Preparation process of remelted aluminum alloy round bar

Abstract

The invention provides a preparation process of a remelted aluminum alloy round bar, and relates to the field of aluminum alloy casting, the remelted aluminum alloy round bar comprises an aluminum ingot, a bar head tail material and an extrusion waste material, and the raw materials comprise, by weight, 85%-95% of the aluminum ingot, 2.5%-7.5% of the bar head tail material and 2.5%-7.5% of the extrusion waste material. The rod head tail material and the extrusion waste material which are properly introduced contain tiny and dispersively distributed second phase mass points, and the mass points serve as effective heterogeneous nucleation cores and promote non-spontaneous nucleation of crystal grains in the solidification process of aluminum alloy melt, so that the crystal grain size of a casting structure is refined, the casting structure is finer and more uniform, and the casting quality is improved. And a fine grain structure is beneficial to improving the plasticity, toughness and attractiveness of subsequent surface treatment of the aluminum alloy, and the overall quality and performance stability of a final product are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of aluminum alloy casting, in particular to a preparation process of remelted aluminum alloy round bar. BACKGROUND

[0002] With the continuous upgrading of the demand for lightweight vehicles, 6060 aluminum alloy has gradually become a key material due to its high strength and excellent corrosion resistance; however, its traditional homogenization process still has significant defects. On the one hand, the use of single-stage heating method easily leads to coarse grains, resulting in a pass rate of only about 60% for macrostructure, which seriously affects the consistency of material performance. On the other hand, this process needs to rely on high-purity aluminum ingots (with iron content ≤0.031%) as raw materials, resulting in a high proportion of raw material costs, which restricts its economy.

[0003] Although the prior art has been committed to optimizing the heat treatment system or adjusting the alloy composition, it generally ignores the potential nucleation value of micron-sized intermetallic compounds in recycled aluminum, and fails to effectively utilize their characteristics of promoting fine grain formation, thus unable to achieve grain refinement control while reducing the dependence on high-purity raw materials, resulting in the problem that cost and performance are difficult to improve simultaneously. SUMMARY

[0004] The present application aims to provide a preparation process of remelted aluminum alloy round bar to solve the problems of high production cost, serious resource waste and potential non-uniform grain structure in the existing 6060 aluminum alloy production process, and to provide a remelted aluminum alloy round bar with lower cost, higher resource utilization rate and excellent performance.

[0005] To solve the above technical problems, the present application adopts the following technical solutions: A remelted aluminum alloy round bar, comprising aluminum ingots, rod head and tail materials, and extrusion waste materials, the raw materials comprising, by weight percentage, 85-95% of aluminum ingots, 2.5-7.5% of rod head and tail materials, and 2.5-7.5% of extrusion waste materials.

[0006] Preferably, the raw materials comprise, by weight percentage, 90% of aluminum ingots, 5% of rod head and tail materials, and 5% of extrusion waste materials.

[0007] Preferably, the aluminum ingots comprise the following elements by weight percentage: Si 0.0370%, Fe 0.0677%, Cu <0.0002%, Mn 0.00067%, Mg <0.0010%, Zn 0.0090%, Cr <0.0010%, Ti <0.0010%, and the balance being Al. The bar head and tail materials contain the following elements by weight percentage: Si 0.430%, Fe 0.0631%, Cu 0.0682%, Mn 0.0836%, Mg <0.589%, Zn 0.0032%, Cr <0.0371%, Ti <0.0389%, with the balance being Al; The extrusion waste comprises the following elements by weight percentage: Si 0.393%, Fe 0.121%, Cu <0.0002%, Mn 0.0024%, Mg 0.506%, Zn <0.0010%, Cr <0.0010%, Ti <0.0069%, with the balance being Al.

[0008] A process for preparing remelted aluminum alloy round bars, the process including the following steps: S1: Prepare aluminum ingots, bar end stock and extrusion waste according to the proportions of claim 1 or 2; S2: The raw materials prepared in step S1 are put into the melting furnace for melting to obtain aluminum alloy melt; S3: Refining and casting the aluminum alloy melt to obtain aluminum alloy casting rods; S4: The aluminum alloy casting rod is homogenized.

[0009] Preferably, in step S2, the melting temperature is 720°C to 760°C.

[0010] Preferably, in step S3, the refining process includes slag removal, degassing, and filtration.

[0011] Preferably, the filtration process employs a two-stage filtration method, retaining particles with a diameter of 0.5μm to 2μm in the aluminum alloy melt as nucleation nuclei.

[0012] Preferably, in step S4, the homogenization process includes linearly heating to 560°C and then maintaining the temperature at that temperature for a sufficient duration.

[0013] The beneficial effects of this invention are: 1. This invention directly reduces the raw material cost per unit product by introducing 10% of its own recycled materials to replace an equal amount of virgin aluminum ingots. Since the recycled materials originate from within the production process, their acquisition cost is much lower than that of commercially available virgin aluminum ingots, resulting in significant economic benefits.

[0014] 2. The present invention introduces a suitable amount of bar tail and extrusion waste containing tiny, dispersed second-phase particles. These particles act as effective heterogeneous nucleation nuclei during the solidification of the aluminum alloy melt, promoting non-spontaneous nucleation of grains, thereby refining the grain size of the casting structure, making it smaller and more uniform. The fine grain structure is beneficial to improving the plasticity, toughness and aesthetics of the aluminum alloy and subsequent surface treatment, thus improving the overall quality and performance stability of the final product. Attached Figure Description

[0015] Figure 1 High-magnification image of aluminum alloy round bars prepared using traditional techniques; Figure 2 This application yields a high-magnification image of a remelted aluminum alloy round bar; Detailed Implementation

[0016] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0017] Unless otherwise defined, 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. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0018] Example 1 This embodiment proposes a process for preparing remelted aluminum alloy round bars, including the following steps: 1) Weigh the following raw materials by weight percentage: 90% aluminum ingots, 5% of the 6060 alloy bar head and tail material produced by our factory (after surface cleaning treatment), and 5% of the 6060 alloy extrusion scrap produced by our factory (after baling and surface cleaning treatment). For example, for a total furnace charge of 1000kg, weigh 900kg aluminum ingots, 50kg bar head and tail material and 50kg extrusion scrap.

[0019] 2) Add the above raw materials to an industrial frequency melting furnace and heat them to 740±10℃ to completely melt them into an aluminum alloy melt. During this process, add elements such as Mg and Si as needed to ensure that the final composition meets the 6060 aluminum alloy standard.

[0020] 3) The aluminum alloy melt at 740℃ is refined by first removing slag, then passing high-purity argon gas for rotary degassing, and adding sodium-free refining agent to control the hydrogen content in the melt to below 0.15mL / 100g Al. Subsequently, the melt passes through a set of two-stage ceramic foam filter plates and enters a semi-continuous casting machine to cast aluminum alloy rods.

[0021] 4) After casting and cooling, the aluminum alloy ingot is sent into a homogenization furnace and heated to 560°C at a rate of 50°C / h. It is then kept at this temperature for 8 hours. After the holding period, the ingot is removed and forced to cool to room temperature.

[0022] Comparative Example 1 A comparative example of a process for preparing remelted aluminum alloy round bars includes the following steps: 1) Weigh the following raw materials by weight percentage: 100% aluminum ingots; 2) Add the above raw materials to an industrial frequency melting furnace and heat them to 740±10℃ to completely melt them into an aluminum alloy melt. During this process, add elements such as Mg and Si as needed to ensure that the final composition meets the 6060 aluminum alloy standard.

[0023] 3) The aluminum alloy melt at 740℃ is refined by first removing slag, then passing high-purity argon gas for rotary degassing, and adding sodium-free refining agent to control the hydrogen content in the melt to below 0.15mL / 100g Al. Subsequently, the melt passes through a set of two-stage ceramic foam filter plates and enters a semi-continuous casting machine to cast aluminum alloy rods.

[0024] 4) After casting and cooling, the aluminum alloy ingot is sent into a homogenization furnace and heated to 560°C at a rate of 50°C / h. It is then kept at this temperature for 8 hours. After the holding period, the ingot is removed and forced to cool to room temperature.

[0025] The homogenized aluminum alloy casting samples obtained in Example 1 and Comparative Example 1 were respectively subjected to the following tests: Table 1: Test Data Table Please see Figure 2 and with Figure 1 For reference, in Example 1, Al8Fe2Si nucleation cores were detected at the grain boundaries of the aluminum alloy casting rod. No abnormal grain growth was observed in the high-magnification structure. Through external verification, the measured Fe content was 0.0651%, and the uniformity of nucleation core distribution was >95%.

[0026] Please refer to Table 1 for data. The aluminum alloy casting obtained in Example 1 shows significantly finer and more uniform grains. This is because the trace dispersed phase particles present in the introduced rod head and tail material and extrusion waste act as heterogeneous nucleation sites, increasing the nucleation rate and inhibiting grain growth. Thanks to the grain refinement (fine grain strengthening effect), the aluminum alloy prepared in Example 1 has strength comparable to or even slightly surpasses that of conventional processes, while its plasticity (elongation after fracture) is significantly improved. This means that the aluminum alloy produced using the technology of this invention is not only cheaper but may also have better processing performance and toughness.

[0027] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0028] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A remelted aluminum alloy round bar, characterized by, The raw materials include aluminum ingots, rod head tail materials and extrusion waste materials, and the raw materials include, by weight percentage, 85-95% aluminum ingots, 2.5-7.5% rod head tail materials and 2.5-7.5% extrusion waste materials.

2. A remelted aluminum alloy round bar according to claim 1, wherein The raw materials include, by weight percentage, 90% aluminum ingots, 5% rod head tail materials and 5% extrusion waste materials.

3. A remelted aluminum alloy round bar according to claim 2, wherein The aluminum ingots include, by weight percentage, Si 0.0370%, Fe 0.0677%, Cu <0.0002%, Mn 0.00067%, Mg <0.0010%, Zn 0.0090%, Cr <0.0010%, Ti <0.0010%, and the balance being Al. The rod head tail materials include, by weight percentage, Si 0.430%, Fe 0.0631%, Cu 0.0682%, Mn 0.0836%, Mg <0.589%, Zn 0.0032%, Cr <0.0371%, Ti <0.0389%, and the balance being Al. The extrusion waste materials include, by weight percentage, Si 0.393%, Fe 0.121%, Cu <0.0002%, Mn 0.0024%, Mg 0.506%, Zn <0.0010%, Cr <0.0010%, Ti <0.0069%, and the balance being Al.

4. A process for producing a remelted aluminum alloy round bar, characterized by, The process includes the step of batching the raw materials according to claim 1 or 2.

5. The manufacturing process of claim 4, wherein, The process includes the following steps: S1: preparing aluminum ingots, rod head tail materials and extrusion waste materials according to the proportions of claim 1 or 2; S2: melting the raw materials prepared in step S1 in a melting furnace to obtain an aluminum alloy melt; S3: refining and casting the aluminum alloy melt to obtain an aluminum alloy cast rod; S4: homogenizing the aluminum alloy cast rod.

6. The manufacturing process of claim 5, wherein: In step S2, the melting temperature is 720-760°C.

7. The production process according to claim 5 or 6, characterized in that: In step S3, the refining includes skimming, degassing and filtering treatment.

8. The manufacturing process of claim 7, wherein: The filtering treatment uses double-stage filtering, and retains particles with a particle size of 0.5-2 μm in the aluminum alloy melt as nucleation cores.

9. The manufacturing process of claim 5, wherein: In step S4, the homogenizing treatment includes linearly heating to 560°C and then maintaining the temperature for a sufficient length of time.

10. A remelted aluminum alloy round rod prepared by the preparation process of any one of claims 4-9.

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