Extrusion casting method for improving precision of thin-wall metal part
By combining induction coil heating with punch pressure in a squeeze casting method, along with solution treatment and aging treatment, the flowability and precision problems of thin-walled metal parts have been solved, and high-precision thin-walled metal parts have been manufactured.
Patent Information
- Application Number
- CN202511462206.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-14
- Publication Date
- 2026-01-13
AI Technical Summary
When extruding thin-walled metal parts, problems such as insufficient fluidity of molten metal, uneven wall thickness due to excessively rapid solidification, surface porosity, or slag inclusions may occur, affecting the precision and quality of the parts.
By combining induction coil heating with punch pressurization, and by gradually controlling the extrusion pressure and induction coil power, the alloy liquid is ensured to have good fluidity during the extrusion process. Furthermore, the grain size is stabilized through solution treatment and aging treatment, thereby improving the precision of the parts.
It effectively reduces internal defects, improves the surface quality and precision of thin-walled metal parts, and ensures the dimensional stability and mechanical properties of the parts.
Smart Images
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Abstract
Description
Technical Field
[0001] This invention relates to the field of extrusion casting technology, specifically to an extrusion casting method for improving the precision of thin-walled metal parts. Background Technology
[0002] Squeeze casting is a technique that solidifies molten metal under direct extrusion pressure. Specifically, liquid or semi-solid metal is injected into a mold cavity and mechanical pressure is applied, causing the molten metal to fill, crystallize, and plastically deform under high pressure. Castings produced by squeeze casting have advantages such as dense structure and high mechanical properties.
[0003] Currently, when using squeeze casting to prepare thin-walled metal parts, due to the large surface area of thin-walled metal parts, insufficient fluidity of the molten metal or too rapid solidification can easily lead to cold shuts or incomplete filling, resulting in uneven wall thickness of thin-walled metal parts. Furthermore, thin-walled metal parts are prone to surface porosity or inclusions, resulting in poor surface quality. Summary of the Invention
[0004] To address the aforementioned problems, this invention provides a squeeze casting method for improving the precision of thin-walled metal parts.
[0005] The technical solution of this invention is: a squeeze casting method for improving the precision of thin-walled metal parts, comprising the following steps: S1. Heat the aluminum alloy ingot to 730~780℃, and obtain the alloy liquid after the aluminum alloy ingot is completely melted. S2. Preheat the mold, then spray the mold release agent into the mold. After the mold release agent is sprayed, pour the alloy liquid into the mold. S3. Start the die-casting machine and let the punch enter the mold to extrude the alloy liquid. The initial extrusion pressure is 20~30MPa and the extrusion speed is 50~100mm / s. After the punch and the mold are closed, the extrusion pressure begins to gradually increase. At the same time, the mold is heated by an induction coil. The initial power of the induction coil is 6~8kW and the frequency is 8~12kHz. When the extrusion pressure is <50MPa, the extrusion pressure is gradually increased at a rate of 10~20MPa / min, and the power of the induction coil is gradually increased at a rate of 1~2kW / min. When 50MPa≤extrusion pressure<80MPa, the power of the induction coil begins to remain constant, and the extrusion pressure gradually increases at a rate of 8~12MPa / min. When the extrusion pressure is ≥80MPa, the extrusion pressure is gradually increased at a rate of 2~4MPa / min, and the induction coil power is gradually decreased at a rate of 3~5kW / min until the induction coil is completely shut off, and the pressure is maintained for 1~3min. S4. Depressurize and demold to obtain the workpiece. Perform solution treatment and aging treatment on the workpiece to obtain thin-walled metal parts.
[0006] Explanation: The above-mentioned squeeze casting method uses induction coil heating and punch pressure to ensure the fluidity of the alloy liquid during the extrusion process to achieve sufficient feeding, reduce internal defects in thin-walled metal parts, and then gradually increase the extrusion pressure to refine the grains of thin-walled metal parts, stabilize the dimensions of thin-walled metal parts, and improve the precision of thin-walled metal parts.
[0007] Further, in step S1, the composition of the aluminum alloy ingot, by mass percentage, includes: Si 8~12%, Cu 1~3%, Mg 0.5~3%, Mn 0.4~0.8%, Fe 0.1~0.3%, RE 0.1~0.3%, and the remainder is Al.
[0008] Note: The aluminum alloy ingots with the above composition have good fluidity and mechanical properties, which can fully fill the cavity in the mold and ensure the surface quality and strength of thin-walled metal parts.
[0009] Furthermore, in step S2, the preheating temperature is 430~460℃.
[0010] Note: Preheating can prevent a large temperature difference when the molten alloy comes into contact with the mold, ensuring the fluidity of the molten alloy and preventing it from solidifying rapidly.
[0011] Furthermore, in step S2, the spraying amount of the release agent is 6~10 g / m³. 2 .
[0012] Note: Limiting the amount of release agent sprayed ensures that the release agent can fully cover the inside of the mold and avoids excessive accumulation of release agent.
[0013] Further, in step S2, the components of the release agent, by mass percentage, include: 15-25% methyl silicone oil, 4-6% alkylphenol polyoxyethylene ether, 0.5-2% triethanolamine, 3-5% aluminum silicate, and the remainder is water.
[0014] Note: The above-mentioned mold release agent can form a film layer inside the mold, ensuring the demolding effect, and can also promote the heat transfer effect inside the mold, so that the heat can be evenly transferred to the alloy liquid when the induction coil is heated.
[0015] Furthermore, in step S3, the inner diameter of the induction coil is 15-30 mm larger than the outer diameter of the mold.
[0016] Note: Limiting the inner diameter of the induction coil ensures a uniform distribution of the magnetic field outside the mold, avoids excessive temperature differences on the mold surface, and prevents direct contact between the induction coil and the mold, which could damage the mold.
[0017] Further, in step S4, the solution treatment method is as follows: the workpiece is kept at 460~520℃ for 3~5 hours, and then the workpiece is placed in water for cooling.
[0018] Explanation: Solution treatment can fully dissolve the strengthening phase in aluminum alloy into the aluminum matrix, thereby eliminating grain boundary segregation and improving the strength and toughness of thin-walled metal parts.
[0019] Further, in step S4, the aging treatment method is as follows: the workpiece is kept at 140~170℃ for 8~12h, and then removed from the furnace and air-cooled.
[0020] Note: Aging treatment can eliminate residual stress generated during casting, reduce deformation of thin-walled metal parts, and stabilize the reduction of the size of thin-walled metal parts.
[0021] The beneficial effects of this invention are: (1) The present invention uses the combination of induction coil heating and punch pressure to ensure the fluidity of the alloy liquid during the extrusion process so as to fully compensate for the shrinkage, reduce the internal defects of thin-walled metal parts, and then gradually increase the extrusion pressure to refine the grains of thin-walled metal parts, stabilize the size of thin-walled metal parts, and improve the precision of thin-walled metal parts.
[0022] (2) The release agent of the present invention can form a film layer in the mold to ensure the release effect and can promote the heat transfer effect in the mold, so that the heat can be evenly transferred to the alloy liquid when the induction coil is heated. Detailed Implementation
[0023] To further illustrate the methods and effects of this invention, the technical solution of this invention will be clearly and completely described below in conjunction with experiments.
[0024] Example 1: A squeeze casting method for improving the precision of thin-walled metal parts, comprising the following steps: S1. Heat the aluminum alloy ingot to 750°C until the aluminum alloy ingot is completely melted to obtain the alloy liquid. The composition of the aluminum alloy ingot, by mass percentage, includes: Si 10%, Cu 2%, Mg 2%, Mn 0.6%, Fe 0.2%, RE 0.2%, with the remainder being Al; RE is cerium. S2. Preheat the mold, then spray the mold release agent into the mold. After the mold release agent is sprayed, pour the alloy liquid into the mold. The preheating temperature is 440℃, and the amount of release agent sprayed is 8g / m³. 2 The mold release agent comprises, by weight percentage: 20% methyl silicone oil, 5% alkylphenol polyoxyethylene ether, 1% triethanolamine, 4% aluminum silicate, and the remainder is water. S3. Start the die-casting machine and let the punch enter the mold to extrude the alloy liquid. The initial extrusion pressure is 25MPa and the extrusion speed is 80mm / s. After the punch and mold are closed, the extrusion pressure begins to gradually increase. At the same time, the mold is heated by an induction coil. The initial power of the induction coil is 7kW and the frequency is 10kHz. The inner diameter of the induction coil is 20mm larger than the outer diameter of the mold. When the extrusion pressure is <50MPa, the extrusion pressure is gradually increased at a rate of 15MPa / min, and the power of the induction coil is gradually increased at a rate of 1.5kW / min. When 50MPa≤extrusion pressure<80MPa, the power of the induction coil begins to remain constant, and the extrusion pressure gradually increases at a rate of 10MPa / min. When the extrusion pressure is ≥80MPa, the extrusion pressure is gradually increased at a rate of 3MPa / min, and the induction coil power is gradually decreased at a rate of 4kW / min until the induction coil is completely turned off, and then the pressure is maintained for 2min. S4. Depressurize and demold to obtain the workpiece. Perform solution treatment and aging treatment on the workpiece to obtain thin-walled metal parts. The solution treatment method is as follows: the workpiece is kept at 480℃ for 4 hours, and then the workpiece is placed in water for cooling; the aging treatment method is as follows: the workpiece is kept at 150℃ for 10 hours, and then removed from the furnace and air-cooled; the thin-walled metal part prepared in this embodiment is a thin-walled cylinder with a wall thickness of 4mm.
[0025] Example 2: This example is basically the same as Example 1, except that the composition of the aluminum alloy ingot by mass percentage includes: Si 8%, Cu 1%, Mg 0.5%, Mn 0.4%, Fe 0.1%, RE 0.1%, and the remainder is Al.
[0026] Example 3: This example is basically the same as Example 1, except that the composition of the aluminum alloy ingot by mass percentage includes: Si 12%, Cu 3%, Mg 3%, Mn 0.8%, Fe 0.3%, RE 0.3%, and the remainder is Al.
[0027] Example 4: This example is basically the same as Example 1, except that the amount of release agent sprayed is 6g / m². 2 .
[0028] Example 5: This example is basically the same as Example 1, except that the amount of release agent sprayed is 10g / m². 2 .
[0029] Example 6: This example is basically the same as Example 1, except that the composition of the release agent by mass percentage includes: 15% methyl silicone oil, 4% alkylphenol polyoxyethylene ether, 0.5% triethanolamine, 3% aluminum silicate, and the remainder is water.
[0030] Example 7: This example is basically the same as Example 1, except that the composition of the release agent by mass percentage includes: 25% methyl silicone oil, 6% alkylphenol polyoxyethylene ether, 2% triethanolamine, 5% aluminum silicate, and the remainder is water.
[0031] Example 8: This example is basically the same as Example 1, except that the initial extrusion pressure is 20MPa and the extrusion speed is 50mm / s.
[0032] Example 9: This example is basically the same as Example 1, except that the initial extrusion pressure is 30MPa and the extrusion speed is 100mm / s.
[0033] Example 10: This example is basically the same as Example 1, except that the initial power of the induction coil is 6kW and the frequency is 8kHz.
[0034] Example 11: This example is basically the same as Example 1, except that the initial power of the induction coil is 8kW and the frequency is 12kHz.
[0035] Example 12: This example is basically the same as Example 1, except that when the extrusion pressure is <50MPa, the extrusion pressure is gradually increased at a rate of 10MPa / min, and the power of the induction coil is gradually increased at a rate of 1kW / min.
[0036] Example 13: This example is basically the same as Example 1, except that when the extrusion pressure is <50MPa, the extrusion pressure is gradually increased at a rate of 20MPa / min, and the power of the induction coil is gradually increased at a rate of 2kW / min.
[0037] Example 14: This example is basically the same as Example 1, except that when 50MPa≤extrusion pressure<80MPa, the power of the induction coil begins to remain constant, and the extrusion pressure gradually increases at a rate of 8MPa / min.
[0038] Example 15: This example is basically the same as Example 1, except that when 50MPa≤extrusion pressure<80MPa, the power of the induction coil begins to remain constant, and the extrusion pressure gradually increases at a rate of 12MPa / min.
[0039] Example 16: This example is basically the same as Example 1, except that when the extrusion pressure is ≥80MPa, the extrusion pressure is gradually increased at a rate of 2MPa / min, and the induction coil power is gradually decreased at a rate of 3kW / min.
[0040] Example 17: This example is basically the same as Example 1, except that when the extrusion pressure is ≥80MPa, the extrusion pressure is gradually increased at a rate of 4MPa / min, and the induction coil power is gradually decreased at a rate of 5kW / min.
[0041] Comparative Example 1: Referring to Example 1, deionized water was used to replace aluminum silicate in the release agent.
[0042] Comparative Example 2: Referring to Example 1, the mold was not heated using an induction coil.
[0043] Comparative Example 3: Referring to Example 1, the power of the induction coil is kept constant at 7kW.
[0044] Experimental Example: To investigate the influence of various preparation parameters on the precision of thin-walled metal parts, wall thickness tests were conducted at ten points on the thin-walled metal parts prepared in each embodiment. The maximum difference between the actual wall thickness and the required wall thickness was calculated. The surface roughness of the thin-walled metal parts prepared in each embodiment before finishing was also tested. The specific investigation is as follows: 1. Investigating the influence of aluminum alloy ingot composition on the precision of thin-walled metal parts. Using Examples 1-3 as experimental comparisons, the accuracy of thin-walled metal parts with different compositions of aluminum alloy ingots is shown in Table 1 below: Table 1. Precision of thin-walled metal parts with different compositions of aluminum alloy ingots.
[0045] As shown in Table 1, compared with Examples 1, 2 and 3, the thin-walled metal parts of Example 1 have the smallest wall thickness difference and surface roughness, indicating that the thin-walled metal parts of Example 1 have the highest precision. Therefore, the aluminum alloy ingot composition selected in Example 1 is optimal.
[0046] 2. Investigate the effects of mold release agent composition and spraying amount on the precision of thin-walled metal parts. Using Examples 1, 4-7 and Comparative Example 1 as experimental comparisons, the accuracy of thin-walled metal parts under different release agent compositions and spray amounts is shown in Table 2 below: Table 2 Precision of thin-walled metal parts under different mold release agent compositions and spray amounts
[0047] As shown in Table 2, compared with Examples 1, 4 and 5, the thin-walled metal parts of Example 1 have the smallest wall thickness difference and surface roughness, indicating that the thin-walled metal parts of Example 1 have the highest precision. This may be because the amount of release agent sprayed in Example 1 is moderate and no large temperature occurs in the mold. Therefore, the amount of release agent sprayed in Example 1 is optimal. Compared with Examples 1, 6, and 7: The thin-walled metal parts of Example 1 have the smallest wall thickness difference and surface roughness, indicating that the thin-walled metal parts of Example 1 have the highest precision. This may be because the release agent composition selected in Example 1 has the best release effect. Therefore, the release agent composition selected in Example 1 is the optimal. Compared with Comparative Example 1, in Example 1, the surface roughness of thin-walled metal parts increased significantly after replacing aluminum silicate in the mold release agent with deionized water. This may be because aluminum silicate can improve the heat transfer effect of the mold. Therefore, the mold release agent composition selected in Example 1 is better.
[0048] 3. Investigate the influence of initial extrusion parameters on the accuracy of thin-walled metal parts. Using Examples 1, 8, and 9 as experimental comparisons, the accuracy of thin-walled metal parts under different initial extrusion parameters is shown in Table 3 below: Table 3. Precision of thin-walled metal parts under different initial extrusion parameters
[0049] As shown in Table 3, compared with Examples 1, 8, and 9, the thin-walled metal parts of Example 1 have the smallest wall thickness difference and surface roughness, indicating that the thin-walled metal parts of Example 1 have the highest precision. This may be because the alloy liquid can fully fill the mold cavity under the initial extrusion parameters selected in Example 1, so the initial extrusion parameters selected in Example 1 are optimal.
[0050] 4. Investigate the influence of initial parameters of induction coils on the accuracy of thin-walled metal parts. Using Examples 1, 10, 11 and Comparative Example 2 as experimental comparisons, the accuracy of thin-walled metal parts under different initial parameters of the induction coil is shown in Table 4 below: Table 4. Accuracy of thin-walled metal parts under different initial parameters of induction coil
[0051] As shown in Table 4, compared with Examples 1, 10 and 11, the thin-walled metal parts of Example 1 have the smallest wall thickness difference and surface roughness, indicating that the thin-walled metal parts of Example 1 have the highest precision. This may be because the alloy liquid has the best fluidity under the initial parameters of the induction coil selected in Example 1, which can fully compensate for shrinkage. Therefore, the initial parameters of the induction coil selected in Example 1 are optimal. Compared with Comparative Example 2, Example 1 shows that the precision of thin-walled metal parts decreased significantly after heating the mold without using an induction coil. This may be because the alloy liquid failed to fully compensate for the shrinkage, resulting in more defects in the thin-walled metal parts. Therefore, the squeeze casting method selected in Example 1 is the optimal one.
[0052] 5. Investigate the influence of extrusion pressure and induction coil power variations on the accuracy of thin-walled metal parts. Using Examples 1, 12-17, and Comparative Example 3 as experimental comparisons, the accuracy of thin-walled metal parts under different parameters of extrusion pressure and induction coil power is shown in Table 5 below: Table 5. Precision of thin-walled metal parts under different parameters of extrusion pressure and induction coil power.
[0053] As shown in Table 5, compared with Examples 1 and 12-17, the thin-walled metal parts of Example 1 have the smallest wall thickness difference and surface roughness, indicating that the thin-walled metal parts of Example 1 have the highest precision. This may be because the alloy liquid can fully fill the cavity and perform feeding under the extrusion pressure and induction coil power variation parameters selected in Example 1. Therefore, the extrusion pressure and induction coil power variation parameters selected in Example 1 are optimal. Compared with Comparative Example 3, Example 1 shows that after the power of the induction coil is kept constant, the precision of the thin-walled metal parts decreases significantly. This may be because solidification and crystallization cannot occur during the extrusion of the alloy liquid, resulting in coarse grains in the thin-walled metal parts. Therefore, the extrusion casting method selected in Example 1 is optimal.
Claims
1. A squeeze casting method for improving the precision of thin-walled metal parts, characterized in that, Includes the following steps: S1. Heat the aluminum alloy ingot to 730~780℃, and obtain the alloy liquid after the aluminum alloy ingot is completely melted. S2. Preheat the mold, then spray the mold release agent into the mold. After the mold release agent is sprayed, pour the alloy liquid into the mold. S3. Start the die-casting machine and let the punch enter the mold to extrude the alloy liquid. The initial extrusion pressure is 20~30MPa and the extrusion speed is 50~100mm / s. After the punch and the mold are closed, the extrusion pressure begins to gradually increase. At the same time, the mold is heated by an induction coil. The initial power of the induction coil is 6~8kW and the frequency is 8~12kHz. When the extrusion pressure is <50MPa, the extrusion pressure is gradually increased at a rate of 10~20MPa / min, and the power of the induction coil is gradually increased at a rate of 1~2kW / min. When 50MPa≤extrusion pressure<80MPa, the power of the induction coil begins to remain constant, and the extrusion pressure gradually increases at a rate of 8~12MPa / min. When the extrusion pressure is ≥80MPa, the extrusion pressure is gradually increased at a rate of 2~4MPa / min, and the induction coil power is gradually decreased at a rate of 3~5kW / min until the induction coil is completely shut off, and the pressure is maintained for 1~3min. S4. Depressurize and demold to obtain the workpiece. Perform solution treatment and aging treatment on the workpiece to obtain thin-walled metal parts.
2. The extrusion casting method for improving the precision of thin-walled metal parts according to claim 1, characterized in that, In step S1, the composition of the aluminum alloy ingot, by mass percentage, includes: Si 8~12%, Cu 1~3%, Mg 0.5~3%, Mn 0.4~0.8%, Fe 0.1~0.3%, RE 0.1~0.3%, and the remainder is Al.
3. The extrusion casting method for improving the precision of thin-walled metal parts according to claim 1, characterized in that, In step S2, the preheating temperature is 430~460℃.
4. The extrusion casting method for improving the precision of thin-walled metal parts according to claim 1, characterized in that, In step S2, the spraying amount of the release agent is 6~10 g / m³. 2 .
5. The extrusion casting method for improving the precision of thin-walled metal parts according to claim 1, characterized in that, In step S2, the mold release agent comprises, by mass percentage: 15-25% methyl silicone oil, 4-6% alkylphenol polyoxyethylene ether, 0.5-2% triethanolamine, 3-5% aluminum silicate, and the remainder is water.
6. The extrusion casting method for improving the precision of thin-walled metal parts according to claim 1, characterized in that, In step S3, the inner diameter of the induction coil is 15-30 mm larger than the outer diameter of the mold.
7. The extrusion casting method for improving the precision of thin-walled metal parts according to claim 1, characterized in that, In step S4, the solution treatment method is as follows: the workpiece is kept at 460~520℃ for 3~5 hours, and then the workpiece is placed in water for cooling.
8. The extrusion casting method for improving the precision of thin-walled metal parts according to claim 1, characterized in that, In step S4, the aging treatment method is as follows: the workpiece is kept at 140~170℃ for 8~12h, and then removed from the furnace and air-cooled.