Aluminum alloy component, processing method therefor, and vehicle comprising same

Abstract

A processing method for an aluminum alloy component, comprising: preparing an aluminum alloy raw material into an aluminum alloy coil by means of a cast-rolling step, and forming the aluminum alloy coil into an aluminum alloy component by means of a hot stamping step. The processing method for an aluminum alloy component can improve production efficiency and production costs, and the resulting aluminum alloy component has good mechanical properties. Also provided are an aluminum alloy component and a vehicle.

Description

Aluminum alloy parts, their processing methods, and automobiles including them Technical Field

[0001] This invention belongs to the field of metal product processing. Specifically, this invention relates to an aluminum alloy part, its processing method, and an automobile including the same. Background Technology

[0002] Aluminum alloys are widely used due to their high performance-to-weight ratio, favorable corrosion resistance, and other factors.

[0003] For example, in order to improve the driving range and safety performance of electric vehicles, major automakers are increasingly using aluminum alloys.

[0004] The aluminum alloys used in the automotive industry mainly include the 2xxx (Al-Cu-Mg), 5xxx (Al-Mg), 6xxx (Al-Mg-Si), and 7xxx (Al-Zn-Mg-Cu) series. Among them, the 5xxx series aluminum alloys have excellent formability, the heat-treatable 2xxx series aluminum alloys have high strength and good weldability and forging properties, the 6xxx series aluminum alloys have both good formability in the T4 / T4P state and high paint-baking aging hardening response (the increase in yield strength of the alloy before and after painting), and the 7xxx series aluminum alloys have good strength and toughness.

[0005] High-strength aluminum alloys are widely used in aerospace, automobile manufacturing and other fields due to their excellent mechanical properties and corrosion resistance.

[0006] In the existing high-strength aluminum alloy product processing, the manufacturing cost of aluminum alloy sheets is high, and the hot stamping process requires solution treatment, which results in a slow production pace and high overall cost.

[0007] In response to this situation, some manufacturers use a long-process continuous hot rolling method to produce aluminum alloy sheets, while simultaneously performing a solution treatment on the sheets before hot stamping. However, this processing method is energy-intensive and cannot effectively solve the problems of slow production pace and high costs.

[0008] Therefore, there remains a demand in this field for rapid and cost-effective methods for processing aluminum alloy products. Summary of the Invention

[0009] The purpose of this invention is to provide a fast and cost-effective method for processing aluminum alloy products.

[0010] According to a first aspect of the present invention, a method for processing aluminum alloy parts is provided, characterized in that it includes:

[0011] Aluminum alloy raw materials are prepared into aluminum alloy coils through a casting and rolling process; and

[0012] Aluminum alloy coils are formed into aluminum alloy parts through a hot stamping process.

[0013] The casting and rolling process includes the following steps performed in sequence: smelting, electromagnetic stirring, slag removal, refining, furnace turning, settling, venting, online crystal refinement, degassing, filtration and slag removal, and casting and rolling.

[0014] The online crystal refinement is achieved by adding a grain refiner. The amount of grain refiner added, relative to the total weight of the aluminum alloy, results in a titanium content of 0.02 wt.% - 0.1 wt.%.

[0015] The nozzle opening for casting and rolling is 12-18mm, and the length of the casting and rolling zone reaches 70-90mm.

[0016] The aluminum alloy raw material is selected from the 2xxx, 6xxx and 7xxx series aluminum alloy materials.

[0017] According to a second aspect of the present invention, an aluminum alloy component is provided, which is prepared by the above-described processing method.

[0018] According to a third aspect of the present invention, an automobile is provided, which includes the aforementioned aluminum alloy parts.

[0019] The processing method for aluminum alloy parts of this invention can improve production efficiency and reduce production costs. The resulting aluminum alloy parts have good mechanical properties, such as tensile strength of at least 270 MPa, yield strength of at least 215 MPa, and elongation of at least 13%. Attached Figure Description

[0020] The present invention will be described in conjunction with the accompanying drawings to enable those skilled in the art to better understand the features and advantages of the invention, wherein:

[0021] Figure 1 shows a schematic diagram of the temperature-time curve in the hot stamping step of the aluminum alloy parts processing method of the present invention.

[0022] Figure 2 shows the state and appearance of the final cast-rolled plate obtained in Example 1.

[0023] Figure 3 shows the metallographic structure of the cast-rolled strip after the casting and rolling process in Example 1.

[0024] Figure 4 shows the metallographic structure of the components in Example 1 after aging baking.

[0025] Figures 5 and 6 show the morphology and appearance of the sheet material obtained in Comparative Example 2. Detailed Implementation

[0026] The technical solution of the present invention will be described in detail below.

[0027] According to a first aspect of the present invention, a method for processing aluminum alloy parts is provided, characterized in that it includes:

[0028] Aluminum alloy raw materials are prepared into aluminum alloy coils through a casting and rolling process; and

[0029] Aluminum alloy coils are formed into aluminum alloy parts through a hot stamping process.

[0030] The casting and rolling process includes the following steps performed in sequence: smelting, electromagnetic stirring, slag removal, refining, furnace turning, settling, venting, online crystal refinement, degassing, filtration and slag removal, and casting and rolling.

[0031] The online crystal refinement is achieved by adding a grain refiner. The amount of grain refiner added, relative to the total weight of the aluminum alloy, results in a titanium content of 0.02 wt.% - 0.1 wt.%.

[0032] The nozzle opening for casting and rolling is 12-18mm, and the length of the casting and rolling zone reaches 70-90mm.

[0033] The aluminum alloy raw material is selected from the 2xxx, 6xxx and 7xxx series aluminum alloy materials.

[0034] Preferably, the hot stamping step includes the following processes performed in sequence: cutting, heating, hot stamping, and artificial aging.

[0035] Preferably, the aluminum alloy raw material is a 6xxx series aluminum alloy material, such as 6016.

[0036] The aluminum alloy coil can have a suitable thickness, for example, 0.5-5mm.

[0037] Specifically, smelting involves melting the raw materials, sampling and testing the alloy composition, and adding different components as needed according to the alloy composition table.

[0038] Melting can be carried out in a melting furnace at a temperature, for example, in the range of 720-760°C, preferably 740-750°C.

[0039] The slag remover used in the slag removal process is a commonly used slag remover in this field.

[0040] Refining can be carried out at temperatures, for example, in the range of 730-770°C, preferably 740-745°C.

[0041] Preferably, the grain refiner is an aluminum-titanium-boron alloy and / or an aluminum-titanium master alloy.

[0042] By adding grain refiners, preferably aluminum-titanium-boron alloys and aluminum-titanium master alloys, the grains can be refined and the macrosegregation of the billet can be reduced, while avoiding increased costs and the introduction of new segregation.

[0043] Preferably, the degassing is carried out at 730-740°C.

[0044] Preferably, the degassing medium is argon.

[0045] The casting rolls used in casting and rolling can be lubricated with graphite emulsion.

[0046] Preferably, the diameter of the casting rolls used for casting and rolling is not less than 900 mm, for example, in the range of 900-1500 mm, and the rolling force is not less than 20000 KN, for example, in the range of 20000-40000 KN.

[0047] Preferably, the nozzle opening for casting and rolling is 12-15 mm.

[0048] The inventors discovered that by increasing the nozzle opening and the length of the casting zone, the residence time of the molten metal in the casting zone can be increased, thereby improving the solidification rate of the molten metal and thus improving the quality of the billet, especially reducing segregation.

[0049] Preferably, the casting and rolling speed is in the range of 300-1100 mm / min, and more preferably in the range of 400-700 mm / min.

[0050] The inventors discovered that reducing the casting and rolling speed reduced the formation of cracks.

[0051] Preferably, the cast-rolled coil is rapidly cooled after casting to achieve a supersaturated solution effect, which facilitates subsequent forming processes.

[0052] Preferably, the cooling rate is in the range of 100-300℃ / s.

[0053] The inventors discovered that by increasing the cooling intensity and reducing segregation, the quality of the cast billet was further improved.

[0054] In the hot stamping step, the roll material is first cut into a specified shape, such as a two-dimensional (2D) irregular plate.

[0055] Figure 1 shows a schematic diagram of the temperature-time curve in the hot stamping step of the aluminum alloy parts processing method of the present invention.

[0056] Referring to Figure 1, the cut sheet metal is placed in a heating furnace and heated from room temperature to the formed part T1 (0-a in Figure 1), and held at that temperature for a short time (ab in Figure 1). Then, the sheet metal is removed from the heating furnace and transferred to the mold (bc in Figure 1). At this time, the temperature of the sheet metal is T2. The press is closed to press the sheet metal into shape in the mold cavity and hold it under pressure for a certain time (cd in Figure 1). The resulting drawn part is removed from the mold cavity and then artificially aged. The mechanical properties of the product are improved by controlling the heating temperature and heating time.

[0057] In the processing method of the present invention, no solution treatment is performed before or during the hot stamping step.

[0058] Preferably, the heating temperature T1 of the sheet metal in the hot stamping step is in the range of 200 to 500°C.

[0059] Preferably, the heating time 'a' for heating the cut sheet material from room temperature to heating temperature T1 is in the range of 0.5-15 minutes.

[0060] Preferably, the sheet metal is transferred from the heating furnace to the mold within 15 seconds.

[0061] The mold may be equipped with a cooling system to cool the mold after the sheet metal is formed.

[0062] Preferably, the temperature at which the drawn part (i.e., the formed component) exits the mold is not higher than 100°C.

[0063] As described in this application, artificial aging refers to heating the formed parts to an artificial hardening temperature and maintaining that temperature until precipitation hardening is allowed to occur.

[0064] Preferably, the temperature for artificial aging during the hot stamping step is in the range of 100-200°C.

[0065] Those skilled in the art can select the required time for artificial aging based on the aluminum alloy raw material.

[0066] The processing method for aluminum alloy parts of the present invention can achieve fast and cost-effective processing of aluminum alloy products.

[0067] The inventors discovered that by combining measures such as adjusting the amount of fine refining agent added, increasing the nozzle opening, and increasing the length of the casting zone, the aluminum alloy parts obtained by the method of the present invention have good mechanical properties, such as tensile strength up to at least 270 MPa, yield strength up to 215 MPa, and elongation up to at least 13%.

[0068] According to a second aspect of the present invention, an aluminum alloy component is provided, which is prepared by the above-described processing method.

[0069] According to a third aspect of the present invention, an automobile is provided, which includes the aforementioned aluminum alloy parts.

[0070] The components may be structural parts such as B-pillar inner panel, B-pillar inner panel reinforcement, A-pillar inner panel, hinge reinforcement plate, floor beam, door inner panel, front and rear cover inner panels, floor skin, battery box cover and bottom guard plate, etc.

[0071] In this application specification and claims, the naming of aluminum alloys conforms to the latest regulations known in the art by the Aluminum Association. Each alloy within each series is registered with the Aluminum Association this year. For example, aluminum alloys in the 2xxx series are referred to as high-strength alloys and typically contain magnesium and copper as the main alloying element. Alloys in the 6xxx and 7xxx series are also referred to as high-strength alloys and are typically strengthened by heat treatment through the precipitation of their main alloying elements, which are silicon and magnesium for the 6xxx series and copper, zinc, and magnesium for the 7xxx series.

[0072] The terms "comprising" and "including" as used in this application cover situations where other elements not explicitly mentioned are also included, as well as situations where the elements mentioned are constituted.

[0073] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In the event of any discrepancy between the definitions of terms in this specification and their commonly understood meaning by one of ordinary skill in the art to which this invention pertains, the definitions set forth herein shall prevail.

[0074] Unless otherwise stated, all numerical values ​​for the amount of an ingredient, temperature, etc., used in the specification and claims are to be understood as being modified by the term "about". Therefore, unless otherwise indicated, the numerical parameters set forth herein are approximate values ​​that can be varied to obtain the desired performance.

[0075] Example

[0076] The following will further illustrate the concept, specific structure, and technical effects of the present invention with reference to embodiments, so that those skilled in the art can fully understand the purpose, features, and effects of the present invention. It will be readily understood by those skilled in the art that the embodiments described herein are merely illustrative, and the scope of the present invention is not limited thereto. Unless otherwise specified, the raw materials used in the embodiments are those commonly used in the art.

[0077] Example 1

[0078] In this embodiment, aluminum alloy 6016 with the composition shown in Table 1 is used as the aluminum alloy raw material:

[0079] Table 1

[0080] Follow these steps to process the parts:

[0081] Melting and electromagnetic stirring: According to the proportions shown in Table 1, add pure aluminum ingots and intermediate aluminum alloys to the melting furnace, heat and melt them into a melt. During the melting process, use electromagnetic stirring 2-3 times, each time for 5-10 minutes. When the temperature reaches 740-750℃, add slag remover, stir evenly and let stand for 5-10 minutes, and then remove the slag.

[0082] Composition adjustment: Take a sample from the melt to quickly test the chemical composition, then add material to adjust the alloy composition to meet the composition table 1.

[0083] Refining, furnace turning, and settling: After the sampling and testing are qualified, refine twice, each time for 20-30 minutes. After refining, let it stand for 5-10 minutes to remove slag and ensure that there is no residue on the surface. Turn the furnace at a melt temperature of 740-745℃ and let it stand in a holding furnace at 730-735℃.

[0084] Vertical plate discharge, online addition of Al-5Ti-1B wire, degassing, filtration, casting and rolling:

[0085] Slag removal speed of vertical plate: 1300~1500mm / min, slag removal time: 5min, nozzle opening: 13mm, casting and rolling zone length: 75mm, nozzle thickness: 2-3mm, upper and lower nozzles staggered by 6mm.

[0086] Al-5Ti-1B wire is added to the channel before the degassing box. The addition of Al-Ti-B must not be stopped or interrupted. The amount added should be such that the total Ti element content reaches 0.02-0.05 wt.%.

[0087] Degassing is carried out stably at 730-740℃, with a rotor speed of 500 r / min and argon as the degassing medium.

[0088] The filter box uses two-stage filter plates of 30 mesh and 50 mesh.

[0089] The roll crown is 0.15 mm, the cooling water temperature in the roll is 30-35℃, the casting speed is 600 mm / min, and then the roll is wound up by a coiler to obtain the cast-rolled strip. Figure 2 shows the state and appearance of the obtained cast-rolled strip. As can be seen from Figure 2, the obtained cast-rolled strip has a good appearance and good coilability.

[0090] According to the forming requirements, a 2mm thick cast-rolled strip is cut into 2D sheets of the specified shape. The sheets are placed in a heating furnace and heated to 480℃ for 150 seconds. Then, within 10 seconds, the sheets are transferred from the heating furnace to a water-cooled quenching mold. After 2 seconds, the mold is closed and held under pressure for 10 seconds at a temperature of 40℃. The mold is then opened, the formed part is removed, and placed in a 170℃ heating furnace for aging treatment for 4 hours.

[0091] Figure 3 shows the metallographic structure of the cast-rolled strip after the casting and rolling process.

[0092] Figure 4 shows the metallographic structure of the parts after aging and baking.

[0093] As can be seen from Figures 3 and 4, the obtained aluminum alloy sheets and parts have a uniform microstructure, fine grains, and no segregation.

[0094] The tensile strength, yield strength, and elongation of the obtained parts were tested according to ASTM E8 / E8M, and the results are listed in Table 2.

[0095] Example 2

[0096] Example 2 is carried out with reference to Example 1, except that the aging process takes 0.5 hours.

[0097] The tensile strength, yield strength, and elongation of the obtained parts were tested according to ASTM E8 / E8M, and the results are listed in Table 2.

[0098] Example 3

[0099] Example 3 is carried out with reference to Example 1, except that the time for aging processing is 1 hour.

[0100] The tensile strength, yield strength, and elongation of the obtained parts were tested according to ASTM E8 / E8M, and the results are listed in Table 2.

[0101] Comparative Example 1

[0102] Comparing Example 1 with Example 1, the difference is that the aluminum alloy sheet is directly cold-stamped at room temperature (20°C).

[0103] The tensile strength, yield strength, and elongation of the obtained parts were tested according to ASTM E8 / E8M, and the results are listed in Table 2.

[0104] Table 2. Performance of aluminum alloy parts obtained in each embodiment

[0105] Comparative Example 2

[0106] Comparing Example 2 with Example 1, the difference is that the nozzle opening is 10mm and the length of the casting zone is 60mm.

[0107] During the experiment, a roller sticking phenomenon was discovered, resulting in plate failure and the inability to produce qualified cast-rolled plates, thus hindering subsequent component forming. Figures 5 and 6 show the morphology and appearance of the plates obtained after casting and rolling. As shown in Figures 5 and 6, the obtained plates have an uneven appearance, exhibit cracks, and cannot be rolled into coils.

[0108] While some aspects of the invention have been shown and discussed, those skilled in the art will recognize that changes can be made to these aspects without departing from the principles and spirit of the invention, and therefore the scope of the invention will be defined by the claims and their equivalents.

Claims

1. A method for processing aluminum alloy parts, characterized in that, include: Aluminum alloy raw materials are prepared into aluminum alloy coils through a casting and rolling process; and Aluminum alloy coils are formed into aluminum alloy parts through a hot stamping process. The casting and rolling process includes the following steps performed in sequence: smelting, electromagnetic stirring, slag removal, refining, furnace turning, settling, venting, online crystal refinement, degassing, filtration and slag removal, and casting and rolling. The online crystal refinement is achieved by adding a grain refiner. The amount of grain refiner added, relative to the total weight of the aluminum alloy, results in a titanium content of 0.02 wt.% - 0.1 wt.%. The nozzle opening for casting and rolling is 12-18mm, and the length of the casting and rolling zone reaches 70-90mm. The aluminum alloy raw material is selected from the 2xxx, 6xxx and 7xxx series aluminum alloy materials.

2. The method according to claim 1, characterized in that, The stamping process includes the following steps performed in sequence: cutting, heating, hot stamping, and artificial aging.

3. The method according to claim 1 or 2, characterized in that, The aluminum alloy raw material is a 6xxx series aluminum alloy material.

4. The method according to claim 1 or 2, characterized in that, The thickness of the aluminum alloy coil is 0.5-5mm.

5. The method according to claim 1 or 2, characterized in that, The grain refiner is an aluminum-titanium-boron grain refiner and / or an aluminum-titanium master alloy.

6. The method according to claim 1 or 2, characterized in that, The diameter of the casting rolls used in casting and rolling shall not be less than 900 mm, and the rolling force shall not be less than 20000 KN.

7. The method according to claim 1 or 2, characterized in that, The opening size of the casting nozzle used in casting and rolling is 12-15mm.

8. The method according to claim 1 or 2, characterized in that, The casting and rolling speed is in the range of 300-1100 mm / min, and / or the cooling rate is in the range of 100-300℃ / s.

9. The method according to claim 1 or 2, characterized in that, No solution treatment is performed before or during the hot stamping process.

10. The method of claim 2, characterized in that, In the hot stamping process, the heating temperature T1 of the sheet metal is in the range of 200 to 500°C, and the heating time of the cut sheet metal from room temperature to the heating temperature T1 is in the range of 0.5 to 15 minutes.

11. The method of claim 2, characterized in that, The temperature at which the molded parts are removed from the mold should not exceed 100℃.

12. The method of claim 2, characterized in that, The temperature for artificial aging during the hot stamping process is in the range of 100-200℃.

13. An aluminum alloy component, which is prepared by the method according to any one of claims 1-12.

14. An automobile comprising the aluminum alloy components according to claim 13.

Images