Ultrahigh-strength aluminum alloy extruded profile and preparation method thereof

Abstract

The invention belongs to the technical field of aluminum alloy extruded profiles, and relates to an ultrahigh-strength aluminum alloy extruded profile and a preparation method thereof. By adjusting the component proportion of the 3-series aluminum alloy, especially the proportion of manganese (Mn) and silicon (Si), sufficient mechanical strength can be obtained without an additional cold drawing process after extrusion forming, so that the yield is directly improved, and the production cost is reduced. The 3-series aluminum alloy profile produced through the preparation method has excellent mechanical properties including the tensile strength larger than or equal to 140 MPa, the yield strength larger than or equal to 110 MPa and the ductility A50 larger than or equal to 10%, and the characteristics are crucial for guaranteeing the safety and reliability of energy storage equipment.

Description

Technical Field

[0001] The invention belongs to the technical field of aluminum alloy extruded profiles and relates to an ultra-high-strength aluminum alloy extruded profile and a preparation method thereof. Background Art

[0002] With the booming development of the energy storage industry, heat exchangers and tanks are key components in energy storage systems, and their material selection is particularly important. In recent years, 3 series aluminum alloys have gradually become the mainstream choice for products such as battery core shells and heat exchangers due to their unique advantages. This aluminum alloy not only has significant lightweight advantages, which enables energy storage equipment to reduce weight while increasing energy density, but also its excellent recyclability makes resources more efficiently utilized, reduces production costs and improves the environmental friendliness of the product.

[0003] In addition, the extrudability of 3 series aluminum alloy enables it to meet the needs of different energy storage devices through various molding processes, while its high corrosion resistance ensures the stable operation of the equipment in complex environments. More importantly, this aluminum alloy also has efficient heat dissipation performance, which helps to keep the battery cell within a suitable operating temperature range, thereby improving the performance and safety of energy storage equipment.

[0004] However, the existing 3 series aluminum alloys still have some shortcomings in practical applications, especially in the manufacturing process of battery shell products. At present, the application of 3 series aluminum alloy extruded profiles in battery shell products requires cold drawing to improve the strength due to the insufficient strength after extrusion molding, which not only increases the production process, greatly reduces the yield rate, but also pushes up the product cost. In addition, there are two process routes for producing battery shell products, namely "rolling + rolling + welding" and "rolling + stamping". The former requires welding, which makes the weld on the battery shell a weak point, easily causing the risk of battery leakage and explosion-proof cracking, which is difficult to solve fundamentally; the latter is due to the limitations of the stamping process itself, and there is a problem that the product length is limited and the special-shaped battery shells with different wall thicknesses cannot be produced. These problems limit the wide application of 3 series aluminum alloys in the field of energy storage and affect the overall performance and safety of energy storage equipment. Therefore, the present invention aims to solve the deficiencies in the prior art by improving the material formula and preparation process, and provide a more efficient, economical and reliable solution to meet the demand for high-performance materials in the energy storage industry and promote the further development of energy storage technology. Summary of the invention

[0005] The purpose of the present invention is to address the above-mentioned problems existing in the prior art and to propose a high-strength aluminum alloy extruded profile for energy storage devices which does not require cold drawing after extrusion and whose strength can meet product requirements.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] An ultra-high strength aluminum alloy extruded profile, wherein the aluminum alloy extruded profile raw material is composed of the following elements in percentage by mass: 0.35-0.80% Si, 0.9-1.60% Mn, 0.10-0.70% Fe, Cu≤0.20%, and the remainder is Al and other inevitable impurity elements.

[0008] In the above-mentioned ultra-high strength aluminum alloy extruded profile, preferably, the aluminum alloy extruded profile raw material is composed of the following elements in percentage by mass: 0.40-0.65% Si, 1.2-1.55% Mn, 0.20-0.40% Fe, Cu≤0.20%, and the remainder is Al and other unavoidable impurity elements.

[0009] In the above-mentioned ultra-high strength aluminum alloy extruded profile, preferably, the contents of Mn and Si satisfy:

[0010] 2.0wt%≤1.5Mn+Si≤3.0wt%, 1.5≤Mn / Si≤3

[0011] The present invention also provides a method for preparing the ultra-high strength aluminum alloy extruded profile, the method comprising the following steps:

[0012] S1. Prepare raw materials;

[0013] S2, melting and casting the raw materials into aluminum bars, and then homogenizing them;

[0014] S3, then preheating the aluminum rod, and then using a hot extrusion die to make an extruded profile;

[0015] S4. Quench the extruded profile and straighten it after cooling to room temperature.

[0016] In the above-mentioned method for preparing an ultra-high-strength aluminum alloy extruded profile, the homogenization treatment temperature is 300-600° C. and the time is 8-48 hours.

[0017] In the above-mentioned method for preparing an ultra-high strength aluminum alloy extruded profile, the preheating temperature is 450-540°C.

[0018] In the above-mentioned method for preparing an ultra-high-strength aluminum alloy extruded profile, the extrusion ratio is 20-100.

[0019] In the above-mentioned method for preparing an ultra-high strength aluminum alloy extruded profile, the quenching temperature is 450-560°C.

[0020] In the above-mentioned method for preparing an ultra-high strength aluminum alloy extruded profile, the cooling in step S4 is performed by air or wind cooling.

[0021] In the above-mentioned method for preparing an ultra-high strength aluminum alloy extruded profile, the straightening rate in step S4 is 0.5-3%.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The present invention adjusts the composition ratio of the 3 series aluminum alloy, especially the ratio of manganese (Mn) and silicon (Si), so that sufficient mechanical strength can be obtained without an additional cold drawing process after extrusion molding, which directly improves the yield and reduces the production cost.

[0024] 2. The 3 series aluminum alloy profiles produced by the preparation method of the present invention have excellent mechanical properties, including tensile strength ≥140MPa, yield strength ≥110MPa, and elongation A50 ≥10%, which are crucial to ensuring the safety and reliability of energy storage equipment.

[0025] 3. The present invention makes the alloy material have good extrudability by precisely controlling the content of Mn and Si and reasonably setting the content of Fe and Cu, and can realize the forming of complex shapes without sacrificing strength. DETAILED DESCRIPTION

[0026] The following are specific embodiments of the present invention, which further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.

[0027] The 3 series aluminum alloy of the present invention is composed of the following elements in percentage by mass:

[0028] Si: 0.35~0.80%; Cu: ≤0.20%; Mn: 0.90~1.60%; Fe: 0.10~0.70%; other unavoidable impurity elements, single impurity: ≤0.05%, total impurities: ≤0.15%; the rest is Al.

[0029] Among them, as a preferred embodiment, 2.0wt.%≤1.5Mn+Si≤3.0wt.%, 1.5≤Mn / Si≤3.

[0030] Mn is the main additive element of the 3 series alloy, mainly forming the Al6Mn second phase. In the presence of Si, it can promote the precipitation of high-density submicron-scale Al-Mn-Si-based dispersed phase on the alloy matrix, which can effectively improve the strength of the alloy.

[0031] When Mn is less than 0.90wt%, the strengthening effect is insufficient, and when the Mn content exceeds 1.6wt%, the plasticity deteriorates, the extrudability decreases and it is difficult to produce. Therefore, the appropriate range of Mn is 0.90-1.6wt%.

[0032] When Si is less than 0.35wt%, the strengthening effect is insufficient, and when the Si content exceeds 0.80wt%, the strengthening effect is too high, the alloy becomes hard, the extrudability decreases and it is difficult to produce. Therefore, the appropriate range of Si is 0.35-0.80wt%.

[0033] The present invention finds through theoretical analysis and a large amount of data verification and summary that when Mn and Si satisfy the relationship of 2.0wt.%≤1.5Mn+Si≤3.0wt.%, 1.5≤Mn / Si≤3, the strengthening potential of Mn and Si can be maximized.

[0034] Fe is an impurity element in 3 series aluminum alloys, which is not good for the plasticity and extrudability of the material. When Fe is less than 0.10wt%, it is not recommended because the high purity will increase the product cost. When Fe is greater than 0.7wt%, a coarse Al-(Fe, Mn)-Si-based crystal phase will be formed in the alloy during casting, and the plasticity will deteriorate and the extrudability will decrease. Therefore, the appropriate range of Fe is 0.10-0.7wt%.

[0035] Cu can produce solid solution strengthening in 3 series aluminum alloys as supplementary strengthening. At the same time, the presence of trace amounts of Cu can also promote the transformation of material corrosion from pitting corrosion to uniform corrosion. When the Cu content exceeds 0.20wt%, the intergranular corrosion performance deteriorates. Therefore, the appropriate range of Cu is ≤0.20wt%.

[0036] Embodiment 1-11:

[0037] S1. The aluminum alloy profile compositions of Examples 1-11 are configured as shown in Table 1;

[0038] S2. Add the prepared alloy raw materials into a smelting furnace and smelt them at 810°C to make them all melt into liquid to form aluminum melt. After they are all melted into liquid, keep them warm for about half an hour to remove slag and refine the aluminum melt. After the components are adjusted to the required standard, reduce the temperature of the aluminum melt to 730°C, and perform standing, slag removal and casting in sequence to obtain round cast bars, and then perform homogenization treatment at 450°C for 8 hours.

[0039] S2, then preheating the aluminum rod at 515°C, and then using a hot extrusion die to produce an extruded profile with an extrusion ratio of 55;

[0040] S3. The extruded profile is then quenched at 530°C, then air-cooled to room temperature, and finally straightened, wherein the straightening rate is 1.0%.

[0041] Comparative Examples 1-3:

[0042] S1. The aluminum alloy profile compositions of Comparative Examples 1-3 are configured as shown in Table 1;

[0043] S2. Add the prepared alloy raw materials into a smelting furnace and smelt them at 780°C to make them all melt into liquid to form aluminum melt. After they are all melted into liquid, keep them warm for about half an hour to remove slag and refine the aluminum melt. After the components are adjusted to the required standard, reduce the temperature of the aluminum melt to 720°C, and perform standing, slag removal and casting in sequence to obtain round cast bars, and then perform homogenization treatment at 450°C for 8 hours.

[0044] S2, then preheating the aluminum rod at 515°C, and then using a hot extrusion die to produce an extruded profile with an extrusion ratio of 55;

[0045] S3. The extruded profile is then quenched at 530°C, then air-cooled to room temperature, and finally straightened, wherein the straightening rate is 1.0%.

[0046] Table 1: Elemental composition of aluminum alloy profiles prepared in Examples 1-11 and Comparative Examples 1-3

[0047]

[0048] Table 2: Performance test results of aluminum alloy profiles prepared in Examples 1-11 and Comparative Examples 1-3

[0049]

[0050]

[0051] The extrusion pressure of 280 bar is the upper limit of the equipment. If the breakthrough pressure reaches 280 bar, it can basically be judged that it does not have the capacity for industrial production.

[0052] The aluminum alloy profiles in Examples 1-11 use the composition formula and preparation method within the scope of the present invention. As can be seen from Table 2, the mechanical properties and extrudability can achieve the effects to be achieved by the present invention and meet the requirements of industrial production.

[0053] Among them, the mechanical properties of Examples 5-11 are relatively high, and the extrudability and industrial production capacity are also very high (the breakthrough pressure during extrusion is all <265 bar), and have outstanding comprehensive performance. Compared with Examples 1-4, the 1.5Mn+Si values ​​of the aluminum alloy profile raw materials in Examples 5-11 are all between 2 and 3. The composition design within this range is conducive to achieving good mechanical properties and ensuring the processing performance of the material; at the same time, the Mn / Si ratio is also relatively reasonable, between 1.5 and 3, which contributes to the synergistic effect between Mn and Si and effectively improves the comprehensive performance of the material.

[0054] In Comparative Examples 1 and 2, Si and Mn are respectively less than the lower limit of the present invention, which indicates that the contents of Mn and Si are relatively low and insufficient to provide sufficient strengthening effect, resulting in the mechanical properties (Rm, R0.2) of these samples being lower than those of the embodiments. In Comparative Example 3, the contents of Mn and Si exceed the upper limit of the present invention. Although the material has higher mechanical properties (especially Rm and R0.2), the breakthrough pressure reaches 280 bar, which is the upper limit of the equipment, indicating that the material has poor extrudability and is not suitable for large-scale industrial production.

[0055] In summary, the 3 series aluminum alloy profiles produced by the preparation method of the present invention have excellent mechanical properties, including tensile strength ≥140MPa, yield strength ≥110MPa, and elongation A50 ≥10%, which are crucial to ensuring the safety and reliability of energy storage equipment.

[0056] The parts of the embodiments herein that are not exhaustive of the midpoint values ​​of the technical scope claimed for protection by the present invention and the new technical solutions formed by equivalent replacement of single or multiple technical features in the technical solutions of the embodiments are also within the scope claimed for protection by the present invention; at the same time, in all the listed or unlisted embodiments of the scheme of the present invention, each parameter in the same embodiment merely represents an example of its technical solution (i.e., a feasible solution), and there is no strict coordination and limitation relationship between the parameters, wherein the parameters can be replaced with each other without violating the axioms and the claims of the present invention, unless otherwise stated.

[0057] The technical means disclosed in the scheme of the present invention are not limited to the technical means disclosed in the above technical means, but also include technical schemes composed of any combination of the above technical features. The above is a specific implementation of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications are also regarded as the protection scope of the present invention.

[0058] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. An ultra-high strength aluminum alloy extruded profile, characterized in that: The aluminum alloy extrusion profile raw material is composed of the following elements in percentage by mass: 0.35-0.80% Si, 0.9-1.60% Mn, 0.10-0.70% Fe, Cu≤0.20%, and the remainder is Al and other inevitable impurity elements.

2. The ultra-high strength aluminum alloy extruded profile according to claim 1, characterized in that: The aluminum alloy extrusion profile raw material is composed of the following elements in percentage by mass: 0.40-0.65% Si, 1.2-1.55% Mn, 0.20-0.40% Fe, Cu≤0.20%, and the remainder is Al and other inevitable impurity elements.

3. A high-strength aluminum alloy extruded profile for an energy storage device according to claim 1 or 2, characterized in that: The contents of Mn and Si must satisfy the following requirements: 2.0wt%≤1.5Mn+Si≤3.0wt%, 1.5≤Mn / Si≤3.

4. A method for preparing the ultra-high strength aluminum alloy extruded profile according to claim 1 or 2, characterized in that: The method comprises the following steps: S1. Prepare raw materials; S2, melting and casting the raw materials into aluminum bars, and then homogenizing them; S3, then preheating the aluminum rod, and then using a hot extrusion die to make an extruded profile; S4. Quench the extruded profile and straighten it after cooling to room temperature.

5. The method for preparing an ultra-high strength aluminum alloy extruded profile according to claim 4, characterized in that: The homogenization temperature in step S2 is 300-600°C and the time is 8-48h.

6. The method for preparing an ultra-high strength aluminum alloy extruded profile according to claim 4, characterized in that: The preheating temperature in step S3 is 450-540°C.

7. The method for preparing an ultra-high strength aluminum alloy extruded profile according to claim 4, characterized in that: The extrusion ratio of step S3 is 20-100.

8. The method for preparing an ultra-high strength aluminum alloy extruded profile according to claim 4, characterized in that: The quenching temperature in step S4 is 450-560°C.

9. The method for preparing an ultra-high strength aluminum alloy extruded profile according to claim 4, characterized in that: In step S4, cooling is performed by air or wind cooling.

10. The method for preparing an ultra-high strength aluminum alloy extruded profile according to claim 4, characterized in that: The straightening rate in step S4 is 0.5-3%.

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