Aluminum alloy casting, method for casting aluminum alloy casting, and machine tool

Abstract

The invention discloses an aluminum alloy casting, a casting method of the aluminum alloy casting and a machine tool. The aluminum alloy casting comprises the following components in percentage by mass: 9.0%-9.5% of zinc, 9.0%-9.5% of aluminum, 9.0%-9.5% of silicon and the balance of magnesium. The mass percent of the aluminum is 80.84%-82.74%; the mass percent of the silicon is 7.5%-8.5%; the mass percent of the magnesium is 0.4%-0.6%. According to the aluminum alloy casting, the casting method of the aluminum alloy casting and the machine tool, at least the problem that in the prior art, the large-size and high-strength aluminum alloy casting is difficult to manufacture can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of metal materials, and in particular to an aluminum alloy casting, a casting method of the aluminum alloy casting and a machine tool. Background Art

[0002] Aluminum alloys are widely used due to their low density, light weight, easy processing and excellent economy.

[0003] Cast aluminum alloys can be directly used to obtain aluminum alloys and aluminum alloy castings of parts by metal casting forming process. The alloy element content of this type of alloy is generally higher than that of the corresponding deformed aluminum alloy. The existing cast aluminum alloy is mainly aluminum silicon alloy, which is composed of Al, Si, Cu, and Mg. When higher strength and better cutting performance are required, heat treatment is required to meet the above requirements.

[0004] In some machine tool structures, aluminum alloy castings are usually used to prepare relatively long beam structures. For example, in some laser cutting machines, the beam used to support the laser cutting tool is usually required to be more than 4 meters. However, there is no heat treatment furnace in the prior art that can accommodate aluminum alloy castings longer than 4 meters, making it difficult to produce large-size, high-strength aluminum alloy beams that meet the needs of machine tools. Summary of the invention

[0005] The main purpose of the present invention is to provide an aluminum alloy casting, a casting method for the aluminum alloy casting and a machine tool, which at least solves the problem that it is difficult to manufacture large-size, high-strength aluminum alloy castings in the prior art.

[0006] According to one aspect of the present invention, there is provided an aluminum alloy casting, the components of the aluminum alloy casting comprising:

[0007] Zinc, aluminum, silicon, and magnesium, wherein the mass percentage of zinc is 9.0%-9.5%; the mass percentage of aluminum is 80.84%-82.74%; the mass percentage of silicon is 7.5%-8.5%; and the mass percentage of magnesium is 0.4%-0.6%.

[0008] Furthermore, the aluminum alloy casting also includes at least one of erbium, zirconium and titanium.

[0009] Furthermore, the mass percentage of erbium is 0.1%-0.15%.

[0010] Furthermore, the mass percentage of zirconium is 0.1%-0.2%.

[0011] Furthermore, the mass percentage of titanium is 0.05%-0.1%.

[0012] Further, the impurities in the aluminum alloy casting include iron, copper and manganese;

[0013] Wherein, the mass percentage of iron is less than or equal to 0.1%; the mass percentage of copper is less than or equal to 0.001%; ​​and the mass percentage of manganese is less than or equal to 0.0001%.

[0014] Furthermore, the tensile strength Rm of the aluminum alloy casting satisfies the relationship: Rm≥270MPa.

[0015] Furthermore, the elongation δ of the aluminum alloy casting satisfies the relationship: 5%≤δ≤8%.

[0016] On the other hand, the present application also provides a casting method of an aluminum alloy casting, including the above-mentioned aluminum alloy casting, and the casting method of the aluminum alloy casting comprises the following steps:

[0017] S1: Smelting in a crucible to obtain an aluminum alloy solution, wherein the main components of the aluminum alloy solution include zinc, silicon, magnesium, aluminum, erbium, zirconium and titanium, wherein the mass percentage of zinc is 9.0%-9.5%; the mass percentage of aluminum is 80.84%-82.74%; the mass percentage of silicon is 7.5%-8.5%; the mass percentage of magnesium is 0.4%-0.6%; the mass percentage of erbium is 0.1%-0.15%; the mass percentage of zirconium is 0.1%-0.2%; and the mass percentage of titanium is 0.05%-0.1%;

[0018] S2: injecting the aluminum alloy solution having a predetermined temperature at a predetermined speed to fill the mold;

[0019] S3: maintaining the mold filled with the aluminum alloy solution at a first predetermined pressure for a first predetermined time so that the aluminum alloy solution solidifies to form a crust, then maintaining the mold filled with the aluminum alloy solution at a second predetermined pressure for a second predetermined time so that the aluminum alloy solution in the crust crystallizes, and finally maintaining the aluminum alloy solution in the mold for a third predetermined time so that the aluminum alloy solution forms a solid casting.

[0020] Furthermore, the predetermined temperature in step S2 is 660°C-680°C.

[0021] Furthermore, the predetermined speed in step S2 is 40 mm / s-50 mm / s.

[0022] Further, the first predetermined time in step S3 is 2s-3s, and the second predetermined time is 18min-22min;

[0023] The first predetermined pressure is 2KPa-3KPa, and the second predetermined pressure is 15KPa-20KPa;

[0024] The third predetermined time is greater than 48 hours.

[0025] On the other hand, the present application also provides a machine tool, which includes the above-mentioned aluminum alloy casting, or the machine tool includes the aluminum alloy casting obtained by casting using the above-mentioned aluminum alloy casting casting method.

[0026] In the present invention, by adding silicon and magnesium to the aluminum alloy with aluminum and zinc as the main components, the fluidity of the aluminum alloy casting is improved and the strength of the aluminum alloy casting is further enhanced, ensuring that the large-sized aluminum alloy casting is successfully cast. At the same time, the addition of erbium, zirconium and titanium elements can reduce the pores and cracks in the alloy casting process while improving the mechanical properties and corrosion resistance of the aluminum alloy casting, thereby improving the quality of the aluminum alloy casting. In addition, the simultaneous addition of silicon, magnesium, erbium, zirconium and titanium can also improve the plastic deformation ability and processing performance of the alloy, making the aluminum alloy casting easier in the production process. Finally, in order to ensure the quality of the aluminum alloy, it is necessary to strictly control the amount of impurity components in the aluminum alloy. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0028] Figure 1 A flow chart of a casting method for an aluminum alloy casting disclosed in an embodiment of the present invention;

[0029] Figure 2 A schematic diagram of a casting method of an aluminum alloy casting disclosed in an embodiment of the present invention;

[0030] Figure 3 It is a schematic diagram of the aluminum alloy casting disclosed in the embodiment of the present invention, which is hollow due to the short holding time of the aluminum alloy casting;

[0031] Figure 4 It is a schematic diagram of a central area of ​​an aluminum alloy casting that collapses due to excessively high pouring temperature in an aluminum alloy casting disclosed in an embodiment of the present invention;

[0032] Figure 5 It is a schematic diagram of the aluminum alloy casting disclosed in the embodiment of the present invention, in which the riser of the aluminum alloy casting or a part of the casting is not filled and hollows out due to the pouring temperature being too low;

[0033] Figure 6It is a schematic diagram of an aluminum alloy casting disclosed in an embodiment of the present invention in which a riser or a part of the aluminum alloy casting is not filled with aluminum alloy solution due to a slow liquid rising speed.

[0034] The above drawings include the following reference numerals:

[0035] 10. Gate; 20. Runner; 30. Ingate; 40. Riser; 50. Casting. DETAILED DESCRIPTION

[0036] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0037] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0038] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0039] As mentioned in the background technology, there is no heat treatment furnace in the prior art that can accommodate aluminum alloy castings longer than 4 meters, and it is difficult to produce large-sized, high-strength aluminum alloy beams that can be used in machine tools, etc. To this end, the present application provides an aluminum alloy casting that can be exempted from the heat treatment process, and a large-sized, high-strength aluminum alloy casting can be prepared without setting up a large-sized heat treatment furnace.

[0040] Specifically, the components of the aluminum alloy casting in the present application mainly include zinc, aluminum, silicon and magnesium.

[0041] In the present application, the mass percentage of zinc is 9.0%-9.5%. For example, the mass percentage of zinc can be 9.0%, 9.1%, 9.2%, 9.3%, 9.4%, 9.5%, etc.; the mass percentage of aluminum is 80.84%-82.74%. For example, the mass percentage of aluminum can be 80.84%, 80.86%, 81%, 80.5%, 80.2% or 82.74%, etc.; the mass percentage of silicon is 7.5%-8.5%. For example, the mass percentage of silicon can be 7.5%, 7.8%, 7.9%, 8.0%, 8.2%, 8.5%, etc.; the mass percentage of magnesium is 0.4%-0.6%. The mass percentage of magnesium can be 0.4%, 0.5%, 0.6%, etc.

[0042] In the present application, zinc is the main component of the aluminum alloy casting. The strength and hardness of zinc itself are not high, but it has applicable mechanical properties. After forming an alloy with metals such as aluminum, the strength and hardness of the aluminum alloy casting can be improved to a certain extent.

[0043] Aluminum, as the matrix in aluminum alloys, provides a lightweight foundation with a certain lightness. Aluminum has a low density, which helps to maintain the overall lightweight characteristics of the alloy. Aluminum also has good corrosion resistance. A dense aluminum oxide film can be formed on its surface. This film can effectively prevent further corrosion, thereby improving the corrosion resistance of the alloy. In addition, aluminum also has good ductility and plasticity, making aluminum alloys easy to process and shape, such as extrusion, casting and stamping. By adjusting the ratio of aluminum and other alloying elements, the physical and mechanical properties of the alloy can be optimized.

[0044] Silicon is the main component that improves the fluidity of the alloy. And silicon can make the alloy have the best fluidity in the process from eutectic to hypereutectic. However, the crystallized silicon is easy to form hard spots, which makes the cutting performance worse. Therefore, the amount of silicon added in the actual production process will not exceed the eutectic point. In addition, silicon can improve the tensile strength, hardness and cutting performance of aluminum alloy.

[0045] Adding magnesium to the alloy can enhance the strength of the alloy, and magnesium and silicon can form a Mg2Si strengthening phase, and the strength of the alloy can be improved through this aging solidification. If the amount of magnesium added is too high, it will react with other components in the production of the crossbeam, resulting in a significant reduction in the bonding of the crossbeam. Therefore, in this embodiment, during actual production and processing, the mass percentage of magnesium needs to be controlled to 0.4%-0.6% to ensure that the bonding and strength of the crossbeam are within an appropriate range.

[0046] In the aluminum alloy casting of this embodiment, aluminum and zinc are the main components, which can form a structure with relatively light weight, good strength and hardness. In addition, silicon is added to the alloy to improve the fluidity of the alloy. During casting, the alloy liquid can be better filled into the mold, so as to facilitate the casting of beams with a length greater than 4m. At the same time, magnesium is added to the alloy, and magnesium and silicon form a strengthening phase, which further improves the bonding and strength of the aluminum alloy casting. In other words, this embodiment can improve the fluidity and structural strength of the aluminum alloy solution by reasonably configuring the metal materials and their contents in the aluminum alloy casting. In the process of casting the beam, a slender beam with relatively high strength can be produced without equipping a heat treatment boiler to heat treat the aluminum alloy casting, which can reduce the production cost of the machine tool beam.

[0047] In this embodiment, in addition to the above-mentioned metal elements, the aluminum alloy casting also has at least one of the metal elements erbium (Er), zirconium (Zr), and titanium (Ti). In this embodiment, only erbium can be added, or only zirconium can be added, or only titanium can be added, or erbium and zirconium can be added, erbium and titanium can be added, and zirconium and titanium can be added, or erbium, zirconium, and titanium can be added at the same time. In this embodiment, it is preferred to add erbium, zirconium, and titanium at the same time to improve the relevant properties of the aluminum alloy.

[0048] Among them, erbium is a rare earth element that can be used to promote the refinement of the microstructure of aluminum alloys, which is beneficial to improving the mechanical properties of aluminum alloy castings, including strength and toughness; it can also improve the corrosion resistance of aluminum alloy castings. In addition, erbium can not only improve the machinability of the material, making it easier to form and perform other operations, but also control the phase change, affect the phase change process inside the alloy, and then control the final performance of the alloy. Finally, the addition of erbium can reduce the pores and cracks in the casting process of aluminum alloy castings and improve the quality of aluminum alloy castings.

[0049] Specifically, the mass percentage of erbium can be 0.1%, 0.11%, 0.13%, 0.14%, 0.15%, etc. According to the experimental results of the document "The Role of Rare Earth Element Erbium (Er) in Al-Zn-Mg Alloy", when 0.1% erbium is added to Al-Zn-Mg alloy, its mechanical properties increase by 15%. As the amount of erbium added increases, the mechanical properties of the alloy can continue to increase, but when the erbium content exceeds 0.4%, the increase in the hardness and strength of the alloy is no longer obvious. Moreover, erbium will inhibit the recrystallization process of the alloy, increasing the recrystallization temperature of the alloy by about 50°C. In this embodiment, by controlling the mass percentage of erbium between 0.1% and 0.15%, not only the mechanical properties of the aluminum alloy castings can be improved, but also the production cost of the aluminum alloy castings can be further reduced.

[0050] Furthermore, adding zirconium to aluminum alloys is also to improve the performance of the alloys, mainly to improve the strength, heat resistance and processing performance of aluminum alloy castings. Specifically, adding zirconium can promote the refinement of alloy grains. Fine grains can make the alloy material have higher strength and better toughness. It can also improve the thermal stability of the alloy and form stable compounds. The compounds formed in the alloy can be distributed in the matrix as a strengthening phase, further improving the strength and toughness of the alloy; zirconium can also improve the processing performance of the alloy. The presence of zirconium can improve the plastic deformation ability and processing performance of the alloy, making the alloy easier to handle during cold working and hot working. Finally, zirconium can also control phase changes and improve the corrosion resistance of the alloy.

[0051] In this embodiment, the mass percentage of zirconium can be 0.1%, 0.11%, 0.15%, 0.18%, 0.2%, etc. It is worth noting that the amount of zirconium added must be carefully controlled to avoid forming too much hard phase (i.e., some coarse metal compounds), which may reduce the ductility and impact toughness of the alloy. Therefore, in actual processing, the optimal zirconium content must be determined according to the specific alloy formula and required performance.

[0052] Titanium is also added to the alloy. The main purpose of adding titanium to aluminum alloys is to improve the performance of aluminum alloy castings, especially to improve their strength, thermal stability and processing performance. Adding titanium to the alloy can not only solid-dissolve in the matrix to improve the strength of the alloy, but also prevent corrosion by dispersing the layers. Titanium can also improve the processing properties of aluminum alloys, change the plastic deformation ability and processing properties of the alloy, and make the alloy easier to handle during cold processing.

[0053] Specifically, the mass percentage of titanium can be 0.05%, 0.06%, 0.07%, 0.09%, 0.1%, etc. Like the addition of zirconium, the amount of titanium added must also be carefully controlled to avoid the formation of too much hard phase (i.e., some coarse metal compounds), which may also reduce the ductility and impact toughness of the alloy. Therefore, in actual processing, the optimal titanium content must be determined according to the specific alloy formula and required performance. In addition, when the amount of titanium added is too much, huge crystals are easily produced in the alloy, which affects the formability and corrosion resistance of the alloy.

[0054] According to the above description, it can be known that this embodiment improves the fluidity of aluminum alloy castings and further enhances the strength of aluminum alloy castings by adding silicon and magnesium to aluminum alloy with aluminum and zinc as main components, thereby ensuring the successful casting of large-sized aluminum alloy castings. At the same time, the addition of erbium, zirconium and titanium elements can improve the mechanical properties and corrosion resistance of aluminum alloy castings while also reducing pores and cracks in the alloy casting process, thereby improving the quality of aluminum alloy castings; in addition, the simultaneous addition of silicon, magnesium, erbium, zirconium and titanium can also improve the plastic deformation ability and processing performance of the alloy, making aluminum alloy castings easier to produce.

[0055] In this embodiment, the impurity elements contained in the aluminum alloy casting mainly include iron, copper and manganese. The mass percentage of iron is less than or equal to 0.1%; the mass percentage of copper is less than or equal to 0.001%; ​​the mass percentage of manganese is less than or equal to 0.0001%. Specifically, iron has always been considered as a major harmful impurity in cast aluminum alloys. As the iron content increases, needle-shaped and flaky brittle iron phases with high hardness will be formed in the alloy phase structure. Its presence will split the matrix of the aluminum alloy, reduce the mechanical properties of the alloy, especially the toughness, and increase the difficulty of mechanical processing of parts. In this embodiment, the addition of erbium, zirconium and titanium can achieve better phase change control and reduce the influence of impurity iron on the relevant properties of the alloy.

[0056] In aluminum alloys, copper is usually regarded as a possible impurity element. A high content of copper may cause the alloy to form a brittle phase, resulting in brittleness of the material, and may also reduce the plasticity and toughness of the alloy. In addition, the copper content will also affect the casting properties of the alloy. The presence of copper will affect the casting properties such as the fluidity and shrinkage of the alloy liquid, which will in turn affect the quality of the aluminum alloy castings. In this embodiment, aluminum alloy castings are used to manufacture beams with a length greater than 4.0m. When the mass percentage of copper exceeds 0.001%, Al-Cu precipitation is likely to occur, and after die casting, it will shrink and then expand, which will make the aluminum alloy casting unstable. Therefore, in the actual production process, attention should be paid to the content of impurity copper, so that the mass percentage of copper is less than or equal to 0.001%.

[0057] In aluminum alloys, manganese is usually not the main alloying element, but in some cases, manganese can be used as a trace or minor alloying element. The adverse effects of manganese in aluminum alloys may be as follows: (1) Reduced fluidity: The presence of manganese may reduce the fluidity of aluminum alloys, making it difficult for the alloy to fill the mold during the casting process, resulting in a decrease in the quality of aluminum alloy castings; (2) Increased brittleness: Excessive manganese may cause the aluminum alloy to become more brittle, especially the hard phase formed during the cooling process, which will affect the ductility and impact toughness of the alloy; (3) Affected surface quality: The presence of manganese may cause an uneven oxide layer or coating to form on the alloy surface, affecting the appearance of the final product; (4) Affected welding performance: The presence of manganese may affect the welding performance of aluminum alloys, especially the tendency to hot cracking may increase.

[0058] It is worth noting that in some aluminum alloys, an appropriate amount of manganese can be used to refine the grains, thereby improving the strength and toughness of the alloy, while also controlling the effects of other harmful impurities. Therefore, in the actual production process, when designing the formula of aluminum alloy, it is necessary to balance the manganese content according to the specific application to achieve the best comprehensive performance.

[0059] Specifically, impurity elements in aluminum alloys can have a significant impact on their properties. Therefore, in order to ensure the quality of aluminum alloys, it is necessary to strictly control their composition and remove impurities through various metallurgical techniques (such as refining, filtering, etc.).

[0060] In this embodiment, by adding the above-mentioned metal elements and controlling the relevant impurity elements, the tensile strength of the aluminum alloy casting can be increased. Among them, the value of the tensile strength Rm can be 270MPa, 277MPa, 279MPa, 280MPa, 290MPa, etc. In this embodiment, the tensile strength of the alloy material is in the range of 280MPa±10MPa. It can meet the use requirements of the beam of this application. The tensile strength of the beam made of aluminum alloy castings in the laser welder is crucial to ensure the stability and reliability of the equipment. Tensile strength is an indicator of the ability of a material to resist tensile loads without breaking. The tensile strength of the beam on the laser welder has the following main functions: (1) Maintaining structural stability;

[0061] (2) Maintaining precision: Laser welding machines require very high precision. If the tensile strength of the beam is insufficient, it may deform after a long period of work, causing the position and trajectory of the laser head to change, thus affecting the welding precision. (3) Extending the service life of the beam: A beam with high strength can better resist fatigue damage and reduce material fatigue and crack formation caused by repeated loading. (4) Improving safety: A beam with high strength can improve safety and reduce the risk of safety accidents caused by structural failure. (5) Reducing maintenance costs. (6) Adapting to rapid movement: A beam with high tensile strength can better cope with the dynamic load generated by rapid movement and ensure the stability and precision of the laser head at high speed. (7) Reducing vibration: A beam with high tensile strength can effectively reduce the vibration caused by high-speed movement, which is very important for maintaining welding quality and stability. Therefore, according to actual production needs, the minimum tensile strength of the beam in this embodiment is 270MPa, which is guaranteed to be around 280MPa, so as to meet the movement requirements of the laser head and extend the service life and use effect of the beam.

[0062] Further, the elongation δ of the aluminum alloy casting in this embodiment satisfies the relationship: 5%≤δ≤8%. Exemplarily, the value of δ can be 5%, 6.0%, 6.2%, 7.5%, 8.0%, etc. Such a setting ensures the high precision, stability and safety of the laser welding machine during operation. When the elongation of the beam is less than 5%, the beam has a small space for elastic deformation and cannot absorb vibration to a certain extent, resulting in low stability of the structure. If the elongation is greater than 8%, it is easy to cause material fatigue and shorten the service life of the beam; it is also possible that the deformation of the beam is too large, which may cause structural failure and cause safety accidents. When 5%≤δ≤8%, it is beneficial for the beam to maintain a small deformation when bearing load, thereby ensuring the accuracy of welding; it is also beneficial to improve the stability of the beam. When the elongation is greater than or equal to 5%, it indicates that the beam has a certain elastic deformation space, which can absorb vibration to a certain extent, which helps to reduce the vibration and displacement caused by rapid movement, affecting the welding quality and efficiency. The elongation of 8% or less can ensure that the deformation of the beam will not be too large when moving at high speed, thus increasing the service life of the beam and reducing the risk of safety accidents caused by structural failure. In this way, the elongation within this range provides good adaptability of the beam when bearing different loads, which ensures the stability of the beam in normal use and allows a certain elastic deformation to adapt to sudden load changes.

[0063] In order to verify the effect of adding different amounts of metal elements in the aluminum alloy casting of the present invention on the mechanical properties of the aluminum alloy casting, the present invention provides the following specific embodiments and comparative examples:

[0064] Example 1

[0065] An aluminum alloy solution is obtained by smelting in a crucible, and an aluminum alloy solution with a temperature of 660°C-680°C is injected into the mold at a speed of 40mm / s-50mm / s to fill the mold. The mold filled with the aluminum alloy solution is then kept at a pressure of 2KPa-3KPa for 2s-3s to allow the aluminum alloy solution to solidify and form a shell; then, the mold is kept at a pressure of 15KPa-20KPa for 18min-22min to allow the aluminum alloy casting to gradually solidify as a whole; finally, the solidified aluminum alloy casting is kept for more than 48h to form an aluminum alloy casting with good density.

[0066] In this embodiment, the components of the aluminum alloy casting are: the mass percentage of Zn is 9.4%, the mass percentage of Si is 8.04%, the mass percentage of Mg is 0.46%, the mass percentage of Er is 0.11%, the mass percentage of Zr is 0.12%, the mass percentage of Ti is 0.08%, the mass percentage of iron in impurities is less than or equal to 0.1%, the mass percentage of copper is less than or equal to 0.001%, the mass percentage of manganese is less than or equal to 0.0001%, and the mass percentage of aluminum is 82.05%-82.15%. After mechanical testing using heat-free casting, the tensile strength is 283MPa and the elongation is 6%.

[0067] Example 2

[0068] The aluminum alloy casting of Example 2 is substantially the same as that of Example 1, except that, in this embodiment, the components of the aluminum alloy casting are: 9.23% by mass of Zn, 7.94% by mass of Si, 0.43% by mass of Mg, 0.12% by mass of Er, 0.11% by mass of Zr, 0.07% by mass of Ti, less than or equal to 0.1% by mass of iron in impurities, less than or equal to 0.001% by mass of copper, less than or equal to 0.0001% by mass of manganese, and 82.0%-82.1% by mass of aluminum. Mechanical tests after heat-free casting molding show that the tensile strength is 277MPa and the elongation is 6.2%.

[0069] Example 3

[0070] The aluminum alloy casting of Example 3 is substantially the same as that of Example 1, except that, in this embodiment, the components of the aluminum alloy casting are: the mass percentage of Zn is 9.12%, the mass percentage of Si is 8.34%, the mass percentage of Mg is 0.51%, the mass percentage of Er is 0.13%, the mass percentage of Zr is 0.17%, the mass percentage of Ti is 0.06%, the mass percentage of iron in impurities is less than or equal to 0.1%, the mass percentage of copper is less than or equal to 0.001%, the mass percentage of manganese is less than or equal to 0.0001%, and the mass percentage of aluminum is 81.57%-81.67%. Mechanical tests after heat-free casting molding show that the tensile strength is 279MPa and the elongation is 8%.

[0071] Comparative Example 1

[0072] The aluminum alloy casting of Comparative Example 1 is substantially the same as that of Example 1, except that, in this example, the components of the aluminum alloy casting are: 0% by mass of Zn, 7.7% by mass of Si, 0.41% by mass of Mg, 0.13% by mass of Er, 0.11% by mass of Zr, 0.08% by mass of Ti, less than or equal to 0.1% by mass of iron in impurities, less than or equal to 0.001% by mass of copper, less than or equal to 0.0001% by mass of manganese, and 91.57% to 91.67% by mass of aluminum. Mechanical tests after heat-free casting showed that the tensile strength was 185MPa and the elongation was 2.5%.

[0073] Comparative Example 2

[0074] The aluminum alloy casting of Comparative Example 2 is substantially the same as that of Example 1, except that, in this example, the components of the aluminum alloy casting are: 9.12% by mass of Zn, 0% by mass of Si, 0.43% by mass of Mg, 0.12% by mass of Er, 0.11% by mass of Zr, 0.07% by mass of Ti, less than or equal to 0.1% by mass of iron in impurities, less than or equal to 0.001% by mass of copper, less than or equal to 0.0001% by mass of manganese, and 90.05%-90.15% by mass of aluminum. Mechanical tests were performed after heat-free casting, and the tensile strength was 205MPa and the elongation was 3%.

[0075] According to the above embodiments and comparative examples, Table 1 is obtained as follows: the mass percentages of the impurities do not change, which are Fe≤0.1%; Cu≤0.001%; ​​Mn≤0.001%, respectively, and therefore are not listed one by one in the table.

[0076] Table 1:

[0077]

[0078] According to Table 1: By comparing Example 1, Example 2 and Example 3, it can be seen that when the mass percentage of each component in the aluminum alloy casting is within a suitable range, the tensile strength and elongation of the aluminum alloy casting meet the use requirements of the aluminum alloy casting. Among them, when the mass percentage of zinc in the aluminum alloy casting increases, the tensile strength of the aluminum alloy casting gradually decreases. And as the mass percentage of zinc in the aluminum alloy casting increases, the elongation of the aluminum alloy casting tends to increase first and then decrease. When the mass percentage of silicon in the aluminum alloy casting increases first and then decreases, the tensile strength of the aluminum alloy casting tends to increase first and then decrease; but the elongation of the aluminum alloy casting tends to decrease first and then increase.

[0079] By comparing Table 1, Examples 1 to 3 and Comparative Example 1, it can be found that when no zinc is added to the aluminum alloy casting and the mass percentages of other components are within a suitable range, the tensile strength and elongation of the aluminum alloy casting both show a sharp decrease trend.

[0080] By comparing Table 1, Examples 1 to 3 and Comparative Example 2, it can be found that when no silicon is added to the aluminum alloy casting and the mass percentages of other components are within a suitable range, the tensile strength and elongation of the aluminum alloy casting both show a sharp decreasing trend.

[0081] By comparing Table 1, Examples 1 to 3, Comparative Example 1 and Comparative Example 2, it can be found that when no zinc and no silicon are added to the aluminum alloy casting, and the mass percentages of other components are within a suitable range, experiments show that the tensile strength and elongation of the aluminum alloy casting without zinc addition are lower than the tensile strength and elongation of the aluminum alloy casting without silicon addition.

[0082] Specifically, the above situation occurs mainly because zinc is the main component in the aluminum alloy in this embodiment. The role of zinc in aluminum-zinc alloys is mainly to improve the mechanical properties of the alloy, including tensile strength and elongation, through solid solution strengthening and aging precipitation strengthening. After adding a small amount of zinc within an appropriate range, the tensile strength of the aluminum alloy casting is improved. If zinc is not added to the aluminum alloy casting, the hardness of the aluminum alloy casting cannot be guaranteed, and the use requirements of aluminum alloy castings such as beams cannot be met; the reasons for the reduction in tensile strength and elongation of the aluminum alloy may be: (1) Lack of solid solution strengthening: Zinc can dissolve in aluminum at high temperature to form a solid solution. When the alloy casting is cooled, zinc atoms will precipitate from the solid solution to form fine second phase particles. These particles can hinder dislocation movement, thereby improving the strength of the alloy. If there is no zinc, the effect of this solid solution strengthening will be weakened or disappear. (2) Reduction of aging precipitation strengthening: During the aging process, the zinc-based phase precipitated from the supersaturated solid solution can further enhance the hardness and strength of the material. If zinc is missing, then not enough precipitates will form during aging, resulting in a decrease in strength. (3) Changes in grain size: Alloying elements tend to affect grain size, and fine grains generally correspond to higher mechanical properties. The presence of zinc may promote a finer and more uniform grain structure, while the absence of zinc may result in larger grains, which in turn affects the mechanical properties of the material. (4) Plastic deformation ability is affected: The addition of zinc can sometimes improve the plastic deformation ability of the alloy, which may be related to the specific microstructure formed in the alloy. If zinc is missing, the alloy may be more likely to crack when deformed rather than deforming uniformly, thereby reducing the elongation.

[0083] Further, in the aluminum alloy of the present embodiment, with the increase of silicon content, the change trend of tensile strength and elongation is respectively shown as a trend of increasing first and then decreasing and decreasing first and then increasing, which is mainly related to the role of silicon in the alloy and its influence on the microstructure. First, the change trend of tensile strength: at low silicon content, silicon can partially dissolve in the aluminum matrix to form a solid solution, which increases the hardness and strength of the material; in addition, silicon can form compounds or eutectic structures with aluminum and other elements (such as iron), and these reinforcing phases can improve the strength of the material. An appropriate amount of silicon helps to refine the grains of the alloy, and fine grain strengthening is one of the effective means to improve the strength of the material. When the silicon content increases to a certain extent, more and larger brittle phases (such as Al-Si eutectic) may be formed, and the presence of these brittle phases will reduce the overall strength of the material. And too high a silicon content may lead to uneven distribution of reinforcing phases, resulting in inconsistent local performance of the material, thereby affecting the overall tensile strength. In addition, silicon may also be segregated at the grain boundaries to form brittle areas, weakening the bonding force of the grain boundaries.

[0084] Furthermore, in terms of the effect of silicon addition on the elongation of aluminum alloy castings, as the silicon content increases, the brittle phases formed increase, and these brittle phases limit the plastic deformation capacity of the material, resulting in a decrease in elongation. And the presence of brittle phases reduces the effective deformation path of the material during plastic deformation, making the material more susceptible to brittle fracture rather than plastic flow. When the silicon content increases further and reaches a certain range, the brittle phase may become more evenly distributed, which helps to improve the uniform deformation capacity of the material. With the increase in silicon content, the development of certain favorable phase changes or organizational structures may be promoted, and these changes can improve the plastic behavior of the material. Under certain conditions, high silicon content may promote the formation of a new composite material effect, so that the material exhibits better uniformity during plastic deformation, thereby improving the elongation.

[0085] Further, in the present embodiment, when silicon is not added and the other components are kept within a suitable range, the reason why the tensile strength and elongation of the aluminum alloy are reduced may be that silicon can form a reinforcing phase in the aluminum-zinc alloy, such as Al-Si eutectic structure (Al-Si eutectic), and the presence of these phases can improve the tensile strength of the alloy by hindering the movement of dislocations. When silicon is not added, the lack of these reinforcing phases will cause the alloy strength to decrease. Silicon helps to refine the grains, and fine grains can improve the strength of the material. Grain refinement can increase the number of grain boundaries, and grain boundaries can prevent the slip of dislocations, thereby improving the strength of the material. In the absence of silicon, the grains may be larger, resulting in a decrease in tensile strength. The presence of silicon can sometimes improve the plastic deformation ability of the alloy, especially in some alloy systems, the addition of silicon can promote the formation of a microstructure that is conducive to plastic deformation. If the silicon content is insufficient or missing, the material is more likely to crack during the deformation process, rather than uniformly plastically deforming, which leads to a decrease in elongation. Although excessive silicon will lead to the formation of brittle phases, the right amount of silicon can improve the plasticity and strength of the alloy. If silicon is not added at all, the proportion of other brittle phases (such as FeAl3, etc.) in the alloy may increase, and the presence of these brittle phases will reduce the plasticity and toughness of the material. In addition, silicon can also dissolve in the aluminum matrix to form a solid solution, thereby improving the hardness and strength of the alloy through the solid solution strengthening effect. The lack of silicon means that there is less contribution from this solid solution strengthening, so the tensile strength will decrease. The addition of silicon can also affect the microstructure of the alloy, including grain morphology, distribution of second phase particles, etc. These structural changes are crucial to the mechanical properties of the alloy. The absence of silicon may result in a microstructure that is not conducive to the optimization of mechanical properties. Therefore, silicon plays an important role in aluminum alloys, which can improve the strength and plasticity of the alloy. When silicon is not added, the combined effect of the above factors may lead to a decrease in both the tensile strength and elongation of the alloy.

[0086] When zinc is not added to aluminum-zinc alloys, the tensile strength and elongation of the aluminum alloy are usually lower than when silicon is not added. This may be because the aging precipitation strengthening effect and solid solution strengthening effect of zinc are very important for improving the tensile strength of the alloy, and although the strengthening effect of silicon is also significant, it usually does not have the aging strength effect provided by zinc. In addition, the presence of zinc not only helps to improve the strength, but also improves the plasticity and elongation of the alloy by means of grain refinement, etc.; while the lack of silicon mainly affects the strength and plastic deformation ability of the alloy, but usually does not affect the elongation as significantly as zinc. Therefore, on the whole, aluminum alloys without zinc addition usually have lower tensile strength and elongation than aluminum alloys without silicon addition, because zinc provides a more effective strengthening mechanism, especially in aging strengthening.

[0087] like Figures 1 to 6 As shown, the present invention also provides a casting method of an aluminum alloy casting, and the casting method of an aluminum alloy casting is used to prepare the above-mentioned aluminum alloy casting. Specifically, the casting method of the aluminum alloy casting in this embodiment includes the following steps:

[0088] S1: Smelting in a crucible to obtain an aluminum alloy solution, the main components of which include zinc, silicon, magnesium, aluminum, erbium, zirconium and titanium, wherein the mass percentage of zinc is 9.0%-9.5%; the mass percentage of aluminum is 80.84%-82.74%; the mass percentage of silicon is 7.5%-8.5%; the mass percentage of magnesium is 0.4%-0.6%; the mass percentage of erbium is 0.1%-0.15%; the mass percentage of zirconium is 0.1%-0.2%; and the mass percentage of titanium is 0.05%-0.1%;

[0089] When executing step S1, in order to ensure that the tensile strength and elongation of the aluminum alloy casting meet the use requirements of the aluminum alloy casting such as a large-sized beam, the mass percentage of each component of the aluminum alloy casting must be within an appropriate range. After the addition amount of each component is well controlled, the aluminum alloy solution has good fluidity.

[0090] S2: The aluminum alloy solution having a predetermined temperature is injected into the mold at a predetermined speed to fill the mold.

[0091] In this embodiment, the crucible and the mold are integrated, and the aluminum alloy solution obtained after melting is cast using low-pressure casting technology. The aluminum alloy solution in the crucible is injected into the mold through the gate at a liquid rising speed of 40mm / s-50mm / s through the air pressure generated by compressed air, so that the aluminum alloy solution is uniformly filled in all parts of the mold to obtain an ideal temperature field. The predetermined temperature in step S2 is the pouring temperature, which is 660℃-680℃. The pouring temperature is greater than the melting temperature of the aluminum alloy solution, ensuring that the aluminum alloy solution has good fluidity. Figure 4As shown, if the pouring temperature is too high (for example, 700°C), the solidification center of the casting 50 will be "collapsed". Figure 5 As shown, when the pouring temperature is too low (for example, 650° C.), the riser 40 of the casting 50 or a part of the casting 50 may not be filled, and hollowing may occur after the pressure is released. Figure 6 As shown, when the liquid rising speed is too slow (for example, less than 30 mm / s), the riser 40 of the casting 50 or a part of the casting 50 may not be filled, resulting in hollowing after pressure relief.

[0092] S3: maintaining the mold filled with the aluminum alloy solution at a first predetermined pressure for a first predetermined time so that the aluminum alloy solution solidifies to form a crust, then maintaining the mold filled with the aluminum alloy solution at a second predetermined pressure for a second predetermined time so that the aluminum alloy solution in the crust crystallizes, and finally maintaining the aluminum alloy solution in the mold for a third predetermined time so that the aluminum alloy solution forms a solid casting 50.

[0093] The mold filled with aluminum alloy solution is kept at a pressure of 2KPa-3KPa (i.e., crusting pressurization) for 2s-3s to allow the aluminum alloy solution to solidify and form a shell first, making it less likely for the aluminum alloy solution to stick to the mold; then, it is kept at a pressure of 15KPa-20KPa (i.e., crystallization pressurization) for 18min-22min to solidify the aluminum alloy casting as a whole and improve the compactness of the casting 50. In this embodiment, the best time for crystallization pressurization is 20min. Figure 3 As shown, in this embodiment, 5 minutes is taken as an example. If the pressure holding time is too short, the aluminum alloy solution will not be completely solidified after the pressure is released, resulting in hollowing phenomenon.

[0094] By adopting low-pressure casting technology, stable and controllable filling is achieved, and air and slag entrainment defects are reduced; at the same time, a long straight runner 20 and closely spaced inner gates 30 of the same length as the longitudinal dimension are adopted, so that all parts of the crossbeam are uniformly filled with alloy liquid, and an ideal temperature field is obtained. In the subsequent solidification process, the distributed inner gates can compensate for the shrinkage of the casting 50 under the low-pressure casting gas pressure to ensure the internal quality of the casting 50. And after strictly controlling the parameters of the casting method, the casting 50 can be prevented from having defects such as shrinkage and shrinkage holes due to overheating and insufficient compensation pressure.

[0095] The present invention also provides a machine tool, which includes the above-mentioned aluminum alloy casting or the machine tool includes an aluminum alloy casting obtained by casting using a casting method of an aluminum alloy casting. The machine tool may be a laser welder, a laser cutting machine, a CNC machine tool, a gantry milling machine, a bridge crane, etc. The machine tool in this embodiment is a laser welder, which is provided with a crossbeam made of an aluminum alloy casting. As a key component for supporting and moving the laser head, the crossbeam can support the laser head to move at high speed and ensure welding accuracy. The relevant advantages of the aluminum alloy casting and the casting method of the aluminum alloy casting have been described in detail above and will not be repeated here.

[0096] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An aluminum alloy casting, characterized in that: The components of the aluminum alloy casting include: Zinc, aluminum, silicon, and magnesium, wherein the mass percentage of zinc is 9.0%-9.5%; the mass percentage of aluminum is 80.84%-82.74%; the mass percentage of silicon is 7.5%-8.5%; and the mass percentage of magnesium is 0.4%-0.6%.

2. The aluminum alloy casting according to claim 1, characterized in that: The aluminum alloy casting also includes at least one of erbium, zirconium and titanium.

3. The aluminum alloy casting according to claim 2, characterized in that: The mass percentage of erbium is 0.1%-0.15%.

4. The aluminum alloy casting according to claim 2, characterized in that: The mass percentage of zirconium is 0.1%-0.2%.

5. The aluminum alloy casting according to claim 2, characterized in that: The mass percentage of titanium is 0.05%-0.1%.

6. The aluminum alloy casting according to claim 1, characterized in that: The impurities in the aluminum alloy casting include iron, copper and manganese; Wherein, the mass percentage of iron is less than or equal to 0.1%; the mass percentage of copper is less than or equal to 0.001%; The mass percentage of manganese is less than or equal to 0.0001%.

7. The aluminum alloy casting according to any one of claims 1 to 5, characterized in that: The tensile strength Rm of the aluminum alloy casting satisfies the relationship: Rm≥270MPa.

8. The aluminum alloy casting according to any one of claims 1 to 5, characterized in that: The elongation δ of the aluminum alloy casting satisfies the relationship: 5%≤δ≤8%.

9. A method for casting an aluminum alloy casting, characterized in that: The aluminum alloy casting according to any one of claims 1 to 8, wherein the casting method of the aluminum alloy casting comprises the following steps: S1: Smelting in a crucible to obtain an aluminum alloy solution, wherein the main components of the aluminum alloy solution include zinc, silicon, magnesium, aluminum, erbium, zirconium and titanium, wherein the mass percentage of zinc is 9.0%-9.5%; the mass percentage of aluminum is 80.84%-82.74%; the mass percentage of silicon is 7.5%-8.5%; the mass percentage of magnesium is 0.4%-0.6%; the mass percentage of erbium is 0.1%-0.15%; the mass percentage of zirconium is 0.1%-0.2%; the mass percentage of titanium is 0.05%-0.1%; S2: injecting the aluminum alloy solution having a predetermined temperature at a predetermined speed to fill the mold; S3: maintaining the mold filled with the aluminum alloy solution at a first predetermined pressure for a first predetermined time so that the aluminum alloy solution solidifies to form a crust, then maintaining the mold filled with the aluminum alloy solution at a second predetermined pressure for a second predetermined time so that the aluminum alloy solution in the crust crystallizes, and finally maintaining the aluminum alloy solution in the mold for a third predetermined time so that the aluminum alloy solution forms a solid casting.

10. The casting method of aluminum alloy casting according to claim 9, characterized in that: The predetermined temperature in step S2 is 660°C-680°C.

11. The casting method of aluminum alloy casting according to claim 9, characterized in that: The predetermined speed in step S2 is 40 mm / s-50 mm / s.

12. The casting method of aluminum alloy casting according to claim 9, characterized in that: The first predetermined time in step S3 is 2s-3s, and the second predetermined time is 18min-22min; The first predetermined pressure is 2KPa-3KPa, and the second predetermined pressure is 15KPa-20KPa; The third predetermined time is greater than 48 hours.

13. A machine tool, characterized in that: The machine tool comprises the aluminum alloy casting according to any one of claims 1 to 8, or the machine tool comprises the aluminum alloy casting obtained by casting using the casting method of the aluminum alloy casting according to any one of claims 9 to 12.

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