, and no second phase is formed. The grain size of the obtained sealed copper alloy ingot is smaller than that of pure copper.

[0063] After testing, the tensile strength of the obtained Ga-Si sealed alloy at 300 °C is 203 MPa. Compared with the current T1 purple copper material used for sealing (the tensile strength at 200 °C is 160 MPa), it can still work at 300 °C under the premise of equivalent sealing performance.

[0064] Example 2

[0065] This example provides a sealed copper alloy ingot containing Ga-Si, with a total weight of 200 g, and is composed of alloy components with the following mass percentages: 3.0 wt.% of Ga, 3.0 wt.% of Si, 0.04 wt.% of Ag, 0.6 wt.% of Ni, and the balance is Cu.

[0066] The preparation method of the sealed copper alloy ingot containing Ga-Si in this example is as follows:

[0067] Cut the Cu block into pieces with a size of 3 cm, weigh 186.72 g, then put it into a 5% dilute sulfuric acid solution for pickling, and then ultrasonically clean the pickled Cu block with alcohol 4 times and store it in a sealed manner; similarly, weigh 1.2 g of Ni block and 0.08 g of Ag, pickle them and then ultrasonically clean them with alcohol and store them in a sealed manner; the weighing of Ga is as follows: put the Ga block into a plastic cup, and then put the plastic cup into hot water to melt Ga (melt it through hot water), suck it with a dropper, drop it into a petri dish and weigh 6 g, and then put it into the refrigerator to freeze and solidify after weighing; weigh 6 g of Si, and vacuum arc melt the weighed Si and Cu into an intermediate alloy;

[0068] Then put the above-mentioned weighed raw materials into a graphite crucible and place it in a vacuum centrifugal casting furnace. Among them, the Cu, Cu-Si intermediate alloy, Ni block and Ag block are evenly mixed and placed on the bottom layer, and the Ga block is placed on the top layer of the raw materials to be melted; evacuate the vacuum centrifugal casting furnace to 1×10 -1 Pa, heat it to 1400 °C at a heating rate of 20 °C / s and hold it for 0.5 hours for vacuum induction melting, then keep the vacuum degree unchanged, cool it to room temperature in the furnace to complete centrifugal casting, and the rotation speed of the centrifuge during casting is 400 r / min, and finally obtain a sealed copper alloy ingot containing Ga-Si.

[0069] After testing, the tensile strength of the obtained sealed alloy containing Ga-Si is 188 MPa at 300 °C. Compared with the current T1 red copper material used for sealing (the tensile strength at 200 °C is 160 MPa), it can still work at 300 °C under the premise of equivalent sealing performance.

[0070] Example 3

[0071] This example provides a sealed copper alloy ingot containing Ga-Si with a total weight of 200 g, which is composed of alloy components with the following mass percentages: 12.0 wt.% of Ga, 1.0 wt.% of Si, 0.04 wt.% of Ag, 0.6 wt.% of Ni, and the balance is Cu.

[0072] The preparation method of the sealed copper alloy ingot containing Ga in this example is as follows:

[0073] Cut the Cu block into pieces with a size of 2 cm, weigh 172.72 g, then put it into a 5% dilute sulfuric acid solution for pickling, and then ultrasonically clean the pickled Cu block with alcohol 4 times and store it in a sealed manner; similarly, weigh 1.2 g of Ni block and 0.08 g of Ag, pickle them and then ultrasonically clean them with alcohol and store them in a sealed manner; the weighing of Ga is as follows: put the Ga block into a plastic cup, and then put the plastic cup into hot water to melt Ga (melt it through hot water), suck it with a dropper, drop it into a petri dish and weigh 24 g, and then put it into the refrigerator to freeze and solidify after weighing; weigh 2 g of Si, and vacuum arc smelt the weighed Si and Cu into an intermediate alloy;

[0074] Then put the above-mentioned weighed raw materials into a graphite crucible and place it in a vacuum centrifugal casting furnace. Among them, the Cu, Cu-Si intermediate alloy, Ni block and Ag block are evenly mixed and placed on the bottom layer, and the Ga block is placed on the top layer of the raw materials to be melted; evacuate the vacuum centrifugal casting furnace to 5×10 -3 Pa, heat it to 1400 °C at a heating rate of 50 °C / s and keep it warm for 0.5 hours for vacuum induction melting, and then keep the vacuum degree unchanged, cool it to room temperature in the furnace to complete centrifugal casting. The rotation speed of the centrifuge during casting is 400 r / min, and finally a sealed copper alloy ingot containing Ga-Si is obtained.

[0075] After testing, the tensile strength of the obtained Ga-Si sealed alloy at 300 °C is 180 MPa. Compared with the current T1 purple copper material used for sealing (the tensile strength at 200 °C is 160 MPa), it can still work up to 300 °C under the premise of equivalent sealing performance.

[0076] Example 4

[0077] This example provides a sealed copper alloy ingot containing Ga-Si with a total weight of 200 g, which is composed of alloy components with the following mass percentages: 12.0 wt.% of Ga, 3.0 wt.% of Si, 0.04 wt.% of Ag, 0.6 wt.% of Ni, and the rest is Cu.

[0078] The preparation method of the sealed copper alloy ingot containing Ga-Si in this example is as follows:

[0079] Cut the Cu block into pieces with a size of 3 cm, weigh 168.72 g, then put it into a 5% dilute sulfuric acid solution for pickling, and then ultrasonically clean the pickled Cu block with alcohol three times and store it in a sealed manner; similarly, weigh 1.2 g of Ni block and 0.08 g of Ag, pickle them and then ultrasonically clean them with alcohol and store them in a sealed manner; weigh Ga as follows: put the Ga block into a plastic cup, and then put the plastic cup into hot water to melt Ga (melt it through hot water), suck it with a dropper, drop it into a petri dish and weigh 24 g, and then put it into the refrigerator to freeze and solidify after weighing; weigh 6 g of Si, and vacuum arc smelt the weighed Si and Cu into an intermediate alloy;

[0080] Then put the above-mentioned weighed raw materials into a graphite crucible and place it in a vacuum centrifugal casting furnace. Among them, evenly mix the Cu, Cu-Si intermediate alloy, Ni block and Ag block and place them on the bottom layer, and then place the Ga block on the top layer of the raw materials to be smelted; evacuate the vacuum centrifugal casting furnace to 5×10 -3 Pa, heat it to 1400 °C at a heating rate of 50 °C / s and hold it for 0.5 hours for vacuum induction melting, then keep the vacuum degree unchanged, cool it to room temperature in the furnace to complete centrifugal casting, and the rotation speed of the centrifuge during casting is 500 r / min, and finally obtain a sealed copper alloy ingot containing Ga-Si.

[0081] After testing, the tensile strength of the obtained Ga-Si sealed alloy at 300 °C is 230 MPa. Compared with the current T1 pure copper material used for sealing (the tensile strength at 200 °C is 160 MPa), it can still work at 300 °C under the premise of equivalent sealing performance.

[0082] Example 5

[0083] This example provides a sealed copper alloy ingot containing Ga-Si, and the total weight of the ingot is 200 g, and the alloy composition is composed of the following mass percentages: 12 wt.% of Ga, 3.0 wt.% of Si, 0.09 wt.% of Ag, 4.7 wt.% of Ni, and the rest is Cu.

[0084] The preparation method of the sealed copper alloy ingot containing Ga-Si in this example is as follows:

[0085] Cut the Cu block into pieces of 2 cm in size, weigh 160.42 g, then put it into a 5% dilute sulfuric acid solution for pickling, and then ultrasonically clean the pickled Cu block with alcohol 4 times and store it in a sealed manner; similarly, weigh 9.4 g of Ni block and 0.18 g of Ag, pickle them and then ultrasonically clean them with alcohol and store them in a sealed manner; the weighing of Ga is as follows: put the Ga block into a plastic cup, and then put the plastic cup into hot water to melt Ga (melt it through hot water), suck it with a dropper, drop it into a petri dish and weigh 24 g, and after weighing, put it into the refrigerator to freeze and solidify; weigh 6 g of Si, and vacuum arc melt the weighed Si and Cu into an intermediate alloy;

[0086] Then put the above-mentioned weighed raw materials into a graphite crucible and place it in a vacuum centrifugal casting furnace. Among them, evenly mix the Cu, Cu-Si intermediate alloy, Ni block and Ag block and place them on the bottom layer, and place the Ga block on the top layer of the raw materials to be melted; evacuate the vacuum centrifugal casting furnace to 5×10 -3 Pa, heat it to 1400 °C at a heating rate of 20 °C / s and keep it warm for 0.5 hours for vacuum induction melting, then keep the vacuum degree unchanged, cool the furnace to room temperature to complete centrifugal casting, and the rotation speed of the centrifuge during casting is 500 r / min, and finally obtain a sealed copper alloy ingot containing Ga-Si.

[0087] After testing, the tensile strength of the obtained Ga-Si sealed alloy at 300 °C is 238 MPa. Compared with the current T1 purple copper material used for sealing (the tensile strength at 200 °C is 160 MPa), it can still work up to 300 °C under the premise of equivalent sealing performance.

[0088] From the results of the above embodiments, it can be seen that the copper alloy provided by the present invention, through the adjustment of the copper alloy formula, increases the sealing performance of the alloy by means of Ga and Si, and develops a sealed copper alloy with a sealing temperature up to 300 °C, which is 100 °C higher than the working temperature of the current T1 purple copper material used for sealing, and can meet the requirements of downhole seals, thus ensuring the long-term sealing performance of the sealing elements in high-temperature and high-pressure environments, and solving the problems that rubber sealing elements such as hangers and packers are prone to failure and aging and difficult to maintain good sealing performance in high-temperature, high-pressure and corrosive medium environments in deep wells and ultra-deep wells.

[0089] It is stated that the present invention uses the above embodiments to illustrate the detailed structural features of the present invention, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must rely on the above detailed structural features to be implemented. Those skilled in the art should understand that any improvement of the present invention, the equivalent replacement of the components selected by the present invention, the addition of auxiliary components, and the selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0090] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0091] In addition, it should be noted that, in the various specific technical features described in the above specific embodiments, they can be combined in any appropriate manner without contradiction. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

[0092] Furthermore, any combination can be made between various different embodiments of the present invention, as long as it does not violate the idea of the present invention, and it should also be regarded as the content disclosed by the present invention.

Claims

1. A Ga-Si containing sealing copper alloy, characterized in that: The Ga-Si sealing copper alloy comprises, by mass percentage: Ga 3.0-12.0wt%, Si 1.0-3.0wt%, Ag 0.04-0.09wt%, Ni 0.6-4.7wt%, and the balance is Cu.

2. The Ga-Si containing sealing copper alloy as claimed in claim 1, characterized in that: The Ga-Si sealing copper alloy comprises, in terms of mass percentage, 6-8wt% of Ga, 2-2.2wt% of Si, 0.06-0.07wt% of Ag, 2.5-2.7wt% of Ni, and the balance is Cu.

3. A method for preparing a Ga-Si-containing sealing copper alloy as claimed in claim 1 or 2, characterized in that: The preparation method comprises: The raw materials are vacuum induction melted according to the formula, and then centrifugal casting is performed to obtain the Ga-Si sealing copper alloy.

4. The preparation method according to claim 3, characterized in that: The vacuum induction melting is started by evacuating the vacuum; Preferably, the absolute vacuum degree at the end point of the vacuuming is 0.005-0.1Pa.

5. The preparation method according to claim 3 or 4, characterized in that: The operating temperature of the vacuum induction melting is 1400-1600°C; Preferably, the heating rate of the vacuum induction melting is 20-50°C / s.

6. The preparation method according to any one of claims 3 to 5, characterized in that: The holding time of the vacuum induction melting is 0.5-1h.

7. The preparation method according to any one of claims 3 to 6, characterized in that: The absolute vacuum degree of the centrifugal casting is 0.005-0.1Pa.

8. The preparation method according to any one of claims 3 to 7, characterized in that: The rotation speed of the centrifuge in the centrifugal casting is 400-500r / min.

9. Use of the Ga-Si containing sealing copper alloy as claimed in claim 1 or 2, characterized in that: The application includes preparing metal sealing parts by using the obtained Ga-Si containing sealing copper alloy.

10. The use according to claim 9, characterized in that The sealing temperature of the metal seal is ≥300°C.

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