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CN-122007193-A - Extrusion molding method of high-performance regenerated aluminum alloy profile suitable for anodic oxidation treatment

CN122007193ACN 122007193 ACN122007193 ACN 122007193ACN-122007193-A

Abstract

The invention relates to the technical field of metal pressure processing and discloses a high-performance regenerated aluminum alloy profile extrusion molding method suitable for anodic oxidation treatment, which comprises the steps of S1, preparing suspension containing strontium carbonate, potassium fluoborate and polyethylene wax, S2, coating the suspension on the surface of a regenerated aluminum alloy casting rod to form a solid precursor film, S3, pushing the heated casting rod into an extrusion cylinder for hot extrusion, utilizing friction heat of a sizing belt of an extrusion die to convert the potassium fluoborate into a semi-molten high-viscosity fluid phase, and utilizing shear stress applied by the sizing belt to drive the fluid phase to wrap strontium carbonate into the surface layer of the profile mechanically to induce solid-liquid interface reaction and in-situ spheroidizing impurity phase.

Inventors

  • LIU ZONGYI
  • ZHAO JUNLIN

Assignees

  • 湖南千源铝业有限公司

Dates

Publication Date
20260512
Application Date
20260331

Claims (10)

  1. 1. The extrusion molding method of the high-performance regenerated aluminum alloy section suitable for anodic oxidation treatment is characterized by comprising the following steps of: S1, preparing a shear rheological active medium, dispersing strontium carbonate powder, potassium fluoborate powder and polyethylene wax in an absolute ethyl alcohol solvent, and mixing to prepare a suspension, wherein the melting point of the potassium fluoborate powder is set to be higher than the extrusion outlet temperature of an aluminum alloy profile and lower than the friction peak temperature of a sizing belt of an extrusion die, and the melting point of the polyethylene wax is set to be lower than the extrusion outlet temperature, so as to construct a graded phase change thermodynamic system; S2, presetting the surface of a blank, coating the suspension on the cylindrical side surface of a regenerated aluminum alloy casting rod, and drying to remove an absolute ethyl alcohol solvent to form a solid precursor film; And S3, shearing rheological embedding extrusion, namely heating a regenerated aluminum alloy casting rod with a solid precursor film coated on the surface and pushing the regenerated aluminum alloy casting rod into an extrusion cylinder for hot extrusion, gasifying polyethylene wax in the solid precursor film by utilizing friction heat between a sizing bearing of the extrusion die and a metal flow and leaving a micropore channel in a film layer in the plastic deformation process of the sizing bearing of the extrusion die, simultaneously converting potassium fluoborate powder into a semi-molten high-viscosity fluid phase filling the micropore channel by utilizing friction heat, driving the semi-molten high-viscosity fluid phase to wrap hard strontium carbonate powder by utilizing tangential shearing stress applied by the sizing bearing of the extrusion die, overcoming the yield strength of a matrix, mechanically pressing the strontium carbonate powder into a grain boundary sliding belt on the surface layer of the aluminum alloy section, and inducing the strontium carbonate powder to generate solid-liquid interface reaction with the aluminum matrix at the pressing position by utilizing the local friction heat, blocking the anisotropic growth of needle-shaped iron-containing impurity phases in situ and spheroidizing the aluminum alloy section.
  2. 2. The extrusion molding method of high-performance secondary aluminum alloy profile suitable for anodic oxidation treatment according to claim 1, wherein in step S1, melting point of potassium fluoroborate powder Extrusion outlet temperature of aluminum alloy profile Peak temperature of friction with bearing of extrusion die The following thermodynamic constraint relation is satisfied: , wherein, Is between 480 degrees celsius and 510 degrees celsius, Is between 525 degrees celsius and 535 degrees celsius, The thermodynamic constraint relationship is used for ensuring that the potassium fluoborate is in a semi-molten high-viscosity state capable of transmitting hydrodynamic pressure at the moment when the strontium carbonate powder is mechanically pressed into a grain boundary sliding band.
  3. 3. The extrusion molding method of the high-performance regenerated aluminum alloy section suitable for anodic oxidation treatment according to claim 1, wherein in the step S1, the mass ratio of the strontium carbonate powder, the potassium fluoborate powder and the polyethylene wax is 4 to 2 to 1, the particle size D50 of the strontium carbonate powder is 2.0 to 5.0 microns, the particle size D50 is set to be larger than the grain boundary sliding band width of the aluminum alloy matrix and smaller than the grain size of the matrix, and the mechanical pinning effect is realized under the action of tangential shear stress.
  4. 4. The extrusion molding method of high-performance recycled aluminum alloy profile suitable for anodic oxidation treatment according to claim 1, wherein in step S3, the extrusion ratio of the shear rheological insert extrusion is set to be more than 30 to 1, the extrusion outlet speed is controlled to be 15 m/min to 25 m/min, and tangential shear stress of more than 40 mpa is generated in the bearing area of the extrusion die by maintaining the extrusion outlet speed for overcoming the yield strength of the surface layer of the aluminum alloy profile and pressing strontium carbonate powder into the surface layer metal matrix having a depth of 30 μm to 80 μm.
  5. 5. The extrusion molding method of the high-performance regenerated aluminum alloy section suitable for anodic oxidation treatment according to claim 1 is characterized in that in the step S3, a non-Newtonian fluid abrasive particle layer is built in a sizing area of an extrusion die by a semi-molten high-viscosity fluid phase, and the building process comprises the steps of forming a micropore channel in the non-Newtonian fluid abrasive particle layer by utilizing gasification decomposition of polyethylene wax when a regenerated aluminum alloy cast rod enters the sizing area of the extrusion die, filling the micropore channel by the semi-molten high-viscosity fluid phase and wrapping strontium carbonate powder to form a three-body friction system with a shear thickening characteristic, and converting sliding friction of the sizing area of the extrusion die into mixed friction containing a solid pinning phase under the normal pressure action of the sizing area of the extrusion die by the three-body friction system, and crushing a needle-shaped iron-containing impurity phase by utilizing mechanical energy generated by the mixed friction.
  6. 6. The extrusion molding method of high-performance regenerated aluminum alloy section suitable for anodic oxidation treatment according to claim 1, wherein in the step S2, the thickness of the solid precursor film is 10-30 microns, the solid precursor film is kept solid in the heating process of the step S3 until the solid precursor film enters a shearing deformation area of a bearing area of an extrusion die to undergo phase change, and the suspension further comprises hexagonal boron nitride powder, wherein the hexagonal boron nitride powder is used for filling microscopic pits on the surface of the aluminum alloy section after mechanical pressing of strontium carbonate powder is completed.
  7. 7. The extrusion molding method of high-performance recycled aluminum alloy profile suitable for anodic oxidation treatment according to claim 1, wherein in the step S1, the solid content of the suspension is 45-55%, the melting point of the polyethylene wax is 105-115 ℃, and the polyethylene wax is used as a film-forming binder for fixing strontium carbonate powder and potassium fluoborate powder after coating and drying.
  8. 8. The method according to claim 1, wherein in the step S3, the solid-liquid interface reaction comprises breaking the oxide film on the surface of the aluminum alloy profile by using potassium fluoborate under the action of local frictional heat to expose the fresh metal surface, and using the strontium atoms in the mechanically pressed strontium carbonate powder to form the molten aluminum alloy profile on the fresh metal surface and after the breaking AlFeSi phase is combined to form spherical or short rod shape Al (Sr) FeSi phase, spherical or short-rod form The Al (Sr) FeSi phase exhibits isotropic corrosion behaviour in the alkaline etching process of the subsequent anodic oxidation treatment.
  9. 9. The extrusion molding method of high-performance recycled aluminum alloy profile suitable for anodic oxidation treatment according to claim 1, wherein the length of the sizing belt of the extrusion die is set to be 6-10 mm for ensuring that the shearing residence time of the recycled aluminum alloy casting rod under the action of the semi-molten high-viscosity fluid phase meets the dynamic requirement of solid-liquid interface reaction, and the method further comprises the step of carrying out online quenching treatment on the extruded aluminum alloy profile after the step S3, wherein the cooling rate is higher than 200 ℃ per minute, and the method is used for freezing the microstructure after surface layer modification.
  10. 10. The extrusion molding method of high-performance recycled aluminum alloy profile suitable for anodic oxidation treatment according to claim 1, wherein the base material of the recycled aluminum alloy casting rod is a 6xxx series aluminum alloy added with waste aluminum, and the mass percentage of iron element contained in the waste aluminum is more than 0.2 percent, and the surface layer of the aluminum alloy profile is prepared by the method The average length-diameter ratio of the Al (Sr) FeSi phase is less than 2.0, and the surface glossiness deviation value of the aluminum alloy profile after the anodic oxidation treatment is less than 5 gloss units.

Description

Extrusion molding method of high-performance regenerated aluminum alloy profile suitable for anodic oxidation treatment Technical Field The invention relates to a high-performance regenerated aluminum alloy profile extrusion molding method suitable for anodic oxidation treatment, and belongs to the technical field of metal pressure processing. Background In the current industrial production of aluminum alloy sections, with the improvement of the recycling ratio of waste aluminum, the regenerated aluminum is difficult to remove impurity iron elements and tends to form needle-shaped sheetsAlFeSi phase, which is a brittle phase, is subjected to a subsequent anodic oxidation treatment procedure, particularly an alkaline etching pretreatment stage, and is subjected to anisotropic dissolution behavior due to potential difference with an aluminum matrix, so that the defects of stripe-shaped color difference and uneven glossiness distributed along the extrusion direction are extremely easy to be induced on the surface of a profile, the application of the field with high appearance quality requirements of the recycled aluminum is severely restricted, and in order to solve the problems, the prior mainstream technology generally adopts a strategy of prolonging the homogenizing annealing time of a casting rod or reducing the extrusion speed, and attempts to promote phase transformation through heat treatment or reduce surface tearing through low-speed rheology. However, in view of the actual production scene of modern industry pursuing high-efficiency extrusion, industrial-grade extrusion production lines generally require an outlet speed of more than 15m/min, meaning that metal flows through a die sizing, the time window in a critical forming zone is only in millisecond level, the modification of surface impurities cannot be completed by a traditional process depending on a thermal diffusion mechanism within such short contact time, the conventional B21C extrusion process generally follows antifriction and antiwear design philosophy, interface friction coefficients are reduced by nitriding a die working belt or applying a lubricant, macroscopic hot tearing is reduced, the service life of the die is prolonged, the pursuing of interface sliding is in a main flow transformation mode, the surface layer metal of a section bar in a severe plastic deformation zone is caused to lack of enough normal pressure and shearing and kneading action, so that the internal hard and brittle needle-like impurities are only subjected to simple orientation deflection or brittle fracture, the subsequent anodic oxidation process is aggravated, the same as the extrusion working condition of the section bar is influenced by simple optimization of alloy preparation or accumulated deformation quantity, for example, the patent application of an aluminum oxide preparation method for adding an aluminum oxide anode for a notebook computer shell of an authorized number CN118621164B is disclosed in China, the following the process of thin casting, the method is matched with high-pressure aluminum plate rolling quality and specific annealing is improved, the die life is reduced, the metal strip is subjected to be subjected to high-grade mechanical deformation, the defect is covered by the fact that the metal strip is subjected to high-grade deformation time, the process is subjected to high-grade mechanical deformation is covered by high-time, and the high-grade deformation is covered by the high-time window of the extrusion of the alloy is crushed by the alloy is subjected to high-grade compression, and the high-quality of the alloy is subjected to practical extrusion process is subjected to high-stage, so that the surface texture still restricts the high-quality application of the regenerated aluminum profile. Therefore, on the premise of maintaining the high-speed extrusion efficiency of the industrial grade, the limitation of microscopic rheological behavior of the surface of the traditional antifriction process is broken through, and a novel method for realizing spheroidization modification of the surface impurity phase by utilizing the instantaneous physical field of the extrusion process is constructed, so that the invention is the technical problem to be solved. Disclosure of Invention In order to solve the problems in the background technology, the technical scheme of the invention is as follows, a high-performance regenerated aluminum alloy profile extrusion molding method suitable for anodic oxidation treatment comprises the following steps: Step S1, preparing a shear rheological active medium, namely dispersing strontium carbonate powder, potassium fluoborate powder and polyethylene wax in an absolute ethyl alcohol solvent, and mixing to prepare a suspension, wherein the melting point of the potassium fluoborate powder is set to be higher than the extrusion outlet temperature of an aluminum alloy profile and lower than the friction peak temp