High-strength and high-toughness aluminum alloy profile, preparation method and application thereof

Abstract

This invention belongs to the field of metal material processing technology, specifically relating to a high-strength, high-toughness aluminum alloy profile, its preparation method, and its application. The preparation method of this invention includes the following steps: preparing raw materials according to the aluminum alloy formula and casting them into a cast ingot; homogenizing the resulting cast ingot and water-cooling it to room temperature after removal from the furnace; heating the homogenized cast ingot to 520±10℃, with a temperature gradient of 8-12℃ between the head and tail of the cast ingot; heating the extrusion die to 480±5℃; heating the die cylinder to 435±5℃; extruding the preheated cast ingot using an extruder within the extrusion die; and subjecting the resulting product to online solution treatment, straightening treatment, and artificial aging treatment. The aluminum alloy extruded profile of this invention has a tensile strength ≥260MPa, a yield strength of 240-280MPa, an elongation ≥10%, and a bending angle ≥100°, and can be used to prepare automotive side sill reinforcement beams.

Description

Technical Field

[0001] This invention belongs to the field of metal material processing technology, specifically relating to a high-strength and high-toughness aluminum alloy profile, its preparation method, and its application. Background Technology

[0002] With increasing demands for energy conservation, environmental protection, lightweighting, and high mobility in automobiles, automotive lightweighting is developing rapidly. Aluminum alloys, with their moderate strength, light weight, and ease of forming, are suitable for automotive lightweight design. For vehicle safety considerations, the side sill reinforcement beam is a key component of the vehicle body structure. Located in the cavity between the inner side panel and the inner sill panel, it extends laterally along the vehicle and primarily serves multiple functions including support, collision protection, and weight reduction. Therefore, it is desirable for the raw material to possess both high strength and good toughness. Currently, the customer's performance requirements for this profile are: tensile strength ≥260MPa, yield strength 240-280MPa, elongation ≥10%, and bending angle ≥100°. Existing aluminum alloy profiles cannot meet these performance requirements. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a high-strength, high-toughness aluminum alloy profile, its preparation method, and its application. The aluminum alloy profile obtained by this invention has a tensile strength ≥260MPa, a yield strength of 240-280MPa, an elongation ≥10%, and a bending angle ≥100°. It possesses high strength and high toughness, and can meet the performance requirements of automotive side sill reinforcement beams.

[0004] To achieve the above technical objectives, the technical solution adopted in the embodiments of the present invention is as follows: In a first aspect, embodiments of the present invention provide a method for preparing a high-strength, high-toughness aluminum alloy profile, comprising the following steps: Step S1, Aluminum rod casting: Prepare raw materials according to the aluminum alloy formula and cast them into rods; Step S2, Homogenization treatment: The cast rod obtained in step S1 is kept at 565±10℃ for 8 hours for homogenization treatment, and then removed from the furnace and cooled to room temperature by water. Step S3, Preheating: Heat the homogenized casting rod obtained in step S2 to 520±10℃, with a temperature gradient of 10℃ between the head and tail of the casting rod; heat the extrusion die to 480±5℃; heat the die cylinder to 435±5℃. Step S4, Extrusion: The preheated casting rod from step S3 is extruded in the extrusion die using an extrusion press at a speed of 3-4 m / min, ensuring an outlet temperature > 530℃; Step S5, Solution treatment: The product obtained in step S4 is subjected to online solution treatment, which is carried out by online water cooling. Step S6, Straightening: Straighten the product obtained in step S5; Step S7, Artificial aging treatment: The forgings obtained in step S6 are subjected to artificial aging treatment: aging temperature 175±5℃, holding time 6-6.5h.

[0005] Furthermore, the extrusion die includes a punch and a die, and the die includes a first circular die base body, a main forming cavity, a first working zone and a first diversion hole; The first circular mold base body is provided with a positioning boss; The main forming cavity is a centrally symmetrical double rectangular cavity structure, located in the central area of ​​the first circular mold base body, with a connecting bridge structure in the middle for forming the main cross section of the workpiece. The first working zone is distributed on the upper and lower sides of the main molding cavity. The first working zone is a closed cavity arranged symmetrically on the upper and lower sides and is connected to the main molding cavity. The first diversion hole is an elliptical guide groove symmetrically distributed on the left and right sides of the main forming cavity, which is connected to the main forming cavity and the first working zone, and is used to guide the flow of metal material.

[0006] Furthermore, the punch includes a second circular die base body, which is an upper and lower mating structure with the first circular die base body. The punch and die are positioned circumferentially and radially by mounting holes and bolts.

[0007] Furthermore, a bridge structure is provided at the entrance of the first working zone. The cross-sectional width of the bridge is smaller than the cross-sectional width of the first working zone, which is used to form a material flow resistance and force the metal to fill the main forming cavity.

[0008] Furthermore, the first diversion hole smoothly transitions to the main forming cavity, and the cross-sectional dimensions of the first diversion hole gradually narrow from the outside towards the main forming cavity, in order to evenly distribute the flow of metal material and avoid uneven loading during forming.

[0009] Furthermore, the second circular mold base body has a raised cylindrical core at its center, which is correspondingly provided with the main molding cavity and can be adapted to the main molding cavity.

[0010] Furthermore, the main forming cavity, the first working zone, and the first diversion hole are integrally formed and are distributed in an axisymmetric manner.

[0011] Secondly, embodiments of the present invention provide a high-strength, high-toughness aluminum alloy profile, prepared using the method described in the first aspect. The alloy element composition, by mass percentage, includes: Si 0.6%-0.8%, Fe 0.3%-0.45%, Cu 0.25%-0.4%, Mn 0.1%-0.14%, Mg 0.8%-1.0%, Cr 0.2%-0.3%, Zn≤0.15%, Ti≤0.15%, other individual elements≤0.05%, other impurity elements total≤0.15%, and the balance being Al.

[0012] Furthermore, the aluminum alloy extruded profile has a tensile strength ≥260MPa, a yield strength of 240-280MPa, an elongation ≥10%, and a bending angle ≥100°.

[0013] Thirdly, embodiments of the present invention provide an application of a high-strength, high-toughness aluminum alloy profile, wherein the aluminum alloy extruded profile is used to manufacture a reinforcing beam for the side sill of an automobile.

[0014] The beneficial effects of the technical solution provided by the embodiments of the present invention are as follows: The aluminum alloy profile obtained by this invention has a tensile strength ≥260MPa, a yield strength of 240-280MPa, an elongation ≥10%, and a bending angle ≥100°. It has high strength and high toughness and can meet the performance requirements of automotive side door sill reinforcement beams. Attached Figure Description

[0015] Figure 1 This is a side view of the extrusion die used in an embodiment of the present invention.

[0016] Figure 2 yes Figure 1 A top view of the die cavity in an extrusion die.

[0017] Figure 3 This is a top view of the die cavity in the extrusion die used in the comparative example of this invention.

[0018] Figure 4 This is a cross-sectional view of the die cavity in the extrusion die used in the comparative example of this invention.

[0019] Explanation of reference numerals in the attached drawings: A-Punch; B-Die; 1-First circular mold base body; 3-Main forming cavity; 4-First working zone; 5-First diversion hole; 6-Positioning boss; 1'-Second circular mold base body; 3'-Cylindrical core; 7-Circular mold base body; 8-Positioning boss; 9-Mounting hole; 10-Second diversion hole; 11-Diversion bridge; 12-Welding chamber; 13-Second working zone. Detailed Implementation

[0020] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "inner" and "outer", "upper" and "lower", "left" and "right" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention.

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0022] Example 1 A method for manufacturing 6082 aluminum alloy profiles includes the following steps: Step S1, Aluminum Rod Melting and Casting: Prepare raw materials according to the alloy element composition of 6082 aluminum alloy and melt and cast them into rods. By mass percentage, the alloy element composition includes: Si: 0.7%, Fe: 0.37%, Cu: 0.27%, Mn: 0.12%, Mg: 0.9%, Cr: 0.25%, Zn: 0.05%, Ti: 0.05%, other individual elements ≤0.05%, other impurity elements total ≤0.15%, and the balance is Al.

[0023] Step S2, Homogenization treatment: The cast rod obtained in step S1 is kept at 575℃ for 8 hours for homogenization treatment, and then taken out of the furnace and water-cooled to room temperature. Step S3, Preheating: Heat the homogenized casting rod obtained in step S2 to 510°C, with a temperature gradient of 10°C between the head and tail of the casting rod; heat the extrusion die to 480°C; heat the die cylinder to 435°C. Step S4, Extrusion: The preheated casting rod from step S3 is extruded using an extrusion press at a speed of 3 m / min. Step S5, Solution treatment: The product obtained in step S4 is subjected to online solution treatment, which is carried out by online water cooling. Step S6, Straightening: Straighten the product obtained in step S5; Step S7, Artificial aging treatment: The forgings obtained in step S6 are subjected to artificial aging treatment: aging temperature 175℃, holding time 6h; The extrusion die structure used in this embodiment is shown in the figure. Figure 1 As shown, the extrusion die includes a punch A and a die B.

[0024] like Figure 2As shown, the cavity B includes a first circular mold base body 1, a main forming cavity 3, a first working zone 4, and a first diversion hole 5; The first circular mold base body 1 is provided with a positioning boss 6; The main forming cavity 3 is a centrally symmetrical double rectangular cavity structure, located in the central area of ​​the first circular mold base body 1, with a connecting bridge structure in the middle for forming the main cross section of the workpiece; The upper and lower sides of the main molding cavity 3 are provided with first working zones 4. The first working zones 4 are closed cavities arranged symmetrically in the upper and lower parts and are connected to the main molding cavity 3. The first diversion hole 5 is an elliptical guide groove symmetrically distributed on the left and right sides of the main forming cavity 3, which is connected to the main forming cavity 3 and the first working zone 4, and is used to guide the flow of metal material.

[0025] The punch A includes a second circular die base body 1', which is an upper and lower mating structure with the first circular die base body 1. The punch A and the die B are positioned circumferentially and radially by the positioning guide component 2.

[0026] The entrance of the first working zone 4 is provided with a bridge structure. The cross-sectional width of the bridge is smaller than the cross-sectional width of the compartment of the first working zone 4. This structure is used to create resistance to material flow and force the metal to fill the main forming cavity 3.

[0027] The first diversion hole 5 smoothly transitions with the main forming cavity 3. The cross-sectional dimensions of the first diversion hole 5 gradually narrow from the outside towards the main forming cavity 3, which is used to evenly distribute the flow of metal material and avoid uneven loading during forming.

[0028] The second circular mold base body 1' has a raised cylindrical core 3' at its center, which is correspondingly set to the main molding cavity 3 and can be adapted to the main molding cavity 3.

[0029] The main forming cavity 3, the first working zone 4 and the first diversion hole 5 are integrally formed and are distributed axially symmetrically.

[0030] The first working zone 4 has drainage holes inside, and the entire extrusion die has no secondary welding, which makes the metal flow stable, the grains fine and uniform, reduces structural defects, and thus improves the mechanical properties of the material.

[0031] Example 2 This embodiment provides a method for preparing 6082 aluminum alloy profiles. The processing technology is basically the same as the processing technology in Embodiment 1 in terms of steps and parameters. The difference is that in this embodiment, the casting rod is heated to 520°C in step S3 and the extrusion speed is 4m / min in step S4.

[0032] Comparative Example 1 This embodiment provides a method for manufacturing aluminum alloy profiles. The processing technology is the same as that in Embodiment 1 in terms of steps and parameters, except that the extrusion die structure used in this embodiment is as follows: Figure 3 and Figure 4 It includes a punch and a die, wherein the die includes a circular die base body 7, the circular die base body 7 is provided with a positioning boss 8 and mounting holes 9, the mounting holes 9 are four bolt holes evenly arranged on the circular die base body 7, used to fix the die on the extrusion equipment to prevent displacement or rotation during operation, the positioning boss 8 is used to cooperate with the punch or equipment to achieve axial coaxial positioning of the die; The circular mold base body 7 is also provided with a flow-dividing welding system, including a second flow-dividing hole 10, a flow-dividing bridge 11 and a welding chamber 12. The second flow-dividing hole 10 consists of four symmetrical cavities distributed around the center of the circular mold base body 7, which are used to divide the metal billet entering the mold into multiple strands to reduce flow resistance. A flow divider bridge 11 is provided between adjacent second flow divider holes 10. The flow divider bridge 11 is used to support the mold and prevent deformation. The welding chamber 12 is formed in the transition area behind the second diversion hole 10. Multiple metal streams entering from the second diversion hole 10 converge and re-weld here, eliminating the diversion gap and forming a continuous and uniform metal flow. The circular mold base body 7 is also provided with a second working belt 13, which is used to correct the flow rate and direction of the metal flow and finally shape it into the required cross-sectional shape.

[0033] Figure 2 The mold structure shown has a two-stage welding process. There will be weld seams in the thick-walled areas (formed by the convergence and welding of two metal streams under the bridge). The metal flow is unstable, the grains are coarse and uneven, which increases the structural defects and thus reduces the mechanical properties of the material.

[0034] Comparative Example 2 A method for preparing aluminum alloy profiles, the processing technology of which is basically the same as the processing technology in Example 2 in terms of steps and parameters, the difference being that the extrusion die structure used is the same as that in Comparative Example 1.

[0035] Comparative Example 3 A method for preparing aluminum alloy profiles, the processing technology of which is basically the same as the processing technology in Example 2 in terms of steps and parameters, the difference being that the extrusion speed in step S4 is 2m / min.

[0036] Comparative Example 4 A method for preparing aluminum alloy profiles, the processing technology of which is basically the same as the processing technology in Example 2 in terms of steps and parameters, the difference being that the casting rod is heated to 490°C in step S3.

[0037] The tensile and bending properties of Examples 1, 2 and Comparative Examples 1-4 were tested, and the test results are shown in the table below.

[0038] Table 1 Performance test data for different solutions

[0039] Test results show that the aluminum alloy side sill reinforcement beam extruded profiles produced by this manufacturing method meet the following requirements after artificial aging: tensile strength ≥260MPa, yield strength 240-280MPa, elongation ≥10%, and bending angle ≥100°.

[0040] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing a high-strength, high-toughness aluminum alloy profile, characterized in that, Includes the following steps: Step S1, Aluminum rod casting: Prepare raw materials according to the aluminum alloy formula and cast them into rods; Step S2, Homogenization treatment: The cast rod obtained in step S1 is kept at 565±10℃ for 8 hours for homogenization treatment, and then removed from the furnace and cooled to room temperature by water. Step S3, Preheating: Heat the homogenized casting rod obtained in step S2 to 520±10℃, with a temperature gradient of 8-12℃ between the head and tail of the casting rod; heat the extrusion die to 480±5℃; heat the die cylinder to 435±5℃. Step S4, Extrusion: The preheated casting rod from step S3 is extruded in the extrusion die using an extrusion press at a speed of 3-4 m / min, ensuring an outlet temperature > 530℃; Step S5, Solution treatment: The product obtained in step S4 is subjected to online solution treatment, which is carried out by online water cooling. Step S6, Straightening: Straighten the product obtained in step S5; Step S7, Artificial aging treatment: The forgings obtained in step S6 are subjected to artificial aging treatment: aging temperature 175±5℃, holding time 6-6.5h.

2. The method for preparing high-strength and high-toughness aluminum alloy profiles according to claim 1, characterized in that, The extrusion die includes a punch (A) and a die (B). The die (B) includes a first circular die base body (1), a main forming cavity (3), a first working zone (4), and a first diversion hole (5). The first circular mold base body (1) is provided with a positioning boss (6); The main forming cavity (3) is a centrally symmetrical double rectangular cavity structure, located in the central area of ​​the first circular mold base body (1), with a connecting bridge structure in the middle for forming the main cross section of the workpiece; The first working zone (4) is distributed on the upper and lower sides of the main molding cavity (3). The first working zone (4) is a closed cavity arranged symmetrically on the upper and lower sides and is connected to the main molding cavity (3). The first diversion hole (5) is an elliptical guide groove symmetrically distributed on the left and right sides of the main forming cavity (3), which is connected to the main forming cavity (3) and the first working zone (4) and is used to guide the flow of metal material.

3. The method for preparing high-strength and high-toughness aluminum alloy profiles according to claim 2, characterized in that, The punch (A) includes a second circular mold base body (1'), which is an upper and lower mating structure with the first circular mold base body (1). The punch (A) and the die (B) are positioned circumferentially and radially by mounting holes (2) and bolts.

4. The method for preparing high-strength and high-toughness aluminum alloy profiles according to claim 2, characterized in that, The first working zone (4) has a bridge structure at its entrance. The cross-sectional width of the bridge is smaller than the cross-sectional width of the first working zone (4) to form a material flow resistance and force the metal to fill the main forming cavity (3).

5. The method for preparing high-strength and high-toughness aluminum alloy profiles according to claim 2, characterized in that, The first diversion hole (5) smoothly transitions with the main forming cavity (3). The cross-sectional size of the first diversion hole (5) gradually narrows from the outside towards the main forming cavity (3) to uniformly distribute the flow of metal material and avoid uneven loading during forming.

6. The method for preparing high-strength and high-toughness aluminum alloy profiles according to claim 3, characterized in that, The second circular mold base body (1') has a raised cylindrical core (3') at its center, which is corresponding to the main molding cavity (3) and can be adapted to the main molding cavity (3).

7. The method for preparing the high-strength, high-toughness aluminum alloy profile according to any one of claims 2-6, characterized in that, The main forming cavity (3), the first working zone (4) and the first diversion hole (5) are integrally formed and are distributed in an axisymmetric manner.

8. A high-strength, high-toughness aluminum alloy profile, characterized in that, Prepared by the preparation method according to any one of claims 1-7, the alloying element composition by mass percentage includes: Si 0.6%-0.8%, Fe 0.3%-0.45%, Cu 0.25%-0.4%, Mn 0.1%-0.14%, Mg 0.8%-1.0%, Cr 0.2%-0.3%, Zn≤0.15%, Ti≤0.15%, other individual elements≤0.05%, other impurity elements total≤0.15%, and the balance being Al.

9. The high-strength, high-toughness aluminum alloy profile according to claim 8, characterized in that, The aluminum alloy extruded profile has a tensile strength ≥260MPa, a yield strength of 240-280MPa, an elongation ≥10%, and a bending angle ≥100°.

10. An application of a high-strength, high-toughness aluminum alloy profile, characterized in that, The aluminum alloy extruded profile is used to manufacture the side sill reinforcement beam of automobiles.

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