Preparation method of aluminum alloy extruded profile

Abstract

The invention belongs to the technical field of non-ferrous metal material preparation, and particularly relates to a preparation method of an aluminum alloy extruded profile, which comprises the following steps: smelting and casting raw material components of the aluminum alloy extruded profile to obtain a cast ingot, and then carrying out homogenization treatment, three-way high-temperature upsetting and drawing, high-temperature annealing, cryogenic three-way compression, high-temperature extrusion, cooling and aging treatment to obtain the aluminum alloy extruded profile. An aluminum alloy extrusion profile is obtained; the temperature of three-way high-temperature upsetting and drawing ranges from 500 DEG C to 560 DEG C, the temperature of high-temperature annealing ranges from 540 DEG C to 580 DEG C, the temperature of cryogenic three-way compression ranges from-180 DEG C to-150 DEG C, and the temperature of high-temperature extrusion ranges from 500 DEG C to 540 DEG C; the strength and the ductility of the aluminum alloy extruded profile are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of non-ferrous metal material preparation, and particularly relates to a preparation method of an aluminum alloy extrusion profile. Background Art

[0002] The Al-Mg-Si-Cu alloy has relatively high contents of Si and Cu elements, which makes its tensile strength increase by about 20% compared with the traditional 6061 aluminum alloy. In addition, the contents of elements such as Fe, Zn, and Mn are also strictly controlled. Therefore, it has excellent machining performance, brightness, and surface treatment performance while having good mechanical properties, and is currently widely used in the field of electronic 3C products. However, in actual production, if the forming process is not strictly controlled, the Al-Mg-Si-Cu alloy extruded material is prone to problems such as coarse grain structure and low mechanical properties, which will further cause the electronic 3C products to fail to meet the design index requirements, and even require rework or scrapping.

[0003] The high-strength and high-elongation Al-Mg-Si-Cu alloy extruded material has strict requirements for the selection of process control, and requires the alloy grain structure to be uniform and fine. The current process is to directly extrude after the alloy ingot is homogenized. The grain structure of the profile is coarse, and it is difficult to achieve the requirements of high strength and high elongation after artificial aging treatment.

[0004] Research on the hot deformation behavior and heat treatment process of a new type of Al-Mg-Si-Cu alloy extrusion profile, Yuan Dong, Master's thesis of Central South University. It is stated in the first chapter that the current aluminum profiles use Al-Mg-Si series alloys, which are obtained by ingot homogenization annealing and extrusion heat treatment. The production process flow adopted is: melting and casting of the original ingot, homogenization treatment, cooling, extrusion preheating, extrusion, quenching, cold drawing, straightening, cutting the head and tail, and aging. The tensile strength of the T5 state extrusion profile produced industrially reaches 325 MPa, the yield strength reaches 275 MPa, the elongation is above 12%, and the hardness reaches above 120 HV. The material properties need to be further improved. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a preparation method of an aluminum alloy extrusion profile to improve the strength and elongation of the aluminum alloy extrusion profile.

[0006] An embodiment of the present invention provides a preparation method of an aluminum alloy extrusion profile. The raw material components of the aluminum alloy extrusion profile are melted and cast to obtain an ingot, and then homogenization treatment, three-way high-temperature upsetting and drawing, high-temperature annealing, cryogenic three-way compression, high-temperature extrusion, cooling, and aging treatment are carried out to obtain the aluminum alloy extrusion profile; The temperature of the three-way hot upsetting and drawing is 500-560°C, the temperature of the hot annealing is 540-580°C, the temperature of the cryogenic three-way compression is -180--150°C, and the temperature of the hot extrusion is 500-540°C.

[0007] Optionally, the aluminum alloy extruded profile comprises the following raw material components in parts by weight: Mg 0.6-1.4%, Si 0.8-1.2%, Cu 0.6-1.1%, Mn 0.06-0.2%, Cr 0.05-0.1%, Zn 0.04-0.1%, Ti 0.03-0.1%, Fe 0.1-0.5%, and the balance is A1.

[0008] Preferably, the aluminum alloy extruded profile comprises the following raw material components in parts by weight: Mg 0.8%, Si 0.9%, Cu 0.8%, Mn 0.1%, Cr 0.05%, Zn 0.06%, Ti 0.04%, Fe 0.15%, and the balance is A1.

[0009] Preferably, the heat preservation time of the cryogenic three-way compression is 20-400 min, and the compression deformation amount is 10-20%.

[0010] Preferably, the temperature of the homogenization treatment is 500-560°C, and the heat preservation time is 9-12 h.

[0011] Preferably, after the homogenization treatment, cooling is carried out. The cooling method is to cool in the furnace to 200°C, then carry out air cooling, and remove the surface defects after cooling to below 60°C.

[0012] Preferably, the deformation speed of the three-way hot upsetting and drawing is 10-30 mm / s, and the pass compression amount is 40-60%.

[0013] Preferably, the heat preservation time of the hot annealing is 2-5 h, and the quenching method is air cooling.

[0014] Preferably, the extrusion speed of the hot extrusion is 0.5-2.0 mm / s, and the cooling method after extrusion is online water mist cooling.

[0015] Preferably, the temperature of the aging treatment is 160-190°C, and the heat preservation is 15-20 h.

[0016] Preferably, the melting temperature is 710-750°C, then degassing and refining (time is 20-30 min) is carried out, slag is skimmed off, preferably standing for 20-40 min, and then the aluminum melt passes through online wire feeding, degassing, filtering and casting in sequence to obtain an ingot.

[0017] The beneficial effects of the present invention are as follows. Generally speaking, aluminum alloy extrusion profiles cannot be processed by cryogenic compression. The reasons are as follows: There are conflicts in the material processing temperature window because traditional aluminum alloy extrusion requires heating the billet to 400 - 500 °C (dynamic recrystallization temperature range). At this time, the plastic flow stress of the material is significantly reduced, and the extrusion energy consumption is controllable. Secondly, there is a risk of deterioration of the microstructure, resulting in the deterioration of microdefects and mechanical properties. Deep-temperature forging will hinder the thermally activated dislocation movement of aluminum alloy, inhibit the occurrence of dynamic recovery and recrystallization, lead to an exacerbation of the work-hardening effect, a sharp increase in dislocation density, and the ultra-high density dislocations caused by cryogenic forging are not eliminated by the dynamic recrystallization of high-temperature extrusion. As a result, the elongation of the final product decreases. Local shear bands or cracking are likely to occur during subsequent extrusion. The texture after cryogenic forging may deviate from the optimal extrusion orientation, reducing the extrusion formability of the material.

[0018] To avoid the adverse effects of cryogenic compression on aluminum alloy extrusion profiles, cryogenic compression is usually carried out after extrusion forming. The present invention discovers that before high-temperature extrusion forming, three-way high-temperature upsetting and drawing, high-temperature annealing, and cryogenic three-way compression are also carried out, and by controlling the temperature of the three-way high-temperature upsetting, the strength and elongation of the material can be significantly improved.

[0019] The present invention first uses the multi-directional upsetting and drawing process to forge and eliminate defects such as porosity and gas holes inside the alloy ingot, improve the density of the alloy, and at the same time refine the alloy grains during the multi-directional upsetting and drawing process, enhancing the forming ability, toughness, and reliability of subsequent processing. High-temperature annealing can effectively eliminate the internal residual stress of the alloy and improve the microstructure, making the physical and mechanical properties of the alloy tend to be consistent, providing the initial material property conditions for subsequent forming. Cryogenic three-way compression can effectively refine the coarse second-phase structure in the alloy, providing heterogeneous nucleation points during the subsequent hot extrusion process, thereby effectively refining the grain structure and improving the strength and plasticity of the alloy. Finally, high-temperature extrusion forming is carried out, which can significantly reduce the grains of the material and improve the strength and elongation of the material.

[0020] The alloy of the present invention has the characteristics of high mechanical properties and fine grain structure, and is suitable for preparing shell structural parts in the electronic 3C field, and is also suitable for preparing some profiles, pipes, and bars with certain strength requirements and high anodic oxidation effects. Specific embodiments

[0021] Example 1 A preparation method for an Al-Mg-Si-Cu alloy extrusion profile includes the following steps: Ingredient preparation: The weight percentages of the alloy components are as follows: Mg 0.8%, Si 0.9%, Cu 0.8%, Mn 0.1%, Cr 0.05%, Zn 0.06%, Ti 0.04%, Fe 0.15%, and the balance is A1 and unavoidable impurities.

[0022] Casting: Place the prepared alloy ingredients and high-purity aluminum ingots with a purity of 99.99% in a sealed melting furnace. Then, heat it up to 725°C for melting. Skim the slag, degas, and filter inside the furnace. Finally, it enters the mold to solidify into an ingot.

[0023] Homogenization treatment: Subject the ingot to homogenization heat treatment. The soaking furnace is a trolley-type soaking furnace. Argon is used for atmosphere protection inside the furnace. The heating rate is less than 20°C / h. Heat it up to 550 ± 3°C and hold for 12 hours. The cooling method is to cool it in the furnace until 200°C, then open the furnace door and move it out of the furnace chamber for air cooling. Subsequently, perform sawing and milling to remove the surface structure of the ingot.

[0024] Three-direction high-temperature upsetting and drawing: Heat the ingot with the skin removed, and perform three-direction upsetting and cogging treatment through a forging press. The initial forging temperature of the ingot is 500°C, the deformation speed is 20 mm / s, and the reduction per pass is 50%.

[0025] High-temperature annealing: Subject the billet after the above three-direction upsetting and drawing to high-temperature annealing treatment. The annealing temperature is 560°C, the holding time is 3 hours, and after the holding is completed, air cooling is carried out.

[0026] Deep cryogenic three-direction compression: Cool the solution-treated alloy billet by spraying liquid nitrogen. After cooling to -160°C and holding for 10 minutes, perform three-direction compression treatment. The strain is 2%, and liquid nitrogen spraying cooling is continuously maintained during the deformation process.

[0027] High-temperature extrusion forming: The extrusion forming temperature is 540°C, 2.0 mm / s, and online water mist cooling is carried out after extrusion.

[0028] Aging treatment: Subject the extruded bar to aging in an aging furnace. Heat it up to 170°C, hold for 15 hours, and then take it out of the furnace for air cooling.

[0029] Comparative Example 1

[0030] A preparation method of an Al-Mg-Si-Cu alloy extrusion profile, comprising the following steps: Ingredient preparation: The weight percentages of the alloy components are as follows: Mg 0.8%, Si 0.9%, Cu 0.8%, Mn 0.1%, Cr 0.05%, Zn 0.06%, Ti 0.04%, Fe 0.15%, and the balance is Al and unavoidable impurities.

[0031] Casting: Place the prepared alloy ingredients and high-purity aluminum ingots with a purity of 99.99% in a sealed melting furnace. Then, heat it up to 725°C for melting. Skim the slag, degas, and filter inside the furnace. Finally, it enters the mold to solidify into an ingot.

[0032] Homogenization treatment: The ingot is subjected to homogenization heat treatment. The soaking furnace is a trolley-type soaking furnace, and argon is used for atmosphere protection in the furnace. The heating rate is less than 20 °C / h. It is heated to 550 ± 3 °C, held for 12 h, and the cooling method is to cool with the furnace to 200 °C, then open the furnace door and move it out of the furnace chamber for air cooling. Subsequently, sawing and milling are carried out to remove the surface structure of the ingot.

[0033] Hot extrusion forming: The extrusion forming temperature is 540 °C, 2.0 mm / s, and it is cooled by on-line water mist after extrusion.

[0034] Aging treatment: The extruded bars are aged in an aging furnace, heated to 170 °C, held for 15 h, and then taken out of the furnace for air cooling.

[0035] Comparative example 2

[0036] A preparation method of an Al-Mg-Si-Cu alloy extruded profile, comprising the following steps: Batching: The weight percentages of alloy components are as follows: Mg 0.8%, Si 0.9%, Cu 0.8%, Mn 0.1%, Cr 0.05%, Zn 0.06%, Ti 0.04%, Fe 0.15%, and the balance is A1 and unavoidable impurities.

[0037] Melting and casting: The prepared alloy batch and high-purity aluminum ingots with a purity of 99.99% are placed in a sealed melting furnace, and then heated to 725 °C for melting. The slag is skimmed, degassed and filtered in the furnace, and finally solidified into an ingot in a mold.

[0038] Homogenization treatment: The ingot is subjected to homogenization heat treatment. The soaking furnace is a trolley-type soaking furnace, and argon is used for atmosphere protection in the furnace. The heating rate is less than 20 °C / h. It is heated to 550 ± 3 °C, held for 12 h, and the cooling method is to cool with the furnace to 200 °C, then open the furnace door and move it out of the furnace chamber for air cooling. Subsequently, sawing and milling are carried out to remove the surface structure of the ingot.

[0039] Three-way hot upsetting and drawing: The ingot is heated and subjected to three-way upsetting and drawing blanking treatment by a forging press. The initial forging temperature of the ingot is 500 °C, the deformation speed is 20 mm / s, and the pass deformation amount is 50%.

[0040] High-temperature annealing: The billet after the above three-way upsetting and drawing is subjected to high-temperature annealing treatment. The annealing temperature is 560 °C, the holding time is 3 h, and it is air-cooled after the holding is completed.

[0041] Hot extrusion forming: The extrusion forming temperature is 540 °C, 2.0 mm / s, and it is cooled by on-line water mist after extrusion.

[0042] Aging treatment: The extruded bars are aged in an aging furnace, heated to 170 °C, held for 15 h, and then taken out of the furnace for air cooling.

[0043] Comparative Example 3

[0044] A preparation method of an Al-Mg-Si-Cu alloy extrusion profile, comprising the following steps: Batching: The weight percentages of the alloy components are as follows: Mg 0.8%, Si 0.9%, Cu 0.8%, Mn 0.1%, Cr 0.05%, Zn 0.06%, Ti 0.04%, Fe 0.15%, and the balance is Al and inevitable impurities.

[0045] Melting and casting: Place the prepared alloy batch and high-purity aluminum ingots with a purity of 99.99% in a sealed melting furnace, then heat up to 725 °C for melting, skim the slag, degas and filter in the furnace, and finally enter the mold to solidify into ingots.

[0046] Homogenization treatment: Perform homogenization heat treatment on the ingots. The soaking furnace is a trolley-type soaking furnace, and argon is used for atmosphere protection in the furnace. The heating rate is less than 20 °C / h, heat up to 550 ± 3 °C, keep the temperature for 12 h, and the cooling method is to cool with the furnace to 200 °C, then open the furnace door and move out of the furnace chamber for air cooling. Subsequently, perform sawing and milling to remove the surface structure of the ingots.

[0047] Deep cryogenic triaxial compression: Cool the solution-treated alloy billet by means of liquid nitrogen spraying, cool to -160 °C, keep the temperature for 10 min, and then perform triaxial compression treatment. The strain is 2%, and liquid nitrogen spraying cooling is continuously maintained during the deformation process.

[0048] Hot extrusion forming: The extrusion forming temperature is 540 °C, 2.0 mm / s, and water mist cooling is performed online after extrusion.

[0049] Aging treatment: Age the extruded bars in an aging furnace, heat up to 170 °C, keep the temperature for 15 h, and then take them out of the furnace for air cooling.

[0050] Comparative Example 4

[0051] A preparation method of an Al-Mg-Si-Cu alloy extrusion profile, comprising the following steps: Batching: The weight percentages of the alloy components are as follows: Mg 0.8%, Si 0.9%, Cu 0.8%, Mn 0.1%, Cr 0.05%, Zn 0.06%, Ti 0.04%, Fe 0.15%, and the balance is Al and inevitable impurities.

[0052] Melting and casting: Place the prepared alloy batch and high-purity aluminum ingots with a purity of 99.99% in a sealed melting furnace, then heat up to 725 °C for melting, skim the slag, degas and filter in the furnace, and finally enter the mold to solidify into ingots.

[0053] Homogenization treatment: The ingot is subjected to homogenization heat treatment. The soaking furnace is a trolley-type soaking furnace, and argon is used for atmosphere protection in the furnace. The heating rate is less than 20 °C / h. It is heated to 550 ± 3 °C, held for 12 h, and the cooling method is to cool with the furnace to 200 °C, then open the furnace door and move it out of the furnace chamber for air cooling. Subsequently, sawing and milling are carried out to remove the surface structure of the ingot.

[0054] Three-way hot upsetting and drawing: The skinned ingot is heated and subjected to three-way upsetting and blanking treatment by a forging press. The initial forging temperature of the ingot is 400 °C, the deformation speed is 20 mm / s, and the reduction per pass is 50%.

[0055] High-temperature annealing: The billet after the above three-way upsetting and drawing is subjected to high-temperature annealing treatment. The annealing temperature is 560 °C, the holding time is 3 h, and after the holding is completed, it is air-cooled.

[0056] Deep cryogenic three-way compression: The solution-treated alloy billet is cooled by liquid nitrogen spraying. After cooling to -160 °C and holding for 10 min, three-way compression treatment is carried out, and the strain is 2%. During the deformation process, liquid nitrogen spraying cooling is continuously maintained.

[0057] Hot extrusion forming: The extrusion forming temperature is 540 °C, 2.0 mm / s, and it is cooled by on-line water mist after extrusion.

[0058] Aging treatment: The extruded bar is aged in an aging furnace. It is heated to 170 °C, held for 15 h, and then taken out of the furnace for air cooling.

[0059] Comparative example 5

[0060] A preparation method of an Al-Mg-Si-Cu alloy extrusion profile, comprising the following steps: Ingredient preparation: The weight percentages of the alloy components are as follows: Mg 0.8%, Si 0.9%, Cu 0.8%, Mn 0.1%, Cr 0.05%, Zn 0.06%, Ti 0.04%, Fe 0.15%, and the balance is A1 and unavoidable impurities.

[0061] Melting and casting: The prepared alloy ingredients and high-purity aluminum ingots with a purity of 99.99% are placed in a sealed melting furnace, and then heated to 725 °C for melting. The slag is skimmed, degassed and filtered in the furnace, and finally solidified into an ingot in a mold.

[0062] Homogenization treatment: The ingot is subjected to homogenization heat treatment. The soaking furnace is a trolley-type soaking furnace, and argon is used for atmosphere protection in the furnace. The heating rate is less than 20 °C / h. It is heated to 550 ± 3 °C, held for 12 h, and the cooling method is to cool with the furnace to 200 °C, then open the furnace door and move it out of the furnace chamber for air cooling. Subsequently, sawing and milling are carried out to remove the surface structure of the ingot.

[0063] Three-way hot upsetting and drawing: Heat the ingot of the car body, and perform three-way upsetting and drawing for blanking through a forging press. The initial forging temperature of the ingot is 500 °C, the deformation speed is 20 mm / s, and the deformation per pass is 50%.

[0064] Hot annealing: Perform hot annealing treatment on the blank after the above three-way upsetting and drawing. The annealing temperature is 560 °C, the holding time is 3 h, and after the holding is completed, air cooling is carried out.

[0065] Hot extrusion forming: The extrusion forming temperature is 540 °C, 2.0 mm / s, and online water mist cooling is carried out after extrusion.

[0066] Deep cryogenic three-way compression: Cool the solution-treated alloy blank by means of liquid nitrogen spraying. After cooling to -160 °C and holding for 10 min, perform three-way compression treatment. The strain is 2%, and liquid nitrogen spraying cooling is continuously maintained during the deformation process.

[0067] Aging treatment: Perform aging on the extruded bar in an aging furnace. Heat up to 170 °C, hold for 15 h, and then take it out of the furnace for air cooling.

[0068] Test the mechanical properties of the aluminum alloy extruded profiles of Example 1 and Comparative Examples 1-5, and obtain the mechanical property table of the aluminum alloy extruded profiles as shown in Table 1.

[0069] Table 1 Mechanical property table of aluminum alloy extruded profiles

[0070] As can be seen from Table 1, after homogenizing the Al-Mg-Si-Cu alloy ingot, successively performing hot upsetting and drawing, annealing, and deep cryogenic compression, and then performing hot extrusion forming, the grains of the material can be significantly reduced, and the strength and elongation of the material can be improved.

[0071] Those of ordinary skill in the art should understand that: The discussion of any above embodiment is only exemplary, and is not intended to imply that the protection scope of this application is limited to these examples; under the idea of this application, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations in different aspects of one or more embodiments in this application as described above, and they are not provided in detail for the sake of brevity.

[0072] One or more embodiments of this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of this application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of one or more embodiments of this application shall be included in the protection scope of this application.

Claims

1. A preparation method of an aluminum alloy extrusion profile, characterized in that, The raw material components of the aluminum alloy extrusion profile are melted and cast to obtain an ingot, which is then subjected to homogenization treatment, three-directional hot upsetting and drawing, hot annealing, cryogenic three-directional compression, hot extrusion, cooling, and aging treatment to obtain the aluminum alloy extrusion profile; The temperature of the three-directional hot upsetting and drawing is 500 - 560 °C, the temperature of the hot annealing is 540 - 580 °C, the temperature of the cryogenic three-directional compression is -180 - -150 °C, and the temperature of the hot extrusion is 500 - 540 °C.

2. The preparation method according to claim 1, characterized in that, The aluminum alloy extrusion profile comprises the following raw material components in parts by weight: 0.6 - 1.4% of Mg, 0.8 - 1.2% of Si, 0.6 - 1.1% of Cu, 0.06 - 0.2% of Mn, 0.05 - 0.1% of Cr, 0.04 - 0.1% of Zn, 0.03 - 0.1% of Ti, 0.1 - 0.5% of Fe, and the balance is Al.

3. The preparation method according to claim 2, characterized in that, The aluminum alloy extrusion profile comprises the following raw material components in parts by weight: 0.8% of Mg, 0.9% of Si, 0.8% of Cu, 0.1% of Mn, 0.05% of Cr, 0.06% of Zn, 0.04% of Ti, 0.15% of Fe, and the balance is Al.

4. The preparation method according to any one of claims 1 to 3, characterized in that, The heat preservation time of the cryogenic three-directional compression is 20 - 400 min, and the compression deformation amount is 10 - 20%.

5. The preparation method according to any one of claims 1-3, characterized in that, The temperature of the homogenization treatment is 500 - 560 °C, and the heat preservation time is 9 - 12 h.

6. The preparation method according to any one of claims 1 to 3, characterized in that, After the homogenization treatment, cooling is carried out. The cooling method is to cool in the furnace to 200 °C, then carry out air cooling, and remove the surface defects after cooling to below 60 °C.

7. The preparation method according to any one of claims 1 to 3, characterized in that, The deformation speed of the three-directional hot upsetting and drawing is 10 - 30 mm / s, and the pass compression amount is 40 - 60%.

8. The preparation method according to any one of claims 1-3, characterized in that, The heat preservation time of the hot annealing is 2 - 5 h, and the quenching method is air cooling.

9. The preparation method according to any one of claims 1 to 3, characterized in that, The extrusion speed of the hot extrusion is 0.5 - 2.0 mm / s, and the cooling method after extrusion is on-line water mist cooling.

10. The preparation method according to any one of claims 1 to 3, characterized in that, The temperature of the aging treatment is 160 - 190 °C, and the heat preservation is 15 - 20 h.

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