Aluminum alloy part, machining method thereof and automobile comprising aluminum alloy part

Abstract

The invention relates to an aluminum alloy part, a machining method thereof and an automobile comprising the aluminum alloy part. The machining method comprises the steps that an aluminum alloy coiled material is prepared from an aluminum alloy raw material through the cast rolling step, and the aluminum alloy coiled material is formed into the aluminum alloy part through the hot stamping step. According to the machining method of the aluminum alloy part, the production efficiency can be improved, and the production cost can be reduced. The obtained aluminum alloy part has good mechanical properties.

Description

Technical Field

[0001] The present invention belongs to the field of metal product processing, and specifically relates to an aluminum alloy component, a processing method thereof, and a car comprising the same. Background Art

[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 range and safety performance of electric vehicles, major automakers are increasingly using aluminum alloys.

[0004] The aluminum alloys that have been used in the automotive industry mainly include 2xxx (Al-Cu-Mg), 5xxx (Al-Mg), 6xxx (Al-Mg-Si) and 7xxx (Al-Zn-Mg-Cu) series. Among them, the 5xxx series aluminum alloy has excellent formability, the heat-treatable and strengthened 2xxx series aluminum alloy has high strength and good weldability and forgeability, the 6xxx series aluminum alloy has both good formability in T4 / T4P state and high paint aging hardening response ability (the increment of alloy yield strength before and after paint), and the 7xxx series aluminum alloy has 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 processing of high-strength aluminum alloy products, the manufacturing cost of aluminum alloy plates is high, and solid solution treatment is required in the hot stamping process, resulting in slow production pace and high overall cost.

[0007] In response to this situation, some manufacturers use aluminum alloy sheets produced by a long process of continuous hot rolling, and at the same time perform solid solution treatment on the sheets before hot stamping. However, this processing technology consumes a lot of energy and cannot effectively solve the problems of slow production rhythm and high cost.

[0008] Therefore, there is still a need in the art for a fast and cost-effective method for processing aluminum alloy products. Summary of the invention

[0009] The object of the present 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, there is provided a method for processing an aluminum alloy component, characterized by comprising: Prepare an aluminum alloy coil from an aluminum alloy raw material through a casting and rolling step; and The aluminum alloy coil is formed into aluminum alloy parts through a hot stamping step.

[0011] According to a second aspect of the present invention, there is provided an aluminum alloy component, which is prepared by the above processing method.

[0012] According to a third aspect of the present invention, there is provided an automobile comprising the above-mentioned aluminum alloy component.

[0013] The processing method of the aluminum alloy parts of the present invention can improve production efficiency and reduce production costs. The obtained aluminum alloy parts have good mechanical properties, such as a tensile strength of at least 270 MPa, a yield strength of at least 215 MPa, and an elongation of at least 13%. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present invention is described in conjunction with the accompanying drawings so that those skilled in the art can better understand the various features and advantages of the present invention, wherein: Figure 1 Schematic diagram of the temperature-time curve in the hot stamping step of the aluminum alloy parts processing method of the present invention is shown in FIG.

[0015] Figure 2 The metallographic structure of the cast strip after the casting process in Example 1 is shown.

[0016] Figure 3 The metallographic structure of the parts in Example 1 after aging baking is shown. DETAILED DESCRIPTION

[0017] The technical solution of the present invention is described in detail below.

[0018] According to a first aspect of the present invention, there is provided a method for processing an aluminum alloy component, characterized by comprising: Prepare an aluminum alloy coil from an aluminum alloy raw material through a casting and rolling step; and The aluminum alloy coil is formed into aluminum alloy parts through a hot stamping step.

[0019] The casting and rolling step can be carried out using a commonly used procedure in the art.

[0020] For example, the casting and rolling step may include the following processes performed in sequence: smelting-electromagnetic stirring-slagging-refining-tumbling-standing-discharging-online crystal refinement-degassing-filtration and deslagging-casting and rolling.

[0021] For example, the hot stamping step may include the following processes performed in sequence: cutting-heating-hot stamping-artificial aging.

[0022] The aluminum alloy raw material that can be processed by the method of the present invention can be any aluminum alloy material commonly used for processing automobile parts, such as an aluminum alloy material selected from 2xxx, 6xxx and 7xxx series, such as 6016.

[0023] The aluminum alloy coil may have a suitable thickness, for example, 0.5-5 mm.

[0024] Specifically, smelting includes melting the raw materials, sampling and testing the alloy composition, and adding different components as needed according to the alloy composition table for blending.

[0025] Smelting may be carried out in a smelting furnace at a temperature in the range of, for example, 720-760°C, preferably 740-750°C.

[0026] The deslagging agent used in the deslagging is a deslagging agent commonly used in the art.

[0027] Refining may be carried out at a temperature in the range of, for example, 730-770°C, preferably 740-745°C.

[0028] On-line crystal refinement is carried out by adding grain refiners.

[0029] Preferably, the grain refiner is an aluminum-titanium-boron alloy and / or an aluminum-titanium master alloy.

[0030] By adding grain refiners, preferably aluminum-titanium-boron alloys and aluminum-titanium master alloys, the grains can be refined and the macro-segregation of the ingot can be reduced, while avoiding increasing costs and causing new segregation.

[0031] Preferably, the grain refiner is added in an amount such that the titanium content reaches 0.02 wt.%-0.1 wt.%.

[0032] Preferably, the degassing is carried out at 730-740°C.

[0033] Preferably, the degassing medium is argon.

[0034] The casting rolls used in casting and rolling can be lubricated with graphite emulsion.

[0035] Preferably, the diameter of the casting roll used for casting 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.

[0036] Preferably, the opening of the casting nozzle used for casting and rolling is 12-18 mm, preferably 12-15 mm, and the length of the casting and rolling zone is not less than 65 mm, preferably 70-90 mm.

[0037] The inventors have found 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, the solidification rate of the molten metal can be increased, and the quality of the cast billet can be improved, especially segregation can be reduced.

[0038] Preferably, the casting speed is in the range of 300-1100 mm / min, more preferably in the range of 400-700 mm / min.

[0039] The inventors found that the generation of cracks was reduced by reducing the casting speed.

[0040] Preferably, the cast-rolled coil is cooled rapidly after casting and rolling to achieve a supersaturated solid solution effect, so as to facilitate subsequent forming.

[0041] Preferably, the cooling rate is in the range of 100-300° C. / s.

[0042] The inventors found that by increasing the cooling intensity and reducing the segregation phenomenon, the quality of the ingot is further improved.

[0043] In the hot stamping step, the coil is first cut into a specified shape, such as a two-dimensional (2D) shaped sheet.

[0044] Figure 1 Schematic diagram of the temperature-time curve in the hot stamping step of the aluminum alloy parts processing method of the present invention is shown in FIG.

[0045] refer to Figure 1 , the cut sheet is placed in a heating furnace and heated from room temperature to the formed component T1 ( Figure 1 0-a), and keep warm for a short time ( Figure 1 Then the sheet is taken out of the heating furnace and transferred to the mold ( Figure 1 bc), at this time the temperature of the sheet is T2, the press is closed to allow the sheet to be stamped into the mold cavity and held for a certain period of time ( Figure 1 cd), the drawn part is taken out from the die cavity, and then artificial aging is performed on the drawn part to improve the mechanical properties of the product by controlling the heating temperature and heating time.

[0046] In the processing method of the present invention, no solution treatment is performed before and during the hot stamping step.

[0047] Preferably, the heating temperature T1 of the sheet material in the hot stamping step is in the range of 200-500°C.

[0048] Preferably, the heating time a for heating the cut sheet from room temperature to the heating temperature T1 is in the range of 0.5-15 min.

[0049] Preferably, the sheet is transferred from the heating furnace to the mold within 15 seconds.

[0050] The mould may be equipped with a cooling system to cool the mould after the sheet has been formed.

[0051] Preferably, the temperature of the drawn part (ie, the formed part) when it is ejected from the mold is not higher than 100°C.

[0052] As used in this application, artificial aging means heating the formed part to an artificial hardening temperature and maintaining that temperature until precipitation hardening is allowed to occur.

[0053] Preferably, the temperature for artificial aging in the hot stamping step is in the range of 100-200°C.

[0054] Those skilled in the art can select the time required for artificial aging according to the aluminum alloy raw material.

[0055] The processing method of the aluminum alloy parts of the present invention can realize fast and cost-effective processing of aluminum alloy products.

[0056] The aluminum alloy parts obtained by the method of the present invention have good mechanical properties, for example, the tensile strength can reach at least 270 MPa, the yield strength can reach 215 MPa, and the elongation can reach at least 13%.

[0057] According to a second aspect of the present invention, there is provided an aluminum alloy component, which is prepared by the above processing method.

[0058] According to a third aspect of the present invention, there is provided an automobile comprising the above-mentioned aluminum alloy component.

[0059] The components may be structural parts such as B-pillar inner panels, B-pillar inner panel reinforcement plates, A-pillar inner panels, hinge reinforcement plates, floor beams, door inner panels, front and rear cover inner panels, floor skins, battery box cover panels and bottom guard panels, etc. In the present specification and claims, the nomenclature of aluminum alloys complies with the latest regulations of the Aluminum Association (The Aluminum Association) known in the art. And each alloy in each series has been registered with the Aluminum Association this year. For example, the aluminum alloys in the 2xxx series are called high-strength alloys and usually contain magnesium and copper as the main alloying elements. The alloys in the 6xxx and 7xxx series are also called high-strength alloys and are usually strengthened by heat treatment via precipitation of their main alloying elements, which are silicon and magnesium for the 6xxx series and copper, zinc and magnesium for the 7xxx series.

[0060] The terms “comprising” and “including” described in the present application encompass a case where the component is further comprised or includes other elements not explicitly mentioned as well as a case where the component is composed of the mentioned elements.

[0061] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the invention belongs. When the definition of a term in this specification conflicts with the meaning commonly understood by those skilled in the art to which the invention belongs, the definition described in this article shall prevail.

[0062] Unless otherwise indicated, all numerical values ​​expressing amounts of ingredients, temperature, and so forth used in the specification and claims are to be understood as being modified by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth herein are approximations that can vary depending upon the desired properties desired to be obtained.

[0063] Example The following will further illustrate the concept, specific structure and technical effects of the present invention in conjunction with the embodiments, so that those skilled in the art can fully understand the purpose, characteristics and effects of the present invention. It is not difficult for those skilled in the art to understand that the embodiments herein are only for illustrative purposes, and the scope of the present invention is not limited thereto. If not clearly stated, the raw materials used in the embodiments are those commonly used in the art.

[0064] Example 1 In this embodiment, aluminum alloy 6016 having the composition shown in Table 1 is used as the aluminum alloy raw material: Table 1 Si Mg Cu Mn Ti Fe Cr Zn Al 0.7 0.59 0.11 0.07 0.02-0.05 0.17 0.01 0.02 margin Follow the steps below to process the parts: Melting and electromagnetic stirring: according to the ratio shown in Table 1, pure aluminum ingots and intermediate aluminum alloys are added into the melting furnace, heated and melted into a melt. The melting process adopts electromagnetic stirring 2-3 times, each time for 5-10 minutes. When the temperature reaches 740-750℃, slag remover is added, stirred evenly and allowed to stand for 5-10 minutes, and then the slag is removed.

[0065] Composition adjustment: Take samples from the melt to quickly test the chemical composition, then add material and adjust the alloy composition to meet the composition table 1.

[0066] Refining, pouring, and standing: After the sampling test is qualified, it is refined twice, each time for 20-30 minutes. After refining, it is left to stand for 5-10 minutes to remove slag to ensure that there is no residue on the surface. The furnace is poured at a melt temperature of 740-745℃, and it is left to stand in a holding furnace at 730-735℃.

[0067] Vertical plate discharge, Al-5Ti-1B wire online addition, degassing, filtration, casting and rolling: Vertical plate slag running speed: 1300 ~ 1500mm / min, slag running time: 5min, casting nozzle opening 13mm, casting and rolling zone length 75mm, nozzle thickness 2-3mm, upper and lower nozzles staggered 6mm front and back.

[0068] Al-5Ti-1B wire is added into the flow channel before the degassing box. The addition of Al-Ti-B is not allowed to stop or be interrupted. The addition amount is such that the total Ti element content reaches 0.02-0.05 wt.%.

[0069] The degassing was carried out stably at 730-740°C, the rotor speed was 500r / min, and the degassing medium was argon.

[0070] The filter box uses 30 mesh and 50 mesh double-stage filter plates.

[0071] The roller convexity is 0.15 mm, the cooling water temperature in the roller is 30-35° C., the casting speed is 600 mm / min, and then the coiler is coiled to obtain the cast-rolled strip.

[0072] According to the forming requirements, the 2mm thick cast and rolled strip is cut into 2D sheets of specified shapes, and the sheets are placed in a heating furnace for heating. The heating temperature is set to 480°C and kept warm for 150 seconds. Then, within 10 seconds, the sheets are transferred from the heating furnace to a water-filled mold with a quenching function. The mold is closed after 2 seconds, and the pressure is maintained for 10 seconds after closing the mold. At this time, the mold temperature is 40°C. The mold is opened, the formed parts are taken out, and the parts are placed in a 170°C heating furnace for aging treatment for 4 hours.

[0073] Figure 2 The metallographic structure of the cast strip after the casting process is shown.

[0074] Figure 3 Shows the metallographic structure of the component after aging baking.

[0075] Figure 2 and Figure 3 It can be seen that the obtained aluminum alloy plates and parts have uniform structure, fine grains and no segregation.

[0076] The tensile strength, yield strength and elongation of the samples of the obtained parts were tested according to ASTM E8 / E8M, and the results are listed in Table 2.

[0077] Example 2 Example 2 was carried out with reference to Example 1, except that the aging treatment time was 0.5 hours.

[0078] The tensile strength, yield strength and elongation of the samples of the obtained parts were tested according to ASTM E8 / E8M, and the results are listed in Table 2.

[0079] Example 3 Example 3 was carried out with reference to Example 1, except that the aging treatment time was 1 hour.

[0080] The tensile strength, yield strength and elongation of the samples of the obtained parts were tested according to ASTM E8 / E8M, and the results are listed in Table 2.

[0081] Comparative Example 1 Comparative Example 1 is carried out with reference to Example 1, except that the aluminum alloy sheet is directly cold stamped at room temperature (20°C).

[0082] The tensile strength, yield strength and elongation of the samples of the obtained parts were tested according to ASTM E8 / E8M, and the results are listed in Table 2.

[0083] Table 2. Properties of aluminum alloy parts obtained in each example Example Tensile strength(MPa) Yield strength(MPa) Elongation(%) 1 325 299 13.1 2 277 219 20.06 3 307 263 16.2 Comparison 1 302 292 6.82 Although some aspects of the present invention have been shown and discussed, it will be appreciated by those skilled in the art that changes may be made to the above aspects without departing from the principles and spirit of the invention, and the scope of the invention shall be defined by the claims and their equivalents.

Claims

1. A method for processing aluminum alloy parts, characterized in that: include: The aluminum alloy raw material is used to prepare an aluminum alloy coil through a casting and rolling step; and The aluminum alloy coil is formed into aluminum alloy parts through a hot stamping step.

2. The method according to claim 1, characterized in that The casting and rolling step includes the following steps performed in sequence: smelting - electromagnetic stirring - slagging - refining - pouring - standing - discharge - online crystal refinement - degassing - filtering and deslagging - casting and rolling, and / or The hot stamping step includes the following processes performed in sequence: cutting-heating-hot stamping-artificial aging.

3. The method according to claim 1, characterized in that The aluminum alloy raw material is an aluminum alloy material selected from 2xxx, 6xxx and 7xxx series.

4. The method according to claim 2, characterized in that: The on-line crystal refinement is performed by adding a grain refiner.

5. The method according to claim 4, 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 4 or 5, characterized in that: The grain refiner is added in an amount such that the titanium content reaches 0.02 wt.%-0.1 wt.% relative to the total weight of the aluminum alloy.

7. The method according to claim 2, characterized in that: The diameter of the casting roll used for casting and rolling shall not be less than 900mm, and the rolling force shall not be less than 20000KN.

8. The method according to claim 2, characterized in that: The opening of the casting nozzle used for casting and rolling is 12-18mm, and the length of the casting and rolling zone reaches 70-90mm.

9. The method according to claim 2, characterized in that: The casting speed is in the range of 300-1100 mm / min.

10. The method according to claim 1 or 2, characterized in that: No solution treatment was performed before and during the hot stamping step.

11. The method according to claim 2, characterized in that In the hot stamping step, the heating temperature T1 of the sheet is in the range of 200-500° C., and the heating time for heating the cut sheet from room temperature to the heating temperature T1 is in the range of 0.5-15 min.

12. The method according to claim 2, characterized in that: The temperature of the molded parts is not higher than 100℃.

13. The method according to claim 2, characterized in that The temperature for artificial aging during the hot stamping step is in the range of 100-200°C.

14. An aluminum alloy component manufactured by the method according to any one of claims 1 to 13.

15. An automobile comprising the aluminum alloy component according to claim 14.

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