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CN-121972626-A - Hydraulic compact plastic forming process for magnesium alloy closed or semi-closed cavity piece, preparation method of anti-rheological salt core and magnesium alloy cavity product

CN121972626ACN 121972626 ACN121972626 ACN 121972626ACN-121972626-A

Abstract

The invention relates to a hydraulic compact plastic forming process of a magnesium alloy closed or semi-closed cavity piece, a preparation method of an anti-rheological salt core and a magnesium alloy cavity product. The hydraulic compaction plastic forming process of the magnesium alloy closed or semi-closed cavity piece comprises the steps of preparing an anti-rheological salt core, preparing magnesium alloy semi-solid slurry, adding magnesium alloy particles into a charging barrel, continuously heating and stirring until magnesium alloy semi-solid slurry with the solid content of 30% -50% is generated, assembling and positioning the anti-rheological salt core, fixing the anti-rheological salt core at the central part of an injection molding cavity of an injection mold, closing the injection molding cavity, performing semi-solid injection molding, injecting the semi-solid slurry into the injection molding cavity, performing pressure maintaining after filling the injection molding cavity, cooling and demolding after the pressure maintaining, obtaining a magnesium alloy closed or semi-closed cavity blank, and dissolving the salt core to obtain a magnesium alloy cavity product. The invention ensures the precision and stability of the cavity structure of the magnesium alloy cavity product.

Inventors

  • HUANG HUA
  • YU ZHIJUN

Assignees

  • 兰溪市捷克运动器材制造有限公司

Dates

Publication Date
20260505
Application Date
20260408

Claims (13)

  1. 1. A process for hydroforming a closed/semi-closed magnesium alloy cavity member, comprising the steps of: S1, preparing an anti-rheological salt core, wherein the anti-rheological salt core comprises, by mass, 85% -98% of NaCl, 0% -10% of MgCl 2 and 2% -5% of Na 3535; s2, preparing magnesium alloy semisolid slurry, namely adding a magnesium alloy raw material into a charging barrel, continuously heating and stirring until the magnesium alloy semisolid slurry with the solid content of 30% -50% is generated; s3, assembling and positioning an anti-rheological salt core, namely fixing the anti-rheological salt core at the central part of an injection molding cavity of an injection mold, closing the injection molding cavity and preheating; s4, semi-solid injection molding, namely injecting the semi-solid slurry into an injection molding cavity, maintaining pressure after filling the injection molding cavity, and cooling and demolding after maintaining the pressure to obtain a magnesium alloy closed/semi-closed cavity blank; s5, dissolving the salt core to obtain a magnesium alloy cavity product, namely immersing the blank into deionized water to dissolve the anti-rheological salt core to obtain the magnesium alloy cavity product.
  2. 2. The process for hydroforming a closed/semi-closed cavity member of magnesium alloy according to claim 1, wherein the density of the anti-rheological salt core is not less than 2.0 g/cm3 and the compressive strength is not less than 20MPa.
  3. 3. The process for hydroforming a closed/semi-closed cavity member according to claim 1, wherein the material of the magnesium alloy raw material is one or a combination of more of AM60 magnesium alloy, AZ91 magnesium alloy, AZ31 magnesium alloy, ZE41 magnesium alloy, WE43 magnesium alloy.
  4. 4. The process for hydroforming a closed/semi-closed cavity member of magnesium alloy according to claim 1, wherein in the step S2, the heating temperature is 570 ℃ to 610 ℃ and the stirring speed is 100 r/min.
  5. 5. The process for hydroforming a closed/semi-closed cavity member of magnesium alloy according to claim 1, wherein the preheating temperature in the step S3 is 180 ℃ to 220 ℃.
  6. 6. The process for hydraulically tight plastic forming of a closed/semi-closed cavity piece of magnesium alloy according to claim 1, wherein in the step S4, the pressure maintaining environment is 10 MPa-20 MPa, the pressure maintaining time is 1S-5S, the process is used for compensating cooling shrinkage of magnesium alloy, the cooling temperature is 80-100 ℃ for demoulding, the injection speed is 1 m/S-3 m/S, and the injection pressure is 5 MPa-15 MPa.
  7. 7. The process for hydraulically tight plastic forming of a closed/semi-closed cavity piece of magnesium alloy according to claim 1, wherein in the step S4, the injection device is a semi-solid die casting machine of magnesium alloy, and the discharge end of the charging barrel is communicated with the feed end of the semi-solid die casting machine of magnesium alloy.
  8. 8. The process for hydraulically tight plastic forming of a magnesium alloy closed/semi-closed cavity piece according to claim 1, wherein in the step S5, deionized water is at a temperature of 70 ℃ to 90 ℃ and soaking time is 15min to 25min, the volume ratio of deionized water to the blank is not less than 5:1, and ultrasonic cleaning or high-pressure water cleaning is used to accelerate salt core dissolution when the blank is immersed in the deionized water; Wherein the ultrasonic cleaning temperature is 160-190 ℃, the cleaning time is 15-25 min, the high-pressure water cleaning pressure is 0.3-0.5 MPa, and the cleaning time is 10-15 min.
  9. 9. The process for hydroforming a closed/semi-closed cavity member of magnesium alloy according to claim 1, wherein after said step S5, the magnesium alloy cavity product is subjected to heat treatment and surface treatment; the heat treatment equipment is an aging furnace, the heat treatment temperature is 160-190 ℃, the heat treatment time is 1.5-2.5 h, the surface treatment equipment is a sand blasting machine, and the sand blasting granularity is 80-120 meshes.
  10. 10. A method for preparing an anti-rheological salt core, wherein the anti-rheological salt core is used for the hydraulic compaction plastic forming process of the magnesium alloy closed/semi-closed cavity piece according to any one of claims 1 to 9, and the method comprises the following steps: S11, designing a salt core mold cavity according to a closed/semi-closed mold cavity structure of a magnesium alloy mold cavity product; S12, uniformly mixing the raw materials according to the mass percentage of 85% -98% of NaCl, 0% -10% of MgCl 2 and 2% -5% of Na 2 SiO 3 to prepare a mixed material; s13, injecting the mixed material into a salt core mold cavity for compression molding to obtain a first molded body; s14, carrying out cold isostatic pressing on the first molded body to obtain a second molded body, wherein the pressure of the cold isostatic pressing is 100-200 MPa; S15, drying the second molded body to remove water to obtain the anti-rheological salt core, wherein the drying time is 3-5 h, and the drying temperature is 140-160 ℃.
  11. 11. A magnesium alloy cavity product, characterized in that it is produced by a hydraulic compaction plastic forming process of a magnesium alloy closed/semi-closed cavity piece according to any one of claims 1-9.
  12. 12. The magnesium alloy cavity product of claim 11, wherein the structure comprises: A main supporting framework distributed along the stress direction of the alloy closed/semi-closed cavity piece, And a thin-walled packing layer overlying the main support frame to form a complex hollow profile.
  13. 13. The magnesium alloy cavity product of claim 12, wherein the thin-walled filler layer has a thickness of 0.8mm to 1.2mm.

Description

Hydraulic compact plastic forming process for magnesium alloy closed or semi-closed cavity piece, preparation method of anti-rheological salt core and magnesium alloy cavity product Technical Field The invention relates to the technical field of magnesium alloy plastic forming, in particular to a hydraulic compact plastic forming process of a magnesium alloy closed or semi-closed cavity piece, a preparation method of an anti-rheological salt core and a magnesium alloy cavity product. Background In the processing and manufacturing of closed or semi-closed cavity products, the cooperative optimization of light weight and mechanical properties is a core requirement. Because of its excellent specific strength characteristics, magnesium alloy materials are widely used in a wide range of fields such as automobiles, aerospace, military industry, medical equipment, electronic products, and the like. However, the manufacturing process of conventional magnesium alloy closed or semi-closed components presents significant challenges. Firstly, in the forming method of a magnesium alloy closed or semi-closed component, the prior art relies on machining and hollowing to construct an internal cavity structure, and then the welding process is assisted to finish the processing of the component. However, this manufacturing method not only results in complex process steps and prolonged production cycle, but also tends to create heat affected zone defects or stress concentrations in the weld area, significantly impairing the overall structural integrity and load carrying capacity of the product. Meanwhile, a manufacturing mode of core pulling processing auxiliary semi-solid die casting is also appeared in the market at present, such as a die for forming an aluminum alloy 5G communication base station chassis shell piece through semi-solid rheocasting and a use method thereof, wherein the die is disclosed in China (bulletin) No. CN 112296309B. However, this manufacturing method is only suitable for semi-closed member products in which the member has a large enough opening to accommodate the core back mold, and this condition is not satisfied for most closed or semi-closed members, and true integral molding cannot be achieved. Secondly, when the salt core is adopted for auxiliary molding, the common salt core bears the dual effects of high-temperature environment and high-pressure rheological stress in the magnesium alloy semi-solid injection molding process, the material strength is insufficient, plastic deformation, structural collapse or premature dissolution are easy to occur, the shape of the hollow cavity is unstable, and the molding failure rate is high. In addition, the preparation of the traditional semi-solid slurry requires additional pretreatment steps, including precise control of the solid phase rate and temperature, increases the process complexity and equipment cost, and restricts the improvement of the production efficiency and the product quality. Therefore, we propose a hydraulic compact plastic forming process for a magnesium alloy closed or semi-closed cavity piece, a preparation method for an anti-rheological salt core and a magnesium alloy cavity product. Disclosure of Invention The application provides a hydraulic compact plastic forming process of a magnesium alloy closed or semi-closed cavity piece, a preparation method of an anti-rheological salt core and a magnesium alloy cavity product, which at least solve the problems that three pain points exist in the existing preparation process, namely, a step-by-step forming mode of welding or machining hollowing is complex in process, easy to generate defects and difficult to integrally form, a salt core is easy to lose efficacy under high temperature and high pressure during auxiliary forming of the salt core, extra pretreatment is needed for preparing semi-solid slurry, the complexity and cost of the process are improved, and the quality and the production efficiency of the magnesium alloy cavity product are finally restricted. In a first aspect, the application provides a process for hydroforming a magnesium alloy closed or semi-closed cavity piece, comprising the steps of: S1, preparing an anti-rheological salt core, wherein the anti-rheological salt core comprises, by mass, 85% -98% of NaCl, 0% -10% of MgCl 2 and 2% -5% of Na 3535; From the above, in step S1, the anti-rheological salt core is a salt-based core body capable of maintaining stable structure, difficult deformation or collapse in a high-temperature and high-pressure semi-solid injection molding environment, and has the main functions of supporting the hollow structure of a closed or semi-closed cavity in the shaping process of a magnesium alloy cavity product, and removing the hollow structure by dissolution after shaping, thereby realizing the integrated manufacturing of the closed or semi-closed cavity product. S2, preparing magnesium alloy semisolid slurry, namely adding a magnesium alloy r