Rhodium-containing copper alloy and preparation method and application thereof

Abstract

The invention provides a rhodium-containing copper alloy and a preparation method and application thereof. The element composition of the rhodium-containing copper alloy comprises 0.5-5.0 wt% of rhodium and the balance of copper. The preparation method of the rhodium-containing copper alloy comprises the steps that a proper amount of copper powder and a proper amount of rhodium powder are ground and evenly mixed, and then the mixed powder is pressed into a cylinder in a cold pressing mode; cutting, cleaning and blow-drying the pure copper block; the cylinder and the dried pure copper block are subjected to electric arc melting, and a copper-rhodium intermediate alloy is obtained; and the copper-rhodium intermediate alloy and a proper amount of pure copper blocks are subjected to vacuum induction heating and centrifugal casting, and the rhodium-containing copper alloy is obtained. The sealing temperature of the rhodium-containing copper alloy is higher than 300 DEG C, the sealing performance of the rhodium-containing copper alloy is better than that of an existing copper gasket material, and the requirements of underground sealing pieces can be met.

Description

Technical Field

[0001] The invention relates to a rhodium-containing copper alloy and a preparation method and application thereof, belonging to the technical field of alloy materials. Background Art

[0002] In the oil drilling industry, rubber seals are used to seal between expansion pipes and original pipes according to the different needs of downhole operations. Rubber seals have the advantages of good sealing performance, low expansion pressure, easy operation, high reliability, etc., and are widely used in the drilling industry with relatively mature technology. Rubber is widely used as a sealing element in downhole operations due to its high elasticity, high wear resistance and suitable mechanical strength.

[0003] As oil and gas development moves toward deep and ultra-deep wells, the temperature of the operating formation increases and the corrosive medium increases, making it difficult for rubber seals to continue to maintain good sealing performance. At the same time, long-term high-temperature environments underground will also cause rubber aging and failure, bringing huge risks to underground operation safety. Therefore, developing a high-temperature resistant soft metal material for underground high-temperature environments to replace existing rubber materials to achieve sealing functions is of great significance for deep and ultra-deep well oil and gas resource exploitation.

[0004] At present, the available metal sealing materials include Cu, Ag, In, stainless steel and high temperature alloys. Among them, Ag and In alloys are softer in texture and have good sealing performance, but they are not strong enough, the operating temperature is low, and the cost is high; stainless steel and high temperature alloys have higher operating temperatures and can meet high temperature sealing requirements, but because of their hard material, high expansion pressure, small sealing interference, their sealing performance is poor. Copper alloys have certain strength and good plasticity and toughness, and are often used as sealing gaskets. However, the current copper alloy gaskets also have the following disadvantages: first, their plasticity and viscosity are insufficient, and their sealing performance is not as good as Ag and In alloys; second, the current sealing temperature of copper alloys is low, below 300°C.

[0005] Therefore, there is an urgent need in the art to develop a copper alloy with a sealing temperature greater than 300° C. and a sealing performance better than that of existing copper gasket materials, which can meet the needs of downhole seals. Summary of the invention

[0006] In order to solve the above technical problems, the purpose of the present invention is to provide a new type of copper alloy, the sealing temperature of which is greater than 300°C, and the sealing performance of which is better than that of existing copper gasket materials, and can meet the needs of downhole seals.

[0007] The present invention also aims to provide a method for preparing the copper alloy.

[0008] The present invention also aims to provide the application of the copper alloy as a downhole sealing material.

[0009] To achieve the above object, the present invention first provides a rhodium-containing copper alloy, wherein the element composition of the rhodium-containing copper alloy includes 0.5-5.0wt% of rhodium and the balance is copper.

[0010] According to a specific embodiment of the present invention, preferably, the rhodium content in the elemental composition of the rhodium-containing copper alloy can be 0.5wt%, 1.0wt%, 1.5wt%, 2.0wt%, 2.5wt%, 3.0wt%, 3.5wt%, 4.0wt%, 4.5wt%, 5.0wt% or the like, or a content range composed of any two of the above specific contents.

[0011] According to a specific embodiment of the present invention, preferably, the element composition of the rhodium-containing copper alloy comprises 0.5-2.5 wt % of rhodium, with the remainder being copper.

[0012] According to a specific embodiment of the present invention, preferably, the element composition of the rhodium-containing copper alloy comprises 1.5-5.0 wt% of rhodium, with the remainder being copper.

[0013] According to a specific embodiment of the present invention, preferably, the element composition of the rhodium-containing copper alloy comprises 1.5-2.5 wt % of rhodium, with the remainder being copper.

[0014] According to a specific embodiment of the present invention, preferably, the rhodium-containing copper alloy further contains unavoidable impurities.

[0015] According to a specific embodiment of the present invention, preferably, the tensile strength of the rhodium-containing copper alloy at 300° C. is 180 MPa-220 MPa.

[0016] According to a specific embodiment of the present invention, preferably, the leakage rate of the rhodium-containing copper alloy in a helium environment is ≤10 -3 Pa·m 3 / s.

[0017] According to a specific embodiment of the present invention, preferably, the metallographic structure of the rhodium-containing copper alloy is an equiaxed crystal structure.

[0018] The present invention also provides a method for preparing the above-mentioned rhodium-containing copper alloy, which comprises the following steps:

[0019] (1) grinding and uniformly mixing an appropriate amount of copper powder and an appropriate amount of rhodium powder, and then pressing the mixed powder into a cylinder by cold pressing;

[0020] (2) Splitting, cleaning and drying the pure copper block;

[0021] (3) arc melting the cylinder and the pure copper block dried in step (2) to obtain a copper-rhodium intermediate alloy;

[0022] (4) vacuum induction heating and centrifugal casting are performed on the copper-rhodium intermediate alloy and an appropriate amount of pure copper block to obtain the rhodium-containing copper alloy.

[0023] According to a specific embodiment of the present invention, preferably, in the above preparation method, the purity of the copper powder and the pure copper block is: copper content ≥ 99.95wt%; the purity of the rhodium powder is: rhodium content ≥ 99.95wt%.

[0024] According to a specific embodiment of the present invention, preferably, in the above preparation method, in step (1), the diameter of the cylinder is 1-2 cm, more preferably 15 mm.

[0025] According to a specific embodiment of the present invention, preferably, in the above-mentioned preparation method, the step (2) comprises: cutting the pure copper block into a size of 2-3 cm, and then placing it in a 5% dilute sulfuric acid solution for pickling, and then ultrasonically cleaning the pickled pure copper block with alcohol for 3-4 times, and then drying and sealing it for storage.

[0026] According to a specific embodiment of the present invention, preferably, in the above preparation method, in step (3), the arc melting is carried out using a vacuum arc melting furnace.

[0027] According to a specific embodiment of the present invention, preferably, in the above preparation method, in step (3), when arc melting is performed, the cylinder is placed under the pure copper block.

[0028] According to a specific embodiment of the present invention, preferably, in the above preparation method, in step (3), the mass fraction of rhodium in the copper-rhodium master alloy is 3%-30%.

[0029] According to a specific embodiment of the present invention, preferably, in the above preparation method, in step (4), during the vacuum induction heating process, the copper-rhodium intermediate alloy and an appropriate amount of pure copper block are subjected to vacuum induction heating in a graphite crucible, wherein the copper-rhodium intermediate alloy is placed on the top.

[0030] According to a specific embodiment of the present invention, preferably, in the above-mentioned preparation method, in step (4), the vacuum induction heating process comprises: firstly evacuating the vacuum, and when the vacuum degree reaches the requirement, heating is started at a heating rate of 20°C / s to 50°C / s, heated to a temperature range of 1300°C to 1500°C, kept warm for 0.5 to 1 hour, and then centrifugal casting is performed.

[0031] According to a specific embodiment of the present invention, preferably, the temperature of vacuum induction heating can be specific temperature values ​​such as 1300°C, 1350°C, 1400°C, 1450°C, 1500°C, or a temperature range composed of two of the above specific temperature values, such as 1350°C-1500°C, 1400°C-1500°C, 1450°C-1500°C, 1350°C-1450°C, 1350°C-1400°C, 1400°C-1450°C, etc.

[0032] According to a specific embodiment of the present invention, preferably, in the above-mentioned preparation method, the rotation speed of the centrifuge used in the centrifugal casting is 400-500r / min, for example, 400r / min, 420r / min, 440r / min, 460r / min, 480r / min, 500r / min, or a range consisting of any two of the above-mentioned rotation speeds as endpoints, for example, 420-480r / min, 440-460r / min.

[0033] According to a specific embodiment of the present invention, preferably, the above preparation method may include the following specific steps:

[0034] (1) Raw materials: The purity of the raw materials used is: ≥99.95wt% copper powder and pure copper block, ≥99.95wt% rhodium powder.

[0035] (2) Raw material weighing, batching, and cold pressing: Weigh a certain mass of copper powder and a certain mass of rhodium powder, grind and mix them evenly, and then use cold pressing to press the mixed powder into a cylinder with a diameter of 15 mm.

[0036] (3) Splitting, cleaning and drying of the pure copper block: Cut the copper block into pieces of 2-3 cm in size, weigh it, and then put it into a 5% dilute sulfuric acid solution for pickling. Then, ultrasonically clean the pickled copper block with alcohol for 3-4 times, then blow dry and seal it for storage.

[0037] (4) Vacuum arc melting of Rh-Cu master alloy: The mixed powder pressed cylinder and the pure copper block are placed in a vacuum arc melting furnace for arc melting to obtain a copper-rhodium master alloy, wherein the mixed powder pressed cylinder is placed at the bottom of the metal Cu block, and finally a Rh-Cu master alloy with a Rh mass fraction of 3%-30% is obtained.

[0038] (5) Copper-rhodium alloy casting: vacuum induction heating and centrifugal casting furnace are used for casting. Rh-Cu master alloy with a certain rhodium content and pure copper block are placed in a graphite crucible for vacuum induction heating, wherein the Rh-Cu master alloy is placed on the top. The specific steps are: first, vacuum is evacuated. When the vacuum degree reaches the requirement, heating is started at a heating rate of 20℃ / s to 50℃ / s, and the temperature range is 1300℃ to 1500℃. After keeping warm for 0.5 to 1 hour, centrifugal casting is then used for casting. The centrifuge rotation speed is 400-500r / min. The ingot furnace is then cooled to room temperature to obtain a copper alloy ingot containing rhodium.

[0039] The present invention also provides application of the above-mentioned copper alloy containing rhodium as a downhole sealing material.

[0040] According to a specific embodiment of the present invention, preferably, the use temperature of the downhole sealing material is 300°C, that is, the above-mentioned rhodium-containing copper alloy is a sealing material used in a 300°C environment.

[0041] According to a specific embodiment of the present invention, preferably, the downhole seal is a gasket, that is, the above-mentioned rhodium-containing copper alloy is made into a gasket for use.

[0042] The tensile strength of existing copper alloys at 300°C is less than 150 MPa, and the leakage rate in a helium environment is about 5×10 -2 Pa·m 3 / s. The sealing temperature of the rhodium-containing copper alloy provided by the present invention is greater than 300° C., and the sealing performance is better than that of the existing copper gasket material, and can meet the needs of underground sealing parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is the metallographic structure diagram of the copper alloy obtained in Example 1. DETAILED DESCRIPTION

[0044] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0045] Test method:

[0046] 1. The tensile strength test is carried out in the following manner:

[0047] Metal material tensile test (room temperature) GB / T 228.1-2021;

[0048] Metal material tensile test (high temperature) GB / T 228.2-2015.

[0049] 2. The leak rate test in helium environment is carried out in the following manner:

[0050] Non-destructive testing Helium leak detection method GB / T 15823-2009.

[0051] Example 1

[0052] This embodiment provides a copper alloy containing Rh, the total weight of the ingot of which is 108 g, and the mass percentage of each alloy component is: 0.5 wt.% Rh, and the rest is Cu.

[0053] The Rh-containing copper alloy is prepared according to the following method:

[0054] First, weigh 5g copper powder and 0.54g rhodium powder for grinding to make them evenly mixed, and use cold pressing to press the mixed powder into a cylinder with a diameter of 15mm; secondly, cut the Cu block into a size of 2-3cm, weigh 102.46g, and then put it into a 5% dilute sulfuric acid solution for pickling, and then ultrasonically clean the pickled Cu block with alcohol for 3-4 times and seal it for storage; then put the mixed powder pressed cylinder and 10g Cu block into a vacuum arc melting furnace for arc melting to obtain Rh-Cu master alloy, wherein the mixed powder pressed cylinder is placed at the bottom of the metal Cu block; finally, put the Rh-Cu master alloy and the remaining pure Cu block into a graphite crucible for induction melting, wherein the Rh-Cu master alloy is placed on the top. The induction heating rate is 20℃ / s, heated to 1300℃ and kept warm for 0.5 hours, then centrifugally cast, wherein the centrifuge rotation speed is 400r / min, and finally the furnace is cooled to room temperature to obtain a copper alloy ingot containing Rh.

[0055] After testing, the tensile strength of the Rh-containing sealing copper alloy at 300°C was 183MPa, and the leakage rate in a helium environment was ≤10 -3 Pa·m 3 / s.

[0056] The metallographic structure of the Rh-containing copper alloy prepared in this embodiment is as follows: Figure 1 As shown, it is specifically an equiaxed crystal structure.

[0057] Example 2

[0058] This embodiment provides a copper alloy containing Rh, the total weight of the ingot of which is 108 g, and the mass percentage of the alloy components is: 1.5 wt.% Rh and the rest is Cu.

[0059] The Rh-containing copper alloy is prepared according to the following method:

[0060] First, weigh 5g copper powder and 1.62g rhodium powder and grind them to make them evenly mixed, and use cold pressing to press the mixed powder into a cylinder with a diameter of 15mm; secondly, cut the Cu block into a size of 2-3cm, weigh 101.38g, and then put it into a 5% dilute sulfuric acid solution for pickling, and then ultrasonically clean the pickled Cu block with alcohol for 3-4 times and seal it for storage; then put the mixed powder pressed cylinder and 10g Cu block into a vacuum arc melting furnace for arc melting to obtain Rh-Cu master alloy, wherein the mixed powder pressed cylinder is placed at the bottom of the metal Cu block; finally, put the Rh-Cu master alloy and the remaining pure Cu block into a graphite crucible for induction melting, wherein the Rh-Cu master alloy is placed on the top. The induction heating rate is heated to 1400℃ at a heating rate of 20℃ / s, and then kept warm for 0.5 hours, and then centrifugally cast, wherein the centrifuge rotation speed is 500r / min, and the furnace is cooled to room temperature to obtain a copper alloy ingot containing Rh.

[0061] After testing, the tensile strength of the Rh-containing sealing copper alloy at 300°C was 186MPa, and the leakage rate in a helium environment was ≤10 -3 Pa·m 3 / s.

[0062] Example 3

[0063] This embodiment provides a sealing copper alloy containing Rh, the total weight of the ingot of which is 108 g, and the mass percentage of the alloy components is: 2.5 wt.% Rh and the rest is Cu.

[0064] The Rh-containing copper alloy is prepared according to the following method:

[0065] First, weigh 5g copper powder and 2.7g rhodium powder and grind them to make them evenly mixed, and use cold pressing to press the mixed powder into a cylinder with a diameter of 15mm; secondly, cut the Cu block into a size of 2-3cm, weigh 100.3g, and then put it into a 5% dilute sulfuric acid solution for pickling, and then ultrasonically clean the pickled Cu block with alcohol for 3-4 times and seal it for storage; then put the mixed powder pressed cylinder and 10g Cu block into a vacuum arc melting furnace for arc melting to obtain Rh-Cu master alloy; wherein the mixed powder pressed cylinder is placed at the bottom of the metal Cu block; finally, put the Rh-Cu master alloy and the remaining pure Cu block into a graphite crucible for induction melting, wherein the Rh-Cu master alloy is placed on the top. The induction heating rate is heated to 1400℃ at a heating rate of 20℃ / s, and then kept warm for 0.5 hours, and then centrifugally cast, wherein the centrifuge rotation speed is 450r / min, and the furnace is cooled to room temperature to obtain a copper alloy ingot containing Rh.

[0066] After testing, the tensile strength of the Rh-containing sealing copper alloy at 300°C was 190MPa, and the leakage rate in a helium environment was ≤10 -3 Pa·m 3 / s.

[0067] Example 4

[0068] This embodiment provides a sealing copper alloy containing Rh, the total weight of the ingot of which is 108 g, and the mass percentage of the alloy components is: 5.0 wt.% Rh and the rest is Cu.

[0069] The Rh-containing copper alloy is prepared according to the following method:

[0070] First, weigh 5g copper powder and 5.4g rhodium powder and grind them to make them evenly mixed, and use cold pressing to press the mixed powder into a cylinder with a diameter of 15mm; secondly, cut the Cu block into a size of 2-3cm, weigh 97.6g, and then put it into a 5% dilute sulfuric acid solution for pickling, and then ultrasonically clean the pickled Cu block with alcohol for 3-4 times and seal it for storage; then put the mixed powder pressed cylinder and 10g Cu block into a vacuum arc melting furnace for arc melting to obtain Rh-Cu master alloy; finally, put the Rh-Cu master alloy and the remaining pure Cu block into a graphite crucible for induction melting, wherein the Rh-Cu master alloy is placed on the top. The induction heating rate is heated to 1500℃ at a heating rate of 20℃ / s, and then kept warm for 1 hour, and then centrifugally cast, wherein the centrifuge rotation speed is 500r / min, and the furnace is cooled to room temperature to obtain a copper alloy ingot containing Rh.

[0071] After testing, the tensile strength of the Rh-containing sealing copper alloy at 300°C was 213MPa, and the leakage rate in a helium environment was ≤10 -3 Pa·m 3 / s.

[0072] It can be seen from the above embodiments that the Rh-containing copper alloy provided by the present invention has a sealing temperature greater than 300° C., has better sealing performance than existing copper gasket materials, and can meet the needs of downhole seals.

Claims

1. A copper alloy containing rhodium, in, The element composition of the rhodium-containing copper alloy includes 0.5-5.0 wt % of rhodium and the balance is copper.

2. The rhodium-containing copper alloy according to claim 1, in, The element composition of the rhodium-containing copper alloy includes 0.5-2.5 wt % of rhodium and the balance is copper.

3. The rhodium-containing copper alloy according to claim 1, in, The element composition of the rhodium-containing copper alloy includes 1.5-5.0 wt % of rhodium and the balance is copper.

4. The rhodium-containing copper alloy according to claim 1, in, The element composition of the rhodium-containing copper alloy includes 1.5-2.5 wt % of rhodium and the balance is copper.

5. The rhodium-containing copper alloy according to any one of claims 1 to 4, in, The rhodium-containing copper alloy also contains inevitable impurities.

6. The rhodium-containing copper alloy according to claim 1, in, The tensile strength of the rhodium-containing copper alloy at 300° C. is 180 MPa-220 MPa.

7. The rhodium-containing copper alloy according to claim 1, in, The leakage rate of the rhodium-containing copper alloy in a helium environment is ≤10 -3 Pa·m 3 / s.

8. The rhodium-containing copper alloy according to any one of claims 1 to 4, in, The metallographic structure of the rhodium-containing copper alloy is an equiaxed crystal structure.

9. The method for preparing a rhodium-containing copper alloy according to any one of claims 1 to 8, wherein The following steps are involved: (1) grinding and uniformly mixing an appropriate amount of copper powder and an appropriate amount of rhodium powder, and then pressing the mixed powder into a cylinder by cold pressing; (2) Splitting, cleaning and drying the pure copper block; (3) arc melting the cylinder and the pure copper block dried in step (2) to obtain a copper-rhodium intermediate alloy; (4) vacuum induction heating and centrifugal casting are performed on the copper-rhodium intermediate alloy and an appropriate amount of pure copper block to obtain the rhodium-containing copper alloy.

10. The preparation method according to claim 9, in, The purity of the copper powder and the pure copper block is: copper content ≥ 99.95wt%; The purity of the rhodium powder is: rhodium content ≥ 99.95wt%.

11. The preparation method according to claim 9, in, In step (1), the diameter of the cylinder is 1-2 cm, preferably 15 mm.

12. The preparation method according to claim 9, in, The step (2) comprises: cutting the pure copper block into pieces of 2-3 cm in size, and then placing it in a 5% dilute sulfuric acid solution for pickling, and then ultrasonically cleaning the pickled pure copper block with alcohol for 3-4 times, and then drying and sealing it for storage.

13. The preparation method according to claim 9, in, In step (3), during arc melting, the cylinder is placed below the pure copper block.

14. The preparation method according to claim 9, in, In step (3), the mass fraction of rhodium in the copper-rhodium master alloy is 3%-30%.

15. The preparation method according to claim 9, in, In step (4), during the vacuum induction heating process, the copper-rhodium master alloy and an appropriate amount of pure copper block are subjected to vacuum induction heating in a graphite crucible, wherein the copper-rhodium master alloy is placed on the top.

16. The preparation method according to claim 9 or 15, in, In step (4), the vacuum induction heating process includes: first, evacuating the vacuum, and when the vacuum degree reaches the required level, heating is started at a heating rate of 20°C / s to 50°C / s, heating to a temperature range of 1300°C to 1500°C, keeping the temperature for 0.5 to 1 hour, and then centrifugal casting is performed.

17. The preparation method according to claim 9, in, The rotation speed of the centrifuge used in the centrifugal casting is 400-500r / min.

18. Use of the rhodium-containing copper alloy according to any one of claims 1 to 8 as a downhole sealing material.

19. The use according to claim 18, in, The use temperature of the downhole sealing material is 300°C.

20. The use according to claim 18, in, The downhole sealing element is a gasket.

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