Soluble magnesium alloy and preparation method thereof

Abstract

The invention belongs to the technical field of alloy preparation, and particularly relates to a soluble magnesium alloy and a preparation method thereof, and the soluble magnesium alloy comprises the following components in percentage by mass: 0.5-1.0% of Ni; 0.5% to 1.5% of Cu; 1.0% to 2.0% of Zn; 3.5% to 10.5% of X; and the balance of Mg and other inevitable elements, wherein X is a rare earth element. The preparation method comprises the steps of smelting, casting, heat treatment and extrusion. The soluble magnesium alloy prepared through mutual matching of all the components has good mechanical performance and dissolution rate.

Description

Technical Field

[0001] The present invention belongs to the technical field of alloy preparation, and particularly relates to a soluble magnesium alloy and a preparation method thereof. Background Art

[0002] China is rich in unconventional oil and gas resources, among which the reserves of shale gas and shale oil rank among the top in the world. In the process of developing unconventional oil and gas resources, the horizontal well staged fracturing technology is mainly adopted. The development of fracturing tools such as bridge plugs has become a key technology for oil and gas resource development. Traditional fracturing tools are mostly made of metal or non-metal materials. After the fracturing operation is completed, they cannot dissolve by themselves and need to be backflowed or milled. This not only increases the complexity and operation time of the fracturing process, but also reduces the production efficiency. Therefore, the research and development of soluble fracturing tools is of great significance for the development of unconventional oil and gas resources. Summary of the Invention

[0003] In order to solve the above problems, the purpose of the present invention is to provide a soluble magnesium alloy and a preparation method thereof. The soluble magnesium alloy prepared by the present invention has good mechanical properties and dissolution properties.

[0004] In order to achieve the above purpose, a soluble magnesium alloy provided by the present invention has the following component ratios by mass percentage: Ni: 0.5%-1.0%; Cu: 0.5%-1.5%; Zn: 1.0%-2.0%; X: 3.5%-10.5%; the balance is Mg and other inevitable elements, where X is a rare earth element.

[0005] Preferably, the rare earth element is one or a combination of more than one of lanthanum, cerium, gadolinium and yttrium.

[0006] Preferably, in the soluble magnesium alloy, the zinc element is introduced by zinc ingots, the magnesium element is introduced by magnesium ingots, magnesium-copper master alloys and magnesium-nickel master alloys, the copper element is introduced by magnesium-copper master alloys, the nickel element is introduced by magnesium-nickel master alloys, and the rare earth element is introduced by rare earth alloys.

[0007] A preparation method of a soluble magnesium alloy includes the following steps:

[0008] S1. Raw material preparation: Prepare magnesium ingots, zinc ingots, magnesium-copper master alloys, magnesium-nickel master alloys and rare earth alloys according to mass percentages;

[0009] S2. Melting and casting: Heat magnesium ingots, zinc ingots and covering agents to 720°C - 730°C for melting, then raise the temperature to 740°C - 770°C, add other master alloys and covering agents, keep warm for 40 min - 60 min after complete melting; after keeping warm, add covering agents for refining for 15 min - 30 min, and cast into ingots at 750°C - 770°C to obtain magnesium alloy ingots.

[0010] S3. Post-treatment: Homogenize the solidified magnesium alloy ingot;

[0011] S4. Extrusion treatment: Keep the post-treated magnesium alloy ingot at 440°C - 460°C for 12 hours and then extrude it to obtain the required soluble magnesium alloy.

[0012] Preferably, in S2, the addition ratio of the covering agent is 3% - 5% of the magnesium content.

[0013] Preferably, the covering agent is Solvent No. 5, and the main components and contents of Solvent No. 5 are: MgCL 2 : 29% ± 2%; KCL: 25% ± 2%; BaCL 2 : 29% ± 2%; CaF 2 : 17% ± 2%; the balance is inevitable impurities.

[0014] Preferably, the voltage during heating is 745V - 755V; the frequency is 610Hz - 625Hz; the power is 35KW - 45KW.

[0015] Preferably, the rare earth alloy is one or a combination of more than one of magnesium-lanthanum master alloy, magnesium-cerium master alloy, magnesium-gadolinium master alloy, and magnesium-yttrium master alloy.

[0016] Preferably, the homogenization treatment in S3 is specifically: Heat the solidified magnesium alloy ingot to 420°C - 440°C and keep it for 12 hours, then air-cool it until the temperature is below 150°C, and then air-cool it to room temperature; among them, the heating rate is 3°C - 5°C / min.

[0017] Preferably, in S4, the extrusion rate of the magnesium alloy ingot is 0.3m / s - 0.5m / s, the extrusion ratio is 9.3 - 14.2; the diameter of the finally obtained soluble magnesium alloy is 85 - 105mm.

[0018] Advantages of the present invention:

[0019] 1. The fracturing tool made of the soluble magnesium alloy prepared by the present invention, compared with the traditional fracturing tool, can dissolve itself in a specific medium in the wellbore after the fracturing operation is completed, eliminating the backflow and drilling and milling processes, reducing the operation risk, saving time, improving the construction efficiency, and at the same time avoiding damage to the reservoir caused by drill cuttings;

[0020] 2. For the soluble magnesium alloy designed by the present invention, the addition of Ni and Cu elements mainly affects the corrosion resistance of the alloy and plays a certain role in promoting the dissolution of the alloy; the addition of Zn element mainly improves the strength of the alloy, and at the same time can cooperate with nickel, etc. to regulate the dissolution of the alloy; the addition of rare earth elements can refine the grains, thereby improving the mechanical properties and casting properties of the magnesium alloy. Description of the Drawings

[0021] Figure 1 This is a schematic flow diagram of the present invention. Detailed Description of the Invention

[0022] The following further elaborates on the present application in conjunction with the drawings and embodiments. The following provides a more detailed description of the specific embodiments of the present invention, but the present invention is not limited to these embodiments. Any improvement or substitution based on the basic spirit of these embodiments still falls within the scope protected by the claims of the present invention.

[0023] The soluble magnesium alloy provided by the present invention, in terms of mass percentage of each component ratio, is as follows: Ni: 0.5% - 1.0%; Cu: 0.5% - 1.5%; Zn: 1.0% - 2.0%; X: 3.5% - 10.5%; the balance is Mg and other inevitable elements, where X is a rare earth element.

[0024] The rare earth element is one or a combination of more of lanthanum, cerium, gadolinium, and yttrium.

[0025] In the raw materials of the soluble magnesium alloy provided by the present invention, zinc element is introduced by zinc ingot, magnesium element is introduced by magnesium ingot, magnesium - copper master alloy, and magnesium - nickel master alloy, copper element is introduced by magnesium - copper master alloy, nickel element is introduced by magnesium - nickel master alloy, and rare earth element is introduced by rare earth alloy.

[0026] The present invention also provides a preparation method for the soluble magnesium alloy, as Figure 1 shown, including the following steps:

[0027] S1. Raw material preparation: Prepare magnesium ingot, zinc ingot, magnesium - copper master alloy, magnesium - nickel master alloy, and rare earth alloy according to the mass percentage; the rare earth alloy is one or a combination of more of magnesium - lanthanum master alloy, magnesium - cerium master alloy, magnesium - gadolinium master alloy, and magnesium - yttrium master alloy.

[0028] S2. Melting and casting: Put magnesium ingot, zinc ingot, and flux into an induction furnace and heat to 720°C - 730°C for melting. Among them, the voltage during heating is 745V - 755V; the frequency is 610Hz - 625Hz; the power is 35KW - 45KW; then raise the temperature to 740°C - 770°C, add other master alloys and flux, keep it melting completely for 40min - 60min; after heat preservation, add flux for refining for 15min - 30min, and cast into ingots at 750°C - 770°C, which is the magnesium alloy ingot; among them, the addition amount of flux is 3% - 5% of the magnesium content; the flux is Solvent No. 5, and the main components and contents of Solvent No. 5 are: MgCL 2 : 29% ± 2%; KCL: 25% ± 2%; BaCL 2 : 29% ± 2%; CaF2 : 17% ± 2%; the balance is inevitable impurities. In the embodiments of the present invention, the main components and contents of Solvent No. 5 are: MgCL 2 : 28%; KCL: 25%; BaCL 2 : 29%; CaF 2 : 17%; the balance is inevitable impurities.

[0029] Add all of Solvent No. 5 during the heat-preserving melting process. If there is exposed molten metal during the melting process, Solvent No. 5 should be replenished in time to prevent the alloy from oxidizing.

[0030] S3. Post-treatment: Homogenize the solidified magnesium alloy ingot; specifically: heat the solidified magnesium alloy ingot to 420°C - 440°C and hold for 12 hours, then air-cool until below 150°C, and then air-cool to room temperature; among them, the heating rate is 3°C - 5°C / min.

[0031] S4. Extrusion treatment: Hold the post-treated magnesium alloy ingot at 440°C - 460°C for 12 hours and then extrude it to obtain the required soluble magnesium alloy; among them, the extrusion rate of the magnesium alloy ingot is 0.3 m / s - 0.5 m / s, and the extrusion ratio is 9.3 - 14.2; the diameter of the finally obtained magnesium alloy is 85 - 105 mm.

[0032] The fracturing tool made of the soluble magnesium alloy prepared by the present invention, compared with the traditional fracturing tool, can dissolve itself in a specific medium in the wellbore after the fracturing operation is completed, eliminating the backflow and drilling and grinding processes, reducing the operation risk, saving time, improving the construction efficiency, and at the same time avoiding damage to the reservoir caused by drill cuttings;

[0033] For the soluble magnesium alloy designed by the present invention, the addition of Ni and Cu elements mainly affects the corrosion resistance of the alloy and plays a certain role in promoting the dissolution of the alloy; the addition of Zn element mainly improves the strength of the alloy, and can also cooperate with nickel, etc. to regulate the dissolution of the alloy; the addition of rare earth elements can refine the grains, thereby improving the mechanical properties and casting properties of the magnesium alloy.

[0034] Example 1

[0035] A soluble magnesium alloy, the component ratios of the soluble magnesium alloy are by mass percentage, Ni: 0.5%; Cu: 1.0%; Zn: 1.5%; Ce: 1.0%; Y: 2.0%; La: 0.5%; the balance is Mg and other inevitable elements.

[0036] The preparation method of the soluble magnesium alloy in this example includes the following steps:

[0037] S1. Raw material preparation: Prepare magnesium ingots, zinc ingots, magnesium-copper master alloy, magnesium-nickel master alloy, magnesium-cerium master alloy, magnesium-yttrium master alloy, and magnesium-lanthanum master alloy according to the above mass percentages of the components;

[0038] S2. Melting and casting: Put the prepared magnesium ingots, zinc ingots, and covering agent into an induction furnace and heat to 730 °C for melting. Among them, the voltage during heating is 750 V; the frequency is 615 Hz; the power is 35 KW; heat up to 750 °C, add magnesium-copper master alloy, magnesium-nickel master alloy, magnesium-cerium master alloy, magnesium-yttrium master alloy, magnesium-lanthanum master alloy, and covering agent. After complete melting, keep warm for 50 min; after keeping warm, add the covering agent for refining for 20 min, and cast into an ingot at 750 °C, which is the magnesium alloy ingot; among them, the addition amount of the covering agent is 3% of the magnesium content;

[0039] S3. Post-treatment: Heat the solidified ingot to 420 °C and keep warm for 12 h, then air-cool until below 150 °C, and then air-cool to room temperature; the heating rate is 3.5 °C / min;

[0040] S4. Extrusion treatment: Keep the post-treated magnesium alloy ingot at 440 °C for 12 h and then extrude it to obtain the required soluble magnesium alloy; among them, the extrusion rate of the magnesium alloy ingot is 0.5 m / s; the extrusion ratio is 14.2; the diameter of the finally obtained soluble magnesium alloy is 85 mm.

[0041] Example 2

[0042] A soluble magnesium alloy, the ratio of each component of the soluble magnesium alloy is calculated by mass percentage, Ni: 1.0%; Cu: 0.5%; Zn: 1.0%; Ce: 1.5%; Y: 1.5%; La: 0.5%; Gd: 3.5%; the balance is Mg and other inevitable elements.

[0043] The preparation method of the soluble magnesium alloy in this example includes the following steps:

[0044] S1. Raw material preparation: Prepare magnesium ingots, zinc ingots, magnesium-copper master alloy, magnesium-nickel master alloy, magnesium-cerium master alloy, magnesium-yttrium master alloy, magnesium-lanthanum master alloy, and magnesium-gadolinium master alloy according to the above mass percentages of the components;

[0045] S2. Melting and casting: Put the prepared magnesium ingots, zinc ingots, and covering agent into an induction furnace and heat to 720 °C for melting. Among them, the voltage during heating is 745 V; the frequency is 620 Hz; the power is 40 KW; heat up to 740 °C, add magnesium-copper master alloy, magnesium-nickel master alloy, magnesium-cerium master alloy, magnesium-yttrium master alloy, magnesium-lanthanum master alloy, magnesium-gadolinium master alloy, and covering agent. After complete melting, keep warm for 40 min; after keeping warm, add the covering agent for refining for 15 min, and cast into an ingot at 760 °C, which is the magnesium alloy ingot; among them, the addition amount of the covering agent is 4% of the magnesium content;

[0046] S3. Post-treatment: Heat the solidified ingot to 430 °C and hold for 12 h, then cool it in air until the temperature is below 150 °C, and then air-cool it to room temperature; the heating rate is 3.0 °C / min;

[0047] S4. Extrusion treatment: Hold the post-treated magnesium alloy ingot at 450 °C for 12 h and then extrude it to obtain the required soluble magnesium alloy; among them, the extrusion rate of the magnesium alloy ingot is 0.3 m / s; the extrusion ratio is 9.3; the diameter of the finally obtained soluble magnesium alloy is 105 mm.

[0048] Example 3

[0049] A soluble magnesium alloy, the component ratio of which is calculated by mass percentage, Ni: 0.5%; Cu: 1.0%; Zn: 2.0%; Y: 3.50%; Gd: 7.0%; the balance is Mg and other inevitable elements.

[0050] The preparation method of the soluble magnesium alloy in this example includes the following steps:

[0051] S1. Raw material preparation: Prepare magnesium ingots, zinc ingots, magnesium-copper master alloy, magnesium-nickel master alloy, magnesium-yttrium master alloy and magnesium-gadolinium master alloy according to the above mass percentage of components;

[0052] S2. Melting and casting: Put the prepared magnesium ingots, zinc ingots and covering agent into an induction furnace and heat to 730 °C for melting. Among them, the voltage during heating is 755 V; the frequency is 610 Hz; the power is 45 KW; heat up to 770 °C, add magnesium-copper master alloy, magnesium-nickel master alloy, magnesium-yttrium master alloy, magnesium-gadolinium master alloy and covering agent, hold for 60 min after complete melting; add the covering agent for refining for 30 min after holding, and cast into an ingot at 750 °C to obtain a magnesium alloy ingot; among them, the addition amount of the covering agent is 5% of the magnesium content;

[0053] S3. Post-treatment: Heat the solidified ingot to 420 °C and hold for 12 h, then cool it in air until the temperature is below 150 °C, and then air-cool it to room temperature; the heating rate is 5 °C / min;

[0054] S4. Extrusion treatment: Hold the post-treated magnesium alloy ingot at 460 °C for 12 h and then extrude it to obtain the required soluble magnesium alloy; among them, the extrusion rate of the magnesium alloy ingot is 0.5 m / s; the extrusion ratio is 12.6; the diameter of the finally obtained soluble magnesium alloy is 90 mm.

[0055] Example 4

[0056] A soluble magnesium alloy, the component ratios of the soluble magnesium alloy are calculated by mass percentage, Ni: 0.75%; Cu: 1.5%; Zn: 2.0%; Ce: 2.0%; Y: 3.5%; Gd: 2.5%; the balance is Mg and other inevitable elements.

[0057] The preparation method of the soluble magnesium alloy in this embodiment includes the following steps:

[0058] S1. Raw material preparation: Prepare magnesium ingots, zinc ingots, magnesium-copper master alloy, magnesium-nickel master alloy, magnesium-cerium master alloy, magnesium-yttrium master alloy and magnesium-gadolinium master alloy according to the above component mass percentages;

[0059] S2. Melting and casting: Put the prepared magnesium ingots, zinc ingots and covering agent into an induction furnace and heat to 725 °C for melting. Among them, the voltage during heating is 750 V; the frequency is 625 Hz; the power is 45 KW; heat up to 760 °C, add magnesium-copper master alloy, magnesium-nickel master alloy, magnesium-cerium master alloy, magnesium-yttrium master alloy, magnesium-gadolinium master alloy and covering agent, keep warm for 60 min after complete melting; add covering agent for refining for 30 min after keeping warm, and cast into ingots at 770 °C, which is the magnesium alloy ingot; among them, the addition amount of the covering agent is 4% of the magnesium content;

[0060] S3. Post-treatment: Heat the solidified ingot to 440 °C and keep warm for 12 h, then air-cool until below 150 °C, and then air-cool to room temperature; the heating rate is 4 °C / min;

[0061] S4. Extrusion treatment: Keep the magnesium alloy ingot after post-treatment at 450 °C for 12 h and then extrude to obtain the required soluble magnesium alloy; among them, the extrusion rate of the magnesium alloy ingot is 0.4 m / s; the extrusion ratio is 10.3; the diameter of the finally obtained soluble magnesium alloy is 100 mm.

[0062] Table 1 Test data of mechanical properties and dissolution rate of Examples 1-4 at 90 °C

[0063]

[0064]

[0065] According to Table 1, for the soluble magnesium alloy materials prepared in Examples 1-4 of the present invention, their dissolution rate is above 55 mg / cm 2 / h, and the mechanical properties are good. The fracturing tool made of the soluble magnesium alloy of the present invention, compared with the traditional fracturing tool, can dissolve itself in the specific medium in the wellbore after the fracturing operation is completed, eliminating the backflow and drilling and milling processes, reducing the operation risk, saving time, improving the construction efficiency, and at the same time avoiding damage to the reservoir caused by drill cuttings.

Claims

1. A soluble magnesium alloy, characterized in that: The distribution ratio of each component of the soluble magnesium alloy is calculated by mass percentage, Ni: 0.5%-1.0%; Cu: 0.5%-1.5%; Zn: 1.0%-2.0%; X: 3.5%-10.5%; the remainder is Mg and other inevitable elements, wherein X is a rare earth element.

2. The soluble magnesium alloy according to claim 1, characterized in that The rare earth element is a combination of one or more of lanthanum, cerium, gadolinium and yttrium.

3. The soluble magnesium alloy according to claim 1, characterized in that In the soluble magnesium alloy, zinc is introduced from zinc ingots, magnesium is introduced from magnesium ingots and magnesium-copper master alloys and magnesium-nickel master alloys, copper is introduced from magnesium-copper master alloys, nickel is introduced from magnesium-nickel master alloys, and rare earth elements are introduced from rare earth alloys.

4. The method for preparing a soluble magnesium alloy according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1. Raw material preparation: magnesium ingots, zinc ingots, magnesium-copper master alloys, magnesium-nickel master alloys and rare earth alloys are prepared according to mass percentage; S2. Melting and casting: heat the magnesium ingot, zinc ingot and covering agent to 720℃-730℃ to melt, then heat to 740℃-770℃, add other master alloys and covering agent, keep warm for 40min-60min after complete melting; add covering agent and refine for 15min-30min after keeping warm, and cast into ingot at 750℃-770℃, which is magnesium alloy ingot; S3. Post-processing: homogenizing the solidified magnesium alloy ingot; S4. Extrusion treatment: The post-treated magnesium alloy ingot is kept at 440°C-460°C for 12 hours and then extruded to obtain the desired soluble magnesium alloy.

5. The method for preparing a soluble magnesium alloy according to claim 4, characterized in that: In the S2, the covering agent is added in a proportion of 3%-5% of the magnesium content.

6. The method for preparing a soluble magnesium alloy according to claim 5, characterized in that: The covering agent is solvent No. 5, and the main components and contents of solvent No. 5 are: MgCL2: 29%±2%; KCL: 25%±2%; BaCL2: 29%±2%; CaF2: 17%±2%; the remainder is inevitable impurities.

7. The method for preparing a soluble magnesium alloy according to claim 4, characterized in that: In S2, the voltage during heating is 745V-755V; the frequency is 610Hz-625Hz; and the power is 35KW-45KW.

8. The method for preparing a soluble magnesium alloy according to claim 4, characterized in that: The rare earth alloy is a combination of one or more of a magnesium-lanthanum master alloy, a magnesium-cerium master alloy, a magnesium-gadolinium master alloy and a magnesium-yttrium master alloy.

9. The method for preparing a soluble magnesium alloy according to claim 4, characterized in that: The homogenization treatment in S3 is specifically as follows: placing the solidified magnesium alloy ingot in a heat treatment furnace, heating it to 420°C-440°C and keeping it at that temperature for 12 hours, then air cooling it to below 150°C, and air cooling it to room temperature; wherein the heating rate is 3°C-5°C / min.

10. The method for preparing a soluble magnesium alloy according to claim 4, characterized in that: In the S4, the extrusion rate of the magnesium alloy ingot is 0.3m / s-0.5m / s, and the extrusion ratio is 9.3-14.2; the diameter of the soluble magnesium alloy finally obtained is 85-105mm.

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