Soluble magnesium alloy extrusion method

Abstract

The invention belongs to the technical field of oil and gas development, and discloses a soluble magnesium alloy extrusion method, soluble magnesium alloy comprises, by mass, 85-95 wt% of Mg, 3-8 wt% of Al, 1-3 wt% of Zn, 0.5-2 wt% of Cu and 0.5-2 wt% of Ni, the purity of all the components is larger than or equal to 99.9%, and the soluble magnesium alloy extrusion method comprises the steps that raw materials are prepared; smelting and casting; pretreating the blank; according to the invention, the mechanical property of the soluble magnesium alloy is improved, the grain boundary defect is reduced, and the resistance of dislocation motion is improved by increasing the grain boundary area, so that the strength and plasticity of the alloy are greatly improved, and the soluble magnesium alloy can bear higher underground pressure; and the structural strength requirement of a high-pressure fracturing tool in shale gas development is completely met.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas development technology, specifically a method for extruding soluble magnesium alloys. Background Technology

[0002] In the oil and gas field development sector, with the large-scale exploitation of unconventional resources such as shale gas and tight oil and gas, fracturing technology has been widely applied as a key technology for enhancing production. Downhole tools used in the fracturing process, such as bridge plugs and fracturing balls, require flowback or milling after operation. This not only increases operation time and costs but may also damage the wellbore and even cause wellbore blockage. Therefore, developing tools made of soluble materials that can automatically dissolve downhole has become an important direction for industry development.

[0003] Soluble magnesium alloys, with their advantages of low density, moderate strength, and controllable solubility, have become ideal materials for manufacturing soluble downhole tools. They can gradually dissolve in drilling fluids or formation water containing electrolytes such as potassium and sodium, requiring no further treatment, which can significantly improve operational efficiency and reduce costs. However, existing soluble magnesium alloys still have several shortcomings: on the one hand, as-cast soluble magnesium alloys suffer from coarse grains and uneven microstructure, resulting in low mechanical properties (tensile strength typically below 200 MPa, elongation at break less than 5%), making it difficult to meet the structural strength requirements of tools in high-pressure deep wells; on the other hand, the dissolution rate of some soluble magnesium alloys is either too fast (exceeding 30 mg / cm³ in ambient temperature well fluids) or... 2 The tool fails prematurely due to speed ( / h), or it is too slow (below 10 mg / cm). 2 / h) cannot remove the plug in time and is difficult to adapt to the dissolution requirements of different well conditions.

[0004] To improve the performance of soluble magnesium alloys, the industry often uses hot extrusion. Hot extrusion refines grains and eliminates casting defects through plastic deformation, thereby improving the mechanical properties of the alloy. However, existing hot extrusion technology has the following problems in the application of soluble magnesium alloys: First, the matching between extrusion process parameters (such as temperature, extrusion ratio, speed, etc.) and alloy composition is insufficient, resulting in some alloys showing increased strength after extrusion but significantly decreased plasticity or excessive fluctuations in the dissolution rate; Second, the process flow is not standardized enough. For example, incomplete pretreatment of raw materials leads to excessive impurity content, improper control of the protective atmosphere during melting causes alloy oxidation, and uneven preheating of the die causes deviations in the dimensional accuracy of the extruded parts. These problems all affect the consistency and stability of soluble magnesium alloy products. Summary of the Invention

[0005] The purpose of this invention is to provide a soluble magnesium alloy extrusion method to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a soluble magnesium alloy, wherein the soluble magnesium alloy comprises the following components by mass percentage: Mg 85-95wt%, Al 3-8wt%, Zn 1-3wt%, Cu 0.5-2wt%, Ni 0.5-2wt%, and the purity of each component is ≥99.9%.

[0007] A method for extruding a soluble magnesium alloy, the method comprising the following steps: S1. Raw material preparation: accurately weighing the pure metal of the soluble magnesium alloy using an electronic balance with an accuracy of 0.001g to ensure an error ≤ ±0.05wt%; cleaning the surface oxide layer of the metal raw material by removing obvious oxide scale with a wire brush and wiping the surface with a 95% ethanol solution until no stains remain, to ensure elemental purity during smelting; S2. Melting and Casting: Melting is carried out in a protective atmosphere of 0.5% SF6 + 99.5% CO2. First, the crucible is preheated to 300-400℃ to remove moisture, then magnesium ingots are added, and the temperature is raised to 720-750℃ to completely melt them. Then, other metals are added in the order of Al, Zn, Cu, Ni. After all the metals have melted, the temperature is raised to 750-780℃ and stirred for 30-50 minutes to make the alloy composition uniform. After melting, the alloy liquid is allowed to stand for 10-15 minutes to remove air bubbles, and then poured into a low-carbon steel mold preheated to 150-200℃ at 680-720℃. The inner surface of the mold is pre-coated with a release agent. After casting, the alloy is allowed to cool naturally to room temperature in the air to form a cast alloy. S3. Billet Pretreatment: The as-cast alloy is machined into cylindrical billets with a diameter of 50-100mm and a length of 100-200mm using a lathe. After machining, the dimensions are measured with a micrometer to ensure that the dimensional accuracy is within ±0.1mm. The billets are placed in a box-type heat treatment furnace and heated to 380-420℃ at a rate of 5-10℃ / min. The temperature is held for 4-8 hours to achieve microstructure homogenization. During the holding process, the temperature fluctuation inside the furnace is controlled within ±5℃. After the holding is completed, the temperature is first reduced to 300℃ at a rate of 5℃ / min, and then cooled to 200℃ with the furnace to avoid internal stress caused by rapid cooling. S4. Hot Extrusion Molding: The billet is hot-extruded at a temperature of 380-420℃, with an extrusion ratio of 5-20 and an extrusion speed of 5-20 mm / min. Before extrusion, graphite lubricant is uniformly coated on the surface of the billet. This step includes several sub-steps. Among them, equipment and mold inspection must ensure that the performance parameters of the extruder are normal, mold preheating must ensure uniform temperature, billet transfer must be fast and temperature loss must be reduced, segmented extrusion must control the pressure and speed of different stages, cooling and straightening must ensure the dimensional accuracy of the profile, and mold maintenance can extend the mold service life. Through the coordinated operation of these sub-steps, high-performance soluble magnesium alloy extrusions are finally obtained.

[0008] Preferably, in the raw material preparation step, the metal purity is 99.95%-99.98%, and vacuum packaging or inert gas protection is used during storage to prevent surface oxidation; for low-melting-point metals such as zinc and copper, they need to be pre-cut into small pieces ≤50mm to shorten the melting time.

[0009] Preferably, in the melting and casting step, a silicon nitride stirring paddle is used, and the stirring is alternately at a speed of 30-50 r / min to ensure that the alloy element distribution deviation is ≤0.1wt%; during casting, an inclined pouring method is used, and the liquid flow velocity is controlled at 0.5-1 m / s to avoid slag entrapment.

[0010] Preferably, the equipment and mold inspection sub-steps for hot extrusion molding include: hydraulic system level ≥ 2 / 3 of the scale, oil temperature 30-50℃; mold core and mold sleeve clearance ≤ 0.05mm; extrusion rod reciprocating 3 times under no load without jamming; stroke error ≤ ±0.5mm.

[0011] Preferably, in the preheating sub-step of the hot extrusion molding die, the die needs to be heated once every hour for 4 hours in advance according to the step temperature change of 100℃→200℃→300℃→extrusion temperature, with the working temperature difference ≤5℃, and the temperature data is recorded once every 10 minutes by thermocouple.

[0012] Preferably, in the surface treatment sub-step of the hot extrusion forming blank, graphite lubricant is mixed with anhydrous ethanol at a ratio of 1:3, and sprayed at a distance of 20-30cm using a 0.5mm nozzle at a viscosity of 50-80mPa・s, with a coating thickness of 0.1-0.2mm, and then allowed to air dry for 10 minutes before use.

[0013] Preferably, the segmented extrusion sub-steps of the hot extrusion molding include: a start-up stage where 50 mm is advanced at 30% of the rated pressure; a stabilization stage where the extrusion temperature deviation is maintained at 60%-80% of the rated pressure to ≤±5℃; and a finish-up stage where the final 10 mm stroke is completed at 40% of the rated pressure, with the entire process monitored in real time by an infrared thermometer.

[0014] Preferably, in the hot extrusion forming billet transfer and loading step, the time from billet exiting the furnace to loading into the cylinder is ≤30s, and the temperature drop is ≤20℃; the deviation between the billet axis and the extrusion cylinder axis is ≤1mm during loading, and the end cap is closed after positioning and fixing to prevent eccentric deformation during extrusion.

[0015] Preferably, the cooling, straightening, and die maintenance sub-steps of the hot extrusion molding include: the extruded profile is air-cooled to below 150°C at a wind speed of 10-15 m / s, and the multi-roll straightener is used to gradually halve the initial reduction of 0.5 mm until the straightness is ≤1 mm / m; after extruding every 5 blanks, the die working zone is cleaned and polished until Ra≤0.8 μm, and the die is replaced when the wear exceeds 0.1 mm.

[0016] The beneficial effects of this invention are as follows: 1. In this invention, a precisely designed hot extrusion process enhances the mechanical properties of soluble magnesium alloys. During extrusion, the temperature range of 380-420℃ and the extrusion ratio of 5-20 work synergistically to induce severe plastic deformation and breakage of the originally coarse dendrites in the as-cast alloy, ultimately forming a uniform and fine equiaxed grain structure. The grain size can be refined from 50-100μm in the as-cast state to 8-15μm. This refinement effect not only reduces grain boundary defects but also increases the resistance to dislocation movement by increasing the grain boundary area, thereby significantly improving the strength and plasticity of the alloy. This allows the soluble magnesium alloy to withstand higher downhole pressures, fully meeting the structural strength requirements of high-pressure fracturing tools (such as bridge plugs and sliding sleeves) in shale gas development. 2. In this invention, the solubility of the soluble magnesium alloy is precisely controlled, adapting to the needs of different well conditions in oil and gas fields. The rationally proportioned Al, Zn, Cu, and Ni elements in the alloy form a multi-element corrosion micro-cell. Cu and Ni act as the cathode phase, accelerating the dissolution of Mg at the anode, while Al and Zn control the dissolution rate by adjusting the phase distribution, ensuring that the alloy's dissolution rate in a 3% KCl solution at room temperature remains stable at 15-20 mg / cm³. 2 / h. For shallow wells (depth < 3000m), this rate ensures the tool completely dissolves within 3-5 days after construction, avoiding interference with subsequent production; for deep wells (depth 3000-5000m), even in high-temperature well fluid environments of 60-120℃, the dissolution rate can be controlled at 30-50 mg / cm³. 2 / h, ensuring complete dissolution within 7-10 days. The stable dissolution performance of this invention can reduce the risk of tool failure by more than 60%, while eliminating the additional costs of traditional milling operations and improving the economics of oil and gas field development; 3. In this invention, a highly stable soluble magnesium alloy preparation system was constructed through strict control of parameters throughout the entire process, providing a reliable guarantee for large-scale industrial production. In the raw material stage, the control of metal purity of over 99.9% and the weighing accuracy of ±0.05wt% reduce the interference of impurities on alloy performance from the source. In the smelting stage, the use of a 0.5%SF6+99.5% CO2 protective atmosphere and alternating stirring process ensures that the alloy element distribution deviation is ≤0.1wt%, avoiding performance fluctuations caused by local component segregation. The holding temperature control of ±5℃ in the billet pretreatment ensures the consistency of the microstructure of each batch of billets. In the hot extrusion process, detailed control such as the die preheating temperature difference ≤5℃ and the billet transfer time ≤30s ensures that the dimensional accuracy of the extruded parts is controlled within ±0.2mm. The direct benefit of high stability is that the product qualification rate is increased to over 95% (compared to about 80% for traditional processes), and the performance deviation between different batches of products is ≤5%. At the same time, the standardization of process parameters (such as extrusion speed of 5-20mm / min and cooling wind speed of 10-15m / s) can be directly adapted to existing magnesium alloy extrusion production lines without the need for large-scale equipment modification. The annual production capacity of a single production line can reach 5,000-8,000 pieces, meeting the batch demand of oil and gas fields for soluble tools and promoting the transformation of soluble magnesium alloys from laboratory samples to industrial products. Attached Figure Description

[0017] Figure 1 This is a process flow diagram of the soluble magnesium alloy extrusion method in this invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] like Figure 1 As shown, this embodiment of the invention provides a soluble magnesium alloy, which contains the following components by mass percentage: Mg 85-95wt%, Al 3-8wt%, Zn 1-3wt%, Cu 0.5-2wt%, Ni 0.5-2wt%, and the purity of each component is ≥99.9%.

[0020] A method for extruding a soluble magnesium alloy, comprising the following steps: S1. Raw material preparation: Accurately weigh the pure metal of the soluble magnesium alloy using an electronic balance with an accuracy of 0.001g to ensure an error of ≤±0.05wt%; clean the surface oxide layer of the metal raw materials by removing obvious oxide scale with a wire brush and wiping the surface with a 95% ethanol solution until no stains remain to ensure elemental purity during smelting. S2. Melting and Casting: Melting is carried out in a protective atmosphere of 0.5% SF6 + 99.5% CO2. First, the crucible is preheated to 300-400℃ to remove moisture, then magnesium ingots are added, and the temperature is raised to 720-750℃ to completely melt them. Then, other metals are added in the order of Al, Zn, Cu, Ni. After all the metals have melted, the temperature is raised to 750-780℃ and stirred for 30-50 minutes to make the alloy composition uniform. After melting, the alloy liquid is allowed to stand for 10-15 minutes to remove air bubbles, and then poured into a low-carbon steel mold preheated to 150-200℃ at 680-720℃. The inner surface of the mold is pre-coated with a release agent. After casting, the alloy is allowed to cool naturally to room temperature in the air to form a cast alloy. S3. Billet Pretreatment: The as-cast alloy is machined into cylindrical billets with a diameter of 50-100mm and a length of 100-200mm using a lathe. After machining, the dimensions are measured with a micrometer to ensure that the dimensional accuracy is within ±0.1mm. The billets are placed in a box-type heat treatment furnace and heated to 380-420℃ at a rate of 5-10℃ / min. The temperature is held for 4-8 hours to achieve microstructure homogenization. During the holding process, the temperature fluctuation inside the furnace is controlled within ±5℃. After the holding is completed, the temperature is first reduced to 300℃ at a rate of 5℃ / min, and then cooled to 200℃ with the furnace to avoid internal stress caused by rapid cooling. S4. Hot Extrusion Molding: The billet is hot-extruded at a temperature of 380-420℃, with an extrusion ratio of 5-20 and an extrusion speed of 5-20 mm / min. Before extrusion, graphite lubricant is uniformly coated on the surface of the billet. This step includes several sub-steps. Among them, equipment and mold inspection must ensure that the performance parameters of the extruder are normal, mold preheating must ensure uniform temperature, billet transfer must be fast and temperature loss must be reduced, segmented extrusion must control the pressure and speed of different stages, cooling and straightening must ensure the dimensional accuracy of the profile, and mold maintenance can extend the mold service life. Through the coordinated operation of these sub-steps, high-performance soluble magnesium alloy extrusions are finally obtained.

[0021] In the raw material preparation step, the metal purity is 99.95%-99.98%, and vacuum packaging or inert gas protection is used during storage to prevent surface oxidation. For low-melting-point metals such as zinc and copper, they need to be pre-cut into small pieces ≤50mm to shorten the melting time.

[0022] In the melting and casting process, a silicon nitride stirring paddle is used, and the stirring is alternately at a speed of 30-50 r / min (forward for the first 10 minutes, reverse for the middle 20 minutes, and forward for the last 10 minutes) to ensure that the alloy element distribution deviation is ≤0.1wt%; during casting, an inclined pouring method is used, and the liquid flow rate is controlled at 0.5-1 m / s to avoid slag entrapment.

[0023] The equipment and mold inspection sub-steps for hot extrusion molding include: hydraulic system level ≥ 2 / 3 of the total volume of the hydraulic system tank, oil temperature 30-50℃ (preheating if below 30℃); mold core and mold sleeve clearance ≤ 0.05mm, extrusion rod reciprocating 3 times without load without jamming, stroke error ≤ ±0.5mm.

[0024] In the preheating sub-step of hot extrusion molding, the mold needs to be heated once every hour for 4 hours in advance according to the step temperature change of 100℃→200℃→300℃→extrusion temperature, with the working temperature difference ≤5℃, and the temperature data is recorded once every 10 minutes through thermocouples.

[0025] In the surface treatment sub-step of hot extrusion molding, graphite lubricant is mixed with anhydrous ethanol at a ratio of 1:3. At a viscosity of 50-80 mPa·s, it is sprayed at a distance of 20-30 cm using a 0.5 mm nozzle spray gun, with a coating thickness of 0.1-0.2 mm (local deviation ≤0.03 mm). It is then allowed to air dry for 10 minutes before use.

[0026] The segmented extrusion process of hot extrusion molding includes: a start-up stage where 50 mm is advanced at 30% of the rated pressure; a stabilization stage where the extrusion temperature deviation is maintained at 60%-80% of the rated pressure with a deviation of ≤±5℃; and a finish-up stage where the final 10 mm stroke is completed at 40% of the rated pressure. The entire process is monitored in real time by an infrared thermometer.

[0027] In the hot extrusion forming process, the billet transfer and loading steps are as follows: the time from the billet exiting the furnace to loading into the cylinder is ≤30s, and the temperature drop is ≤20℃; the deviation between the billet axis and the extrusion cylinder axis is ≤1mm during loading; after positioning and fixing, the end cap is closed to prevent eccentric deformation during the extrusion process.

[0028] The cooling, straightening, and die maintenance sub-steps of hot extrusion molding include: the extruded profile is air-cooled to below 150℃ at a wind speed of 10-15m / s, and then straightened by a multi-roller straightener with an initial reduction of 0.5mm each time until the straightness is ≤1mm / m. The initial reduction is 0.5mm, the second reduction is 0.25mm, and the third reduction is 0.125mm, for a total of 3 straightening operations. After extruding 5 blanks, the die working zone is cleaned and polished until Ra≤0.8μm. The die is replaced when the wear exceeds 0.1mm.

[0029] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0030] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A soluble magnesium alloy, characterized in that: The soluble magnesium alloy comprises the following components by mass percentage: Mg 85-95wt%, Al 3-8wt%, Zn 1-3wt%, Cu 0.5-2wt%, Ni 0.5-2wt%, and the purity of each component is ≥99.9%.

2. A method for extruding a soluble magnesium alloy, characterized in that: The extrusion method for the soluble magnesium alloy includes the following steps: S1. Raw material preparation: Accurately weigh the pure metal of the soluble magnesium alloy using an electronic balance with an accuracy of 0.001g to ensure an error of ≤±0.05wt%; clean the surface oxide layer of the metal raw materials by removing obvious oxide scale with a wire brush and wiping the surface with a 95% ethanol solution until no stains remain to ensure elemental purity during smelting. S2. Melting and Casting: Melting is carried out in a protective atmosphere of 0.5% SF6 + 99.5% CO2. First, the crucible is preheated to 300-400℃ to remove moisture, then magnesium ingots are added, and the temperature is raised to 720-750℃ to completely melt them. Then, other metals are added in the order of Al, Zn, Cu, Ni. After all the metals have melted, the temperature is raised to 750-780℃ and stirred for 30-50 minutes to make the alloy composition uniform. After melting, the alloy liquid is allowed to stand for 10-15 minutes to remove air bubbles, and then poured into a low-carbon steel mold preheated to 150-200℃ at 680-720℃. The inner surface of the mold is pre-coated with a release agent. After casting, the alloy is allowed to cool naturally to room temperature in the air to form a cast alloy. S3. Billet Pretreatment: The as-cast alloy is machined into cylindrical billets with a diameter of 50-100mm and a length of 100-200mm using a lathe. After machining, the dimensions are measured with a micrometer to ensure that the dimensional accuracy is within ±0.1mm. The billets are placed in a box-type heat treatment furnace and heated to 380-420℃ at a rate of 5-10℃ / min. The temperature is held for 4-8 hours to achieve microstructure homogenization. During the holding process, the temperature fluctuation inside the furnace is controlled within ±5℃. After the holding is completed, the temperature is first reduced to 300℃ at a rate of 5℃ / min, and then cooled to 200℃ with the furnace to avoid internal stress caused by rapid cooling. S4. Hot Extrusion Molding: The billet is hot-extruded at a temperature of 380-420℃, with an extrusion ratio of 5-20 and an extrusion speed of 5-20 mm / min. Before extrusion, graphite lubricant is uniformly coated on the surface of the billet. This step includes several sub-steps. Among them, equipment and mold inspection must ensure that the performance parameters of the extruder are normal, mold preheating must ensure uniform temperature, billet transfer must be fast and temperature loss must be reduced, segmented extrusion must control the pressure and speed of different stages, cooling and straightening must ensure the dimensional accuracy of the profile, and mold maintenance can extend the mold service life. Through the coordinated operation of these sub-steps, high-performance soluble magnesium alloy extrusions are finally obtained.

3. The method for extruding a soluble magnesium alloy according to claim 2, characterized in that: In the raw material preparation step, the metal purity is 99.95%-99.98%, and vacuum packaging or inert gas protection is used during storage to prevent surface oxidation. For low-melting-point metals such as zinc and copper, they need to be pre-cut into small pieces ≤50mm to shorten the melting time.

4. The method for extruding a soluble magnesium alloy according to claim 2, characterized in that: In the melting and casting process, a silicon nitride stirring paddle is used, and the stirring is alternately performed at a speed of 30-50 r / min to ensure that the alloy element distribution deviation is ≤0.1wt%; during casting, an inclined pouring method is used, and the liquid flow velocity is controlled at 0.5-1 m / s to avoid slag entrapment.

5. The method for extruding a soluble magnesium alloy according to claim 2, characterized in that: The equipment and mold inspection sub-steps for hot extrusion molding include: hydraulic system level ≥ 2 / 3 of the scale, oil temperature 30-50℃; mold core and mold sleeve clearance ≤ 0.05mm; extrusion rod reciprocates 3 times under no load without jamming, stroke error ≤ ±0.5mm.

6. The method for extruding a soluble magnesium alloy according to claim 2, characterized in that: In the preheating sub-step of the hot extrusion molding die, the die needs to be heated once every hour for 4 hours in advance according to the step temperature change of 100℃→200℃→300℃→extrusion temperature, with the working temperature difference ≤5℃, and the temperature data is recorded once every 10 minutes by thermocouple.

7. The method for extruding a soluble magnesium alloy according to claim 2, characterized in that: In the surface treatment sub-step of the hot extrusion forming blank, graphite lubricant is mixed with anhydrous ethanol at a ratio of 1:3, and sprayed at a distance of 20-30cm using a 0.5mm nozzle at a viscosity of 50-80mPa・s. The coating thickness is 0.1-0.2mm, and it is used after air drying for 10 minutes.

8. The method for extruding a soluble magnesium alloy according to claim 2, characterized in that: The segmented extrusion sub-steps of the hot extrusion molding include: a start-up stage where 50 mm is advanced at 30% of the rated pressure; a stabilization stage where the extrusion temperature deviation is maintained at 60%-80% of the rated pressure with a pressure of ≤±5℃; and a finish-up stage where the final 10 mm stroke is completed at 40% of the rated pressure. The entire process is monitored in real time by an infrared thermometer.

9. The method for extruding a soluble magnesium alloy according to claim 2, characterized in that: In the hot extrusion forming process, the billet transfer and loading steps are as follows: the time from the billet exiting the furnace to loading into the cylinder is ≤30s, and the temperature drop is ≤20℃; the deviation between the billet axis and the extrusion cylinder axis is ≤1mm during loading; after positioning and fixing, the end cap is closed to prevent eccentric deformation during the extrusion process.

10. The method for extruding a soluble magnesium alloy according to claim 2, characterized in that: The cooling, straightening, and die maintenance sub-steps of the hot extrusion molding process include: the extruded profile is air-cooled to below 150°C at a wind speed of 10-15 m / s, and the multi-roll straightener is used to gradually halve the initial reduction of 0.5 mm until the straightness is ≤1 mm / m; after extruding every 5 blanks, the die working zone is cleaned and polished until Ra≤0.8μm, and the die is replaced when the wear exceeds 0.1 mm.

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