Aluminum alloy for preparing split type axle box body of external bogie of train and preparation method of aluminum alloy

Abstract

The invention discloses an aluminum alloy for preparing a split axle box body of an external bogie of a train and a preparation method of the aluminum alloy, and belongs to the technical field of alloys for high-speed trains. The aluminum alloy comprises Zn, Mg, Si, Cu, Ca, Zr, Ti, Mn, Y, Al and other elements. When the aluminum alloy is prepared, one-time homogenization treatment, one-time thermoplastic deformation processing treatment and two-time superplastic die forging treatment are carried out; wherein the homogenization treatment can eliminate residual stress and defects, such as dendritic crystals, in the cast ingot, and improve the overall structure performance of the alloy, so that the solid solubility of a coarse compound phase in the alloy is improved; the thermoplastic deformation processing treatment and the twice superplastic die forging treatment can further eliminate new segregation and stress concentration caused by deformation, so that the microstructure of the alloy is more uniform.

Description

Technical Field

[0001] The present invention belongs to the technical field of alloys for high-speed trains, and in particular relates to an aluminum alloy for preparing a split axle box body of an external bogie of a train and a preparation method thereof. Background Art

[0002] With the gradual increase in the operating speed of high-speed trains and the important demand for energy conservation and environmental protection, the further lightweighting of high-speed trains has become a basic element in the design and manufacture of high-speed trains, and is also an inevitable trend.

[0003] In recent years, with the increasing requirements for high speed and lightweight of high-speed trains, the performance requirements for external axle boxes are also increasing. The high-speed requirements of steel external axle boxes have been seriously affected by their high density. Meeting the high-standard mechanical performance requirements of external axle boxes while achieving weight reduction is a major reform and structural adjustment faced by the development of high-speed trains. The implementation of speed-up and safe development technologies requires in-depth structural optimization and component lightweighting of external axle boxes. The axle boxes of external bogies of currently operating high-speed trains are mainly made of ductile iron materials, resulting in a high overall mass of the axle boxes. Aluminum alloy, as a lightweight structural material, has the advantages of low density, high strength, good electrical and thermal conductivity, good corrosion resistance, easy forming and processing, and has been widely used in the manufacturing field of high-speed trains. There are reports on the use of aluminum alloys to prepare high-speed train axle boxes to reduce the mass of the axle boxes and achieve lightweighting, but its performance is difficult to meet the requirements of high-speed train axle boxes. Summary of the invention

[0004] In view of the above-mentioned prior art, the present invention provides an aluminum alloy for preparing a split axle box body of an external bogie of a train and a preparation method thereof, so as to solve the technical problems of heavy weight and low strength of the existing axle box body materials.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is to provide an aluminum alloy for preparing a split axle box body of an external bogie of a train, comprising the following components in percentage by mass:

[0006] Zn 3-5%, Mg 3-5%, Si 0.5-2%, Cu 2-4%, Ca 0.01-0.05%, Zr 0.5-0.7%, Ti 0.05-0.2%, Mn 0.05-0.2%, Y 0.01-0.03%, and the balance is Al and unavoidable impurities.

[0007] Based on the above technical solution, the present invention can also be improved as follows.

[0008] Furthermore, the aluminum alloy used to prepare the split axle box of the train external bogie includes the following components in percentage by mass:

[0009] Zn 4%, Mg 5%, Si 1%, Cu 3%, Ca 0.03%, Zr 0.6%, Ti 0.1%, Mn 0.15%, Y 0.02%, and the balance is Al and inevitable impurities.

[0010] The present invention also discloses a method for preparing the aluminum alloy for preparing a split axle box of an external bogie of a train, comprising the following steps:

[0011] S1: preparing a cast Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy by mixing raw materials according to the mass percentage of each element in the alloy and melting and pouring the raw materials;

[0012] S2: homogenizing the cast Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy;

[0013] S3: performing hot plastic deformation processing on the homogenized Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy;

[0014] S4: performing superplastic die forging on the Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy that has been subjected to hot plastic deformation processing;

[0015] S5: heat treating the Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy after superplastic die forging to obtain.

[0016] Further, the raw materials include aluminum ingots, zinc ingots, magnesium ingots, silicon powder, copper ingots, calcium ingots, Al-5Zr alloy, Al-Ti alloy, electrolytic manganese flakes and Al-10Y alloy.

[0017] Further, the cast Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy is prepared by the following steps:

[0018] S11: heating an aluminum ingot twice the mass of the calcium ingot until it is melted, then adjusting the melt temperature to 800-850°C, adding the calcium ingot into the melt, and smelting it for 10-20 minutes at a heat preservation temperature, then removing the surface slag, and then pouring it into an Al-Ca master alloy;

[0019] S12: Heat half of the remaining aluminum ingot until it is melted, then adjust the melt temperature to 720-750°C, add the copper ingot, keep warm and smelt for 30-60 minutes, stir the melt for 3-5 minutes, and adjust the melt temperature to 700-720°C, then add the zinc ingot and the magnesium ingot to the melt, keep warm and smelt for 20-30 minutes, and then adjust the melt temperature to 730-750°C, then add the Al-5Zr alloy, the Al-Ti alloy and the Al-10Y alloy, keep warm and smelt for 30-60 minutes, then adjust the melt temperature to 690-710°C, then add the electrolytic manganese sheet, keep warm and smelt for 20-30 minutes, stir the melt for 5-10 minutes, then let it stand for 10-20 minutes, and then cast it into an Al-Zn-Mg-Cu-Zr-Ti-Mn-Y master alloy;

[0020] S13: Heat the remaining aluminum ingots until they are melted, adjust the melt temperature to 800-850°C, then add the Al-Zn-Mg-Cu-Zr-Ti-Mn-Y master alloy to the melt, keep warm and smelt for 60-120 minutes, then adjust the temperature of the melt to 780-820°C, then add silicon powder, stir for 5-10 minutes, and then keep warm and smelt for 30-60 minutes, then add the Al-Ca master alloy, continue to smelt for 30-60 minutes, then cool to 650-680°C, let stand for 30-45 minutes, and then pour to obtain.

[0021] Furthermore, the first homogenization treatment method in S2 is: heating the cast Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy from room temperature to 300-320°C at a heating rate of 10°C / min, and keeping it warm for 5-10 hours; then heating it to 400-420°C at a heating rate of 5°C / min, and keeping it warm for 10-15 hours; then heating it to 500-520°C at a heating rate of 5°C / min, and keeping it warm for 10-15 hours; then cooling it to room temperature with the furnace.

[0022] Furthermore, the hot plastic deformation processing method in S3 is: the Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy after homogenization is heated to 370-450°C at a heating rate of 5°C / min, kept warm for 3-5h, and then hot extruded with an extrusion ratio of 9-30:1.

[0023] Furthermore, the superplastic forging treatment in S4 is as follows: the Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy that has been subjected to thermoplastic deformation is heated to 380-470°C at a heating rate of 5°C / min, kept at this temperature for 2-12 hours, and then heated at 380-470°C for 10 -5 ~10 -1The pre-forged billet is forged at a die forging rate of 10 mm / s. -5 ~10 - 1 The pre-forged billet is subjected to secondary die forging at a die forging rate of mm / s to obtain the final forging billet.

[0024] Furthermore, the heat treatment in S5 is as follows: heating the Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy after superplastic forging to 440-500°C at a heating rate of 5°C / min, keeping it at that temperature for 2-10 hours, and water cooling it at room temperature; then heating it to 110-150°C at a heating rate of 3°C / min, keeping it at that temperature for 9-26 hours, and then air cooling it to room temperature.

[0025] The beneficial effects of the present invention are:

[0026] 1. The aluminum alloy of the present invention contains elements such as Zn, Mg, Si, Cu, Ca, Zr, Ti, Mn, and Y. When casting the cast Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy, the present invention first melts Zn, Mg, Cu, Zr, Ti, Mn, Y, etc. together with aluminum and casts them into Al-Zn-Mg-Cu-Zr-Ti-Mn-Y master alloy, which is beneficial to the MgZn2, Al3Zr, Al 20 The formation of second phases such as Ti2Y, Al8Cu4Y, and Al3(Zr,Ti), and the subsequent addition of Al-Zn-Mg-Cu-Zr-Ti-Mn-Y intermediate alloy during the smelting process can introduce strengthening phases into the final alloy, thereby improving the toughness and strength of the aluminum alloy. In addition, aluminum and calcium are first smelted together to form an Al-Ca intermediate alloy, and then the Al-Ca intermediate alloy is added in the subsequent smelting process to introduce calcium into the final alloy; the present invention can ensure the uniform distribution of calcium in the aluminum alloy by preparing the Al-Ca intermediate alloy, and can effectively avoid the component segregation phenomenon caused by directly adding calcium ingots, and the Al-Ca intermediate alloy can provide a heterogeneous nucleation core for the aluminum alloy melt, promote the nucleation process in the melt, thereby refining the grain structure, and then improving the strength and toughness of the aluminum alloy, so that the comprehensive mechanical properties of the aluminum alloy can be improved; in addition, in the overall smelting process, the calcium in the Al-Ca intermediate alloy will form stable intermetallic compounds such as CaAl, CaAl2, and CaAl4 with aluminum, and the calcium itself will also form a dispersed strengthening phase. These intermetallic compounds and strengthening phases can effectively hinder the dislocation movement in the alloy, thereby improving the strength of the alloy; introducing calcium into the alloy can also change the phase composition of other alloy elements in the aluminum alloy. For example, calcium can reduce the tendency of generating Al2Mg3Zn3 phase intergranular particles, thereby improving the plasticity of the aluminum alloy and making it easier to process and shape.

[0027] 2. The aluminum alloy elements in the present invention include silicon, and silicon is added in the form of silicon powder during the smelting process. The aluminum alloy obtained through the preparation process of the present invention contains eutectic silicon phase structures such as α-Al / Si eutectic, which can not only significantly improve the casting performance of the alloy and make it easier to process and shape, but also these eutectic silicon phases exist in the form of rods, which can improve the metallographic structure of the aluminum alloy, so that the obtained aluminum alloy has excellent mechanical and fatigue resistance.

[0028] 3. When preparing the aluminum alloy, the present invention performs one homogenization treatment, one hot plastic deformation processing treatment and two superplastic die forging treatments; wherein, the homogenization treatment can eliminate the residual stress and defects in the ingot, such as dendrites, and improve the overall organizational properties of the alloy to increase the solid solubility of the coarse compound phase in the alloy; the hot plastic deformation processing treatment and two superplastic die forging treatments can further eliminate the new segregation and stress concentration caused by deformation, making the microstructure of the alloy more uniform. DETAILED DESCRIPTION

[0029] The specific implementation modes of the present invention are described in detail below with reference to the embodiments.

[0030] Example 1

[0031] An aluminum alloy for preparing a split axle box body of an external bogie of a train, comprising the following components in percentage by mass:

[0032] Zn 4%, Mg 5%, Si 1%, Cu 3%, Ca 0.03%, Zr 0.6%, Ti 0.1%, Mn 0.15%, Y 0.02%, and the balance is Al and inevitable impurities.

[0033] The aluminum alloy used to prepare the split axle box body of the train external bogie in this embodiment is prepared by the following steps:

[0034] S1: preparing raw materials according to the mass percentage of each element in the alloy, the raw materials including aluminum ingot, zinc ingot, magnesium ingot, silicon powder, copper ingot, calcium ingot, Al-5Zr alloy, Al-Ti alloy, electrolytic manganese sheet and Al-10Y alloy; smelting and pouring the raw materials according to the following steps to prepare a cast Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy;

[0035] S11: heating an aluminum ingot twice the mass of the calcium ingot until it is melted, then adjusting the melt temperature to 830°C, adding the calcium ingot into the melt, keeping the temperature to melt for 15 minutes, then removing the surface scum, and then pouring into Al-Ca master alloy;

[0036] S12: Heat half of the remaining aluminum ingot until it is melted, then adjust the melt temperature to 740°C, add the copper ingot, keep warm and smelt for 45 minutes, stir the melt for 4 minutes, and adjust the melt temperature to 710°C, then add the zinc ingot and the magnesium ingot to the melt, keep warm and smelt for 25 minutes, and then adjust the melt temperature to 740°C, then add the Al-5Zr alloy, the Al-Ti alloy and the Al-10Y alloy, keep warm and smelt for 45 minutes, and then adjust the melt temperature to 700°C, then add the electrolytic manganese sheet, keep warm and smelt for 25 minutes, stir the melt for 8 minutes, then let it stand for 15 minutes, and then cast it into an Al-Zn-Mg-Cu-Zr-Ti-Mn-Y intermediate alloy;

[0037] S13: heating the remaining aluminum ingot to melt, adjusting the melt temperature to 820°C, then adding Al-Zn-Mg-Cu-Zr-Ti-Mn-Y master alloy to the melt, keeping the temperature for 90 minutes, then adjusting the temperature of the melt to 800°C, then adding silicon powder, stirring for 8 minutes, and then keeping the temperature for 45 minutes, then adding Al-Ca master alloy, continuing to melt for 45 minutes, then cooling to 660°C, standing for 45 minutes, and then pouring to obtain a cast Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy;

[0038] S2: The cast Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy is heated from room temperature to 310°C at a heating rate of 10°C / min and kept at this temperature for 8 hours; then the temperature is heated to 410°C at a heating rate of 5°C / min and kept at this temperature for 12 hours; then the temperature is heated to 510°C at a heating rate of 5°C / min and kept at this temperature for 12 hours; then the cast Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy is cooled to room temperature with the furnace to complete the homogenization treatment of the cast Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy;

[0039] S3: The Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy after homogenization is heated to 400°C at a heating rate of 5°C / min, kept at this temperature for 4 hours, and then hot extruded with an extrusion ratio of 25:1 to complete the hot plastic deformation processing;

[0040] S4: The Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy that had been subjected to thermoplastic deformation was heated to 420°C at a heating rate of 5°C / min and kept at this temperature for 10 h; -3 mm / s to obtain a pre-forged billet; then forging at 420°C for 10 -3 The pre-forged billet is subjected to secondary die forging at a die forging rate of mm / s to obtain a final forging billet, completing the superplastic die forging process;

[0041] S5: Heat the Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy after superplastic forging to 470°C at a heating rate of 5°C / min, keep it at that temperature for 5 hours, and water-cool it at room temperature; then heat it to 120°C at a heating rate of 3°C / min, keep it at that temperature for 24 hours, and then air-cool it to room temperature.

[0042] Example 2

[0043] An aluminum alloy for preparing a split axle box body of an external bogie of a train, comprising the following components in percentage by mass:

[0044] Zn 3%, Mg 5%, Si 0.5%, Cu 4%, Ca 0.01%, Zr 0.7%, Ti 0.05%, Mn 0.2%, Y 0.01%, and the balance is Al and inevitable impurities.

[0045] The aluminum alloy used to prepare the split axle box body of the train external bogie in this embodiment is prepared by the following steps:

[0046] S1: preparing raw materials according to the mass percentage of each element in the alloy, the raw materials including aluminum ingot, zinc ingot, magnesium ingot, silicon powder, copper ingot, calcium ingot, Al-5Zr alloy, Al-Ti alloy, electrolytic manganese sheet and Al-10Y alloy; smelting and pouring the raw materials according to the following steps to prepare a cast Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy;

[0047] S11: heating an aluminum ingot twice the mass of the calcium ingot until it is melted, then adjusting the melt temperature to 800°C, adding the calcium ingot into the melt, and smelting the melt for 20 minutes at a heat preservation temperature, then removing the surface slag, and then casting into an Al-Ca master alloy;

[0048] S12: Heat half of the remaining aluminum ingot until it is melted, then adjust the melt temperature to 720°C, add the copper ingot, keep warm and smelt for 60 minutes, stir the melt for 5 minutes, and adjust the melt temperature to 700°C, then add the zinc ingot and the magnesium ingot to the melt, keep warm and smelt for 30 minutes, and then adjust the melt temperature to 730°C, then add the Al-5Zr alloy, the Al-Ti alloy and the Al-10Y alloy, keep warm and smelt for 60 minutes, then adjust the melt temperature to 690°C, then add the electrolytic manganese sheet, keep warm and smelt for 30 minutes, stir the melt for 10 minutes, then let it stand for 10 minutes, and then cast it into an Al-Zn-Mg-Cu-Zr-Ti-Mn-Y intermediate alloy;

[0049] S13: heating the remaining aluminum ingot to melt, adjusting the melt temperature to 800°C, then adding Al-Zn-Mg-Cu-Zr-Ti-Mn-Y master alloy to the melt, keeping the temperature for smelting for 120 minutes, then adjusting the temperature of the melt to 780°C, then adding silicon powder, stirring for 10 minutes, and then keeping the temperature for smelting for 60 minutes, then adding Al-Ca master alloy, continuing to smelt for 60 minutes, then cooling to 650°C, standing for 45 minutes, and then pouring to obtain a cast Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy;

[0050] S2: The cast Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy is heated from room temperature to 300°C at a heating rate of 10°C / min and kept at this temperature for 10 hours; then the cast Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy is heated to 400°C at a heating rate of 5°C / min and kept at this temperature for 15 hours; then the cast Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy is heated to 500°C at a heating rate of 5°C / min and kept at this temperature for 15 hours; then the cast Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy is cooled to room temperature with the furnace to complete the homogenization treatment of the cast Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy;

[0051] S3: The Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy after homogenization is heated to 370°C at a heating rate of 5°C / min, kept at this temperature for 5 hours, and then hot extruded with an extrusion ratio of 30:1 to complete the hot plastic deformation processing;

[0052] S4: The Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy that had been subjected to thermoplastic deformation was heated to 380°C at a heating rate of 5°C / min and kept at this temperature for 12 h; -5 mm / s to obtain a pre-forged billet; then forging was performed at 380°C for 10 -5 The pre-forged billet is subjected to secondary die forging at a die forging rate of mm / s to obtain a final forging billet, completing the superplastic die forging process;

[0053] S5: Heat the Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy after superplastic forging to 440°C at a heating rate of 5°C / min, keep it at that temperature for 10 hours, and water-cool it at room temperature; then heat it to 110°C at a heating rate of 3°C / min, keep it at that temperature for 26 hours, and then air-cool it to room temperature.

[0054] Example 3

[0055] An aluminum alloy for preparing a split axle box body of an external bogie of a train, comprising the following components in percentage by mass:

[0056] Zn 5%, Mg 3%, Si 2%, Cu 2%, Ca 0.05%, Zr 0.5%, Ti 0.2%, Mn 0.05%, Y 0.03%, and the balance is Al and inevitable impurities.

[0057] The aluminum alloy used to prepare the split axle box body of the train external bogie in this embodiment is prepared by the following steps:

[0058] S1: preparing raw materials according to the mass percentage of each element in the alloy, the raw materials including aluminum ingot, zinc ingot, magnesium ingot, silicon powder, copper ingot, calcium ingot, Al-5Zr alloy, Al-Ti alloy, electrolytic manganese sheet and Al-10Y alloy; smelting and pouring the raw materials according to the following steps to prepare a cast Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy;

[0059] S11: heating an aluminum ingot twice the mass of the calcium ingot until it is melted, then adjusting the melt temperature to 850°C, adding the calcium ingot into the melt, keeping the temperature to melt for 10 minutes, removing the surface scum, and then casting into Al-Ca master alloy;

[0060] S12: Heat half of the remaining aluminum ingot until it is melted, then adjust the melt temperature to 750°C, add the copper ingot, keep warm and smelt for 30 minutes, stir the melt for 3 minutes, and adjust the melt temperature to 720°C, then add the zinc ingot and the magnesium ingot to the melt, keep warm and smelt for 20 minutes, and then adjust the melt temperature to 750°C, then add the Al-5Zr alloy, the Al-Ti alloy and the Al-10Y alloy, keep warm and smelt for 30 minutes, and then adjust the melt temperature to 710°C, then add the electrolytic manganese sheet, keep warm and smelt for 20 minutes, stir the melt for 5 minutes, then let it stand for 20 minutes, and then cast it into an Al-Zn-Mg-Cu-Zr-Ti-Mn-Y intermediate alloy;

[0061] S13: heating the remaining aluminum ingot to melt, adjusting the melt temperature to 850°C, then adding Al-Zn-Mg-Cu-Zr-Ti-Mn-Y master alloy to the melt, keeping the temperature for 60 minutes, then adjusting the temperature of the melt to 820°C, then adding silicon powder, stirring for 5 minutes, and then keeping the temperature for 30 minutes, then adding Al-Ca master alloy, continuing to melt for 30 minutes, then cooling to 680°C, standing for 30 minutes, and then pouring to obtain a cast Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy;

[0062] S2: heating the cast Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy from room temperature to 320°C at a heating rate of 10°C / min, and keeping it at that temperature for 5 hours; then heating it to 420°C at a heating rate of 5°C / min, and keeping it at that temperature for 10 hours; then heating it to 520°C at a heating rate of 5°C / min, and keeping it at that temperature for 10 hours; then cooling it to room temperature with the furnace, and completing the homogenization treatment of the cast Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy;

[0063] S3: The Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy after homogenization is heated to 450°C at a heating rate of 5°C / min, kept at this temperature for 3 hours, and then hot extruded with an extrusion ratio of 9:1 to complete the hot plastic deformation processing;

[0064] S4: The Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy that had been subjected to thermoplastic deformation was heated to 470°C at a heating rate of 5°C / min and kept at this temperature for 2 h. -1 mm / s die forging rate to obtain a pre-forged billet; then at 470 ° C for 10 -1 The pre-forged billet is subjected to secondary die forging at a die forging rate of mm / s to obtain a final forging billet, completing the superplastic die forging process;

[0065] S5: Heat the Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy after superplastic forging to 500°C at a heating rate of 5°C / min, keep it at that temperature for 2 hours, and water-cool it at room temperature; then heat it to 150°C at a heating rate of 3°C / min, keep it at that temperature for 9 hours, and then air-cool it to room temperature.

[0066] Comparative Example 1

[0067] An aluminum alloy for preparing a split axle box body of an external bogie of a train, comprising the following components in percentage by mass:

[0068] Zn 4%, Mg 5%, Si 1%, Cu 3%, Zr 0.6%, Ti 0.1%, Mn 0.15%, Y 0.02%, and the balance is Al and inevitable impurities.

[0069] The aluminum alloy used to prepare the split axle box of the train external bogie in this comparative example is prepared by the following steps:

[0070] S1: preparing raw materials according to the mass percentage of each element in the alloy, the raw materials including aluminum ingot, zinc ingot, magnesium ingot, silicon powder, copper ingot, Al-5Zr alloy, Al-Ti alloy, electrolytic manganese sheet and Al-10Y alloy; smelting and pouring the raw materials according to the following steps to prepare a cast Al-Zn-Mg-Si-Cu-Zr-Ti-Mn-Y alloy;

[0071] S11: Heat half of the aluminum ingot until it is melted, then adjust the melt temperature to 740°C, add the copper ingot, keep warm and smelt for 45 minutes, stir the melt for 4 minutes, and adjust the melt temperature to 710°C, then add the zinc ingot and the magnesium ingot to the melt, keep warm and smelt for 25 minutes, and then adjust the melt temperature to 740°C, then add the Al-5Zr alloy, the Al-Ti alloy and the Al-10Y alloy, keep warm and smelt for 45 minutes, and then adjust the melt temperature to 700°C, then add the electrolytic manganese sheet, keep warm and smelt for 25 minutes, stir the melt for 8 minutes, then let it stand for 15 minutes, and then cast it into an Al-Zn-Mg-Cu-Zr-Ti-Mn-Y master alloy;

[0072] S12: heating the remaining aluminum ingot to melt, adjusting the melt temperature to 820°C, then adding the Al-Zn-Mg-Cu-Zr-Ti-Mn-Y master alloy to the melt, keeping the temperature for 90 minutes, then adjusting the temperature of the melt to 800°C, then adding silicon powder, stirring for 8 minutes, and then keeping the temperature for 45 minutes, then cooling to 660°C, standing for 45 minutes, and then pouring to obtain a cast Al-Zn-Mg-Si-Cu-Zr-Ti-Mn-Y alloy;

[0073] S2: The cast Al-Zn-Mg-Si-Cu-Zr-Ti-Mn-Y alloy is heated from room temperature to 310°C at a heating rate of 10°C / min and kept at this temperature for 8 hours; then the temperature is heated to 410°C at a heating rate of 5°C / min and kept at this temperature for 12 hours; then the temperature is heated to 510°C at a heating rate of 5°C / min and kept at this temperature for 12 hours; then the cast Al-Zn-Mg-Si-Cu-Zr-Ti-Mn-Y alloy is cooled to room temperature in the furnace to complete the homogenization treatment of the cast Al-Zn-Mg-Si-Cu-Zr-Ti-Mn-Y alloy;

[0074] S3: The Al-Zn-Mg-Si-Cu-Zr-Ti-Mn-Y alloy after homogenization is heated to 400°C at a heating rate of 5°C / min, kept at this temperature for 4 hours, and then hot extruded with an extrusion ratio of 25:1 to complete the hot plastic deformation processing;

[0075] S4: The Al-Zn-Mg-Si-Cu-Zr-Ti-Mn-Y alloy that had been subjected to thermoplastic deformation was heated to 420°C at a heating rate of 5°C / min and kept at this temperature for 10 h;-3 mm / s to obtain a pre-forged billet; then forging at 420°C for 10 -3 The pre-forged billet is subjected to secondary die forging at a die forging rate of mm / s to obtain a final forging billet, completing the superplastic die forging process;

[0076] S5: Heat the Al-Zn-Mg-Si-Cu-Zr-Ti-Mn-Y alloy after superplastic forging to 470°C at a heating rate of 5°C / min, keep it at that temperature for 5 hours, and water-cool it at room temperature; then heat it to 120°C at a heating rate of 3°C / min, keep it at that temperature for 24 hours, and then air-cool it to room temperature.

[0077] Comparative Example 2

[0078] An aluminum alloy for preparing a split axle box body of an external bogie of a train, comprising the following components in percentage by mass:

[0079] Zn 4%, Mg 5%, Cu 3%, Ca 0.03%, Zr 0.6%, Ti 0.1%, Mn 0.15%, Y 0.02%, and the balance is Al and inevitable impurities.

[0080] The aluminum alloy used to prepare the split axle box of the train external bogie in this comparative example is prepared by the following steps:

[0081] S1: preparing raw materials according to the mass percentage of each element in the alloy, the raw materials including aluminum ingot, zinc ingot, magnesium ingot, copper ingot, calcium ingot, Al-5Zr alloy, Al-Ti alloy, electrolytic manganese sheet and Al-10Y alloy; smelting and pouring the raw materials according to the following steps to prepare a cast Al-Zn-Mg-Cu-Ca-Zr-Ti-Mn-Y alloy;

[0082] S11: heating an aluminum ingot twice the mass of the calcium ingot until it is melted, then adjusting the melt temperature to 830°C, adding the calcium ingot into the melt, keeping the temperature to melt for 15 minutes, then removing the surface scum, and then pouring into Al-Ca master alloy;

[0083] S12: Heat half of the remaining aluminum ingot until it is melted, then adjust the melt temperature to 740°C, add the copper ingot, keep warm and smelt for 45 minutes, stir the melt for 4 minutes, and adjust the melt temperature to 710°C, then add the zinc ingot and the magnesium ingot to the melt, keep warm and smelt for 25 minutes, and then adjust the melt temperature to 740°C, then add the Al-5Zr alloy, the Al-Ti alloy and the Al-10Y alloy, keep warm and smelt for 45 minutes, and then adjust the melt temperature to 700°C, then add the electrolytic manganese sheet, keep warm and smelt for 25 minutes, stir the melt for 8 minutes, then let it stand for 15 minutes, and then cast it into an Al-Zn-Mg-Cu-Zr-Ti-Mn-Y intermediate alloy;

[0084] S13: heating the remaining aluminum ingots to melt, adjusting the melt temperature to 820°C, then adding the Al-Zn-Mg-Cu-Zr-Ti-Mn-Y master alloy to the melt, keeping the temperature to smelt for 90 minutes, then adjusting the temperature of the melt to 800°C, then adding the Al-Ca master alloy, continuing to smelt for 45 minutes, then cooling to 660°C, standing for 45 minutes, and then pouring to obtain a cast Al-Zn-Mg-Cu-Ca-Zr-Ti-Mn-Y alloy;

[0085] S2: The cast Al-Zn-Mg-Cu-Ca-Zr-Ti-Mn-Y alloy is heated from room temperature to 310°C at a heating rate of 10°C / min and kept at this temperature for 8 hours; then the temperature is heated to 410°C at a heating rate of 5°C / min and kept at this temperature for 12 hours; then the temperature is heated to 510°C at a heating rate of 5°C / min and kept at this temperature for 12 hours; then the cast Al-Zn-Mg-Cu-Ca-Zr-Ti-Mn-Y alloy is cooled to room temperature in the furnace to complete the homogenization treatment of the cast Al-Zn-Mg-Cu-Ca-Zr-Ti-Mn-Y alloy;

[0086] S3: The Al-Zn-Mg-Cu-Ca-Zr-Ti-Mn-Y alloy after homogenization is heated to 400°C at a heating rate of 5°C / min, kept at this temperature for 4 hours, and then hot extruded with an extrusion ratio of 25:1 to complete the hot plastic deformation processing;

[0087] S4: The Al-Zn-Mg-Cu-Ca-Zr-Ti-Mn-Y alloy that had been subjected to thermoplastic deformation was heated to 420°C at a heating rate of 5°C / min and kept at this temperature for 10 h; -3 mm / s to obtain a pre-forged billet; then forging at 420°C for 10 -3 The pre-forged billet is subjected to secondary die forging at a die forging rate of mm / s to obtain a final forging billet, completing the superplastic die forging process;

[0088] S5: Heat the Al-Zn-Mg-Cu-Ca-Zr-Ti-Mn-Y alloy after superplastic forging to 470°C at a heating rate of 5°C / min, keep it at that temperature for 5 hours, and water-cool it at room temperature; then heat it to 120°C at a heating rate of 3°C / min, keep it at that temperature for 24 hours, and then air-cool it to room temperature.

[0089] Comparative Example 3

[0090] An aluminum alloy for preparing a split axle box body of an external bogie of a train, comprising the following components in percentage by mass:

[0091] Zn 4%, Mg 5%, Si 1%, Cu 3%, Ca 0.03%, Zr 0.6%, Ti 0.1%, Mn 0.15%, Y 0.02%, and the balance is Al and inevitable impurities.

[0092] The aluminum alloy used to prepare the split axle box body of the train external bogie in this embodiment is prepared by the following steps:

[0093] S1: preparing raw materials according to the mass percentage of each element in the alloy, the raw materials including aluminum ingot, zinc ingot, magnesium ingot, silicon powder, copper ingot, calcium ingot, Al-5Zr alloy, Al-Ti alloy, electrolytic manganese sheet and Al-10Y alloy; smelting and pouring the raw materials according to the following steps to prepare a cast Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy;

[0094] S11: heating an aluminum ingot twice the mass of the calcium ingot until it is melted, then adjusting the melt temperature to 830°C, adding the calcium ingot into the melt, keeping the temperature to melt for 15 minutes, then removing the surface scum, and then pouring into Al-Ca master alloy;

[0095] S12: Heat half of the remaining aluminum ingot until it is melted, then adjust the melt temperature to 740°C, add the copper ingot, keep warm and smelt for 45 minutes, stir the melt for 4 minutes, and adjust the melt temperature to 710°C, then add the zinc ingot and the magnesium ingot to the melt, keep warm and smelt for 25 minutes, and then adjust the melt temperature to 740°C, then add the Al-5Zr alloy, the Al-Ti alloy and the Al-10Y alloy, keep warm and smelt for 45 minutes, and then adjust the melt temperature to 700°C, then add the electrolytic manganese sheet, keep warm and smelt for 25 minutes, stir the melt for 8 minutes, then let it stand for 15 minutes, and then cast it into an Al-Zn-Mg-Cu-Zr-Ti-Mn-Y intermediate alloy;

[0096] S13: heating the remaining aluminum ingot to melt, adjusting the melt temperature to 820°C, then adding Al-Zn-Mg-Cu-Zr-Ti-Mn-Y master alloy to the melt, keeping the temperature for 90 minutes, then adjusting the temperature of the melt to 800°C, then adding silicon powder, stirring for 8 minutes, and then keeping the temperature for 45 minutes, then adding Al-Ca master alloy, continuing to melt for 45 minutes, then cooling to 660°C, standing for 45 minutes, and then pouring to obtain a cast Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy;

[0097] S2: The cast Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy is heated from room temperature to 310°C at a heating rate of 10°C / min and kept at this temperature for 8 hours; then the temperature is heated to 410°C at a heating rate of 5°C / min and kept at this temperature for 12 hours; then the temperature is heated to 510°C at a heating rate of 5°C / min and kept at this temperature for 12 hours; then the cast Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy is cooled to room temperature with the furnace to complete the homogenization treatment of the cast Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy;

[0098] S3: The Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy after homogenization is heated to 400°C at a heating rate of 5°C / min, kept at this temperature for 4 hours, and then hot extruded with an extrusion ratio of 25:1 to complete the hot plastic deformation processing;

[0099] S4: The Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy after thermoplastic deformation is heated to 470°C at a heating rate of 5°C / min, kept at this temperature for 5 hours, and water-cooled at room temperature; then the temperature is heated to 120°C at a heating rate of 3°C / min, kept at this temperature for 24 hours, and then air-cooled to room temperature.

[0100] Results Analysis

[0101] The aluminum alloys for preparing the split axle box of the train external bogie prepared in the above embodiments and comparative examples were subjected to performance tests, and the test items included tensile strength, yield strength, fatigue resistance, density, etc., wherein the fatigue test parameters were: stress ratio of 0.1, vibration frequency of 60-70 Hz, and number of cycles of 1×10 7 The test results are shown in Table 1.

[0102] Table 1 Comprehensive properties of aluminum alloy

[0103]

[0104] Although the specific implementation of the present invention is described in detail in conjunction with the embodiments, it should not be understood as limiting the scope of protection of this patent. Within the scope described in the claims, various modifications and variations that can be made by those skilled in the art without creative work still fall within the scope of protection of this patent.

Claims

1. An aluminum alloy for preparing a split axle box body of an external bogie of a train, characterized in that: The following components are included in mass percentage: Zn 3-5%, Mg 3-5%, Si 0.5-2%, Cu 2-4%, Ca 0.01-0.05%, Zr 0.5-0.7%, Ti 0.05-0.2%, Mn 0.05-0.2%, Y 0.01-0.03%, and the balance is Al and unavoidable impurities.

2. The aluminum alloy for preparing a split axle box body of an external bogie of a train according to claim 1, characterized in that: The following components are included in mass percentage: Zn 4%, Mg 5%, Si 1%, Cu 3%, Ca 0.03%, Zr 0.6%, Ti 0.1%, Mn 0.15%, Y 0.02%, and the balance is Al and inevitable impurities.

3. The method for preparing the aluminum alloy for preparing the split axle box of the train external bogie according to claim 1 or 2, characterized in that: The following steps are involved: S1: preparing a cast Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy by mixing raw materials according to the mass percentage of each element in the alloy and melting and pouring the raw materials; S2: homogenizing the cast Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy; S3: performing hot plastic deformation processing on the homogenized Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy; S4: performing superplastic die forging on the Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy that has been subjected to hot plastic deformation processing; S5: heat treating the Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy after superplastic die forging to obtain.

4. The preparation method according to claim 3, characterized in that: The raw materials include aluminum ingots, zinc ingots, magnesium ingots, silicon powder, copper ingots, calcium ingots, Al-5Zr alloy, Al-Ti alloy, electrolytic manganese sheets and Al-10Y alloy.

5. The preparation method according to claim 4, characterized in that: The cast Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy is prepared by the following steps: S11: heating an aluminum ingot twice the mass of the calcium ingot until it is melted, then adjusting the melt temperature to 800-850°C, adding the calcium ingot into the melt, and smelting it for 10-20 minutes at a heat preservation temperature, then removing the surface slag, and then pouring it into an Al-Ca master alloy; S12: Heat half of the remaining aluminum ingot until it is melted, then adjust the melt temperature to 720-750°C, add the copper ingot, keep warm and smelt for 30-60 minutes, stir the melt for 3-5 minutes, and adjust the melt temperature to 700-720°C, then add the zinc ingot and the magnesium ingot to the melt, keep warm and smelt for 20-30 minutes, and then adjust the melt temperature to 730-750°C, then add the Al-5Zr alloy, the Al-Ti alloy and the Al-10Y alloy, keep warm and smelt for 30-60 minutes, then adjust the melt temperature to 690-710°C, then add the electrolytic manganese sheet, keep warm and smelt for 20-30 minutes, stir the melt for 5-10 minutes, then let it stand for 10-20 minutes, and then cast it into an Al-Zn-Mg-Cu-Zr-Ti-Mn-Y master alloy; S13: Heat the remaining aluminum ingots until they are melted, adjust the melt temperature to 800-850°C, then add the Al-Zn-Mg-Cu-Zr-Ti-Mn-Y master alloy to the melt, keep warm and smelt for 60-120 minutes, then adjust the temperature of the melt to 780-820°C, then add silicon powder, stir for 5-10 minutes, and then keep warm and smelt for 30-60 minutes, then add the Al-Ca master alloy, continue to smelt for 30-60 minutes, then cool to 650-680°C, let stand for 30-45 minutes, and then pour to obtain.

6. The preparation method according to claim 3, characterized in that: The homogenization treatment method in S2 is: heat the cast Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy from room temperature to 300-320°C at a heating rate of 10°C / min, and keep it warm for 5-10 hours; then heat it to 400-420°C at a heating rate of 5°C / min, and keep it warm for 10-15 hours; then heat it to 500-520°C at a heating rate of 5°C / min, and keep it warm for 10-15 hours; then cool it to room temperature with the furnace.

7. The preparation method according to claim 3, characterized in that: The hot plastic deformation processing method in S3 is: the Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy after homogenization is heated to 370-450°C at a heating rate of 5°C / min, kept warm for 3-5h, and then hot extruded with an extrusion ratio of 9-30:

1.

8. The preparation method according to claim 3, characterized in that: The superplastic forging process in S4 is as follows: the Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy that has been subjected to thermoplastic deformation is heated to 380-470°C at a heating rate of 5°C / min, kept at this temperature for 2-12 hours, and then heated at 380-470°C for 10 -5 ~10 -1 The pre-forged billet is forged at a die forging rate of 10 mm / s. -5 ~10 -1 The pre-forged billet is subjected to secondary die forging at a die forging rate of mm / s to obtain the final forging billet.

9. The preparation method according to claim 3, characterized in that: The heat treatment in S5 is as follows: the Al-Zn-Mg-Si-Cu-Ca-Zr-Ti-Mn-Y alloy after superplastic forging is heated to 440-500°C at a heating rate of 5°C / min, kept at this temperature for 2-10 hours, and water-cooled at room temperature; then the temperature is heated to 110-150°C at a heating rate of 3°C / min, kept at this temperature for 9-26 hours, and then air-cooled to room temperature.

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