Aluminum alloy for preparing integral axle box body of train built-in bogie and preparation method of aluminum alloy

Abstract

The invention discloses an aluminum alloy for preparing an integral axle box body of a built-in bogie of a train and a preparation method of the aluminum alloy, and belongs to the technical field of metallurgy. The aluminum alloy comprises the following components in percentage by weight: 5%-8% of Zn, 0.5%-3% of Mg, 0.5%-3% of Cu, 0.05%-0.5% of Zr, 0.01%-0.5% of Ti, 0.05%-0.5% of Y, 0.05%-1.5% of Si, 0.05%-1.5% of Sr, 0.1%-3% of Sm and the balance of Al and inevitable impurities. The axle box body with excellent mechanical performance is prepared by limiting the chemical components of the aluminum alloy and the ratio of all the components, optimizing different ratios of the elements and exploring the synergistic effect of the elements.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgy, and in particular relates to an aluminum alloy for preparing an integral axle box body of a built-in bogie of a train and a preparation method thereof. Background Art

[0002] With the gradual increase in the speed of high-speed trains and the important demand for energy conservation and environmental protection, the further lightweighting of the integrated axle box of high-speed trains has become a basic element in the design and manufacture of high-speed trains, and it is also an inevitable trend. The axle boxes of currently operating high-speed trains are mainly made of ductile iron, resulting in a high overall quality of the axle boxes. As a lightweight structural material, aluminum alloy 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.

[0003] At present, my country has the independent production capacity of aluminum alloy materials used in high-speed trains, but a large amount of tracking test data and failure analysis data and feedback data shared by vehicle factories and car body manufacturers show that the performance of high-speed trains is not stable enough during service, especially in terms of tensile strength and elongation after fracture. The main reason is that there are still some problems in the chemical composition, extrusion processing technology, process and post-heat treatment technology and process of domestic aluminum alloy materials, which leads to the weakening of material performance. Therefore, it is urgent to develop an aluminum alloy material for high-speed trains with excellent mechanical properties. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention provides an aluminum alloy for preparing an integral axle box body of a built-in train bogie and a preparation method thereof, which can effectively solve the problem of insufficient mechanical properties of existing aluminum alloy materials.

[0005] To achieve the above purpose, the technical solution adopted by the present invention to solve the technical problem is:

[0006] The object of the present invention is to provide an aluminum alloy for preparing an integral axle box body of a train built-in bogie, comprising the following components in weight percentage:

[0007] Zn 5-8%, Mg 0.5-3%, Cu 0.5-3%, Zr 0.05-0.5%, Ti 0.01-0.5%, Y 0.05-0.5%, Si 0.05-1.5%, Sr 0.05-1.5%, Sm 0.1-3%, and the balance is Al and inevitable impurities.

[0008] Further, the following components are included in weight percentage:

[0009] Zn 5.8-8%, Mg 1.0-3%, Cu 1.5-3%, Zr 0.05-0.3%, Ti 0.01-0.3%, Y 0.05-0.4%, Si 0.5-1.5%, Sr 0.5-1.5%, Sm 0.1-2.5%, and the balance is Al and inevitable impurities.

[0010] Further, the following components are included in weight percentage:

[0011] Zn 5.8-7.6%, Mg 1.5-2.0%, Cu 2.0-3%, Zr 0.1-0.3%, Ti 0.04-0.2%, Y 0.05-0.35%, Si 0.5-1.0%, Sr 0.5-1.0%, Sm 0.1-2%, and the balance is Al and inevitable impurities.

[0012] Furthermore, it is characterized in that the mass ratio of Sm to Y (Sm / Y) is 1-5.

[0013] Furthermore, the mass ratio of Sm to Y (Sm / Y) is 1 to 1.5.

[0014] The present invention introduces Sr element into the aluminum alloy formula in order to improve the demoulding effect of the material and offset the adverse effects of inevitable impurities; the addition of Si and Mg elements in the formula is used to improve the strength of the aluminum alloy, but if the addition amount of Si and Mg elements is too high, the elongation after fracture will be reduced, and if the addition amount of Si and Mg elements is too low, the strength will be reduced. Therefore, by adding strontium element into the formula, the tensile strength of the aluminum alloy can be effectively improved, and the adverse effects of Si and Mg elements can be improved.

[0015] The formula also contains Cu and Zn elements, which can also make up for the gaps between atoms of other metal elements, reduce internal loose defects, and thus achieve a comprehensive improvement in mechanical properties. In addition, the present invention also adds Sm elements, which can effectively refine the organization and improve the elongation after fracture. At the same time, the amount ratio of Sm / Y is further limited to within 1 to 5, thereby greatly increasing the amount of strength increase without damaging various properties such as strength and bake hardenability. The addition of trace Y forms Al8Cu4Y phase in the alloy, which is beneficial to the alloy performance. In addition, the Y element also forms Al3Y particles, which accelerate the aging process of the alloy while pinning dislocations.

[0016] Another object of the present invention is to provide a method for preparing the aluminum alloy for preparing the integrated axle box body of a built-in bogie for a train, comprising the following steps:

[0017] (1) pure Al is heated and melted, then the melt temperature is raised to 680°C-700°C, and Al-Cu master alloy is added;

[0018] (2) Continue to raise the melt temperature to 720-740°C, add Al-Zr, Al-Ti, Al-Y, and Al-Si master alloys; lower the melt temperature to 690-710°C, and add pure Zn and pure Mg;

[0019] (3) The melt is heated to 720-730° C., Al-Sr and Al-Sm master alloys are added, stirred for 2-5 minutes, and then allowed to stand for 5-10 minutes; when the temperature drops to 710-720° C., the aluminum alloy is cast.

[0020] Furthermore, the temperature in step (1) is 700°C.

[0021] Furthermore, the temperatures in step (2) are 740° C. and 700° C. respectively.

[0022] Furthermore, the temperature in step (3) is 720°C.

[0023] Another object of the present invention is to provide an integrated axle box body for a train built-in bogie, the preparation method of which is as follows:

[0024] (1) casting the aluminum alloy to form a casting billet and removing the outer skin, heating to 380-450° C. and keeping the temperature for 8-14 hours, then continuing to heat to 450-490° C. and keeping the temperature for 20-26 hours, and cooling with water at room temperature;

[0025] (2) heating the treated alloy billet to 380-450°C for 2-6 hours, and then hot extruding, with the preheating temperature of the extrusion barrel being 380-450°C and the extrusion ratio being ≥10;

[0026] (3) heating the alloy extrusion billet obtained in step (2) to 380-450° C. and keeping the temperature for 2-6 hours;

[0027] (4) The alloy blank obtained in step (3) is subjected to superplastic die forging, wherein the die preheating temperature is 380-450°C, the die forging temperature is 380-450°C, and the die forging rate is 10×10 -5 ~10×10 -2 mm / s, to obtain the aluminum alloy axle box forging blank with pre-breaking treatment;

[0028] (5) The aluminum alloy axle box forging blank obtained in step (4) is subjected to superplastic die forging final forging, the die preheating temperature is 380-450°C, the die forging temperature is 380-450°C, and the die forging rate is 10×10 -5 ~10×10 -2 mm / s, to obtain the aluminum alloy axle box forging blank after final forging;

[0029] (6) The aluminum alloy axle box forging blank obtained in step (5) is subjected to rough machining, heat treatment and fine machining in sequence to obtain the integral axle box of the built-in bogie of the train.

[0030] Further, the heat treatment process is as follows:

[0031] Heat the rough-machined aluminum alloy shaft box to 450-500℃ and keep it for 2-6h, then cool it with water at room temperature; then heat it to 110-140℃ and keep it for 18-26h, then cool it with air.

[0032] Beneficial effects of the present invention:

[0033] The present invention limits the chemical composition of the aluminum alloy and the ratio of each component, optimizes the different ratios between elements and explores the synergy between elements to obtain an aluminum alloy material with excellent mechanical properties. Therefore, even if the ratio of aluminum product waste in the raw material is increased or the raw material is all aluminum product waste, the above-mentioned aluminum alloy can be easily produced. DETAILED DESCRIPTION

[0034] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0035] Example 1

[0036] An aluminum alloy for preparing an integral axle box body of a train built-in bogie comprises the following components in percentage by weight:

[0037] Zn 5.8%, Mg 1.5%, Cu 2.5%, Zr 0.1%, Ti 0.05%, Y 0.2%, Si 0.5%, Sr 0.8%, Sm 0.3%, and the balance is Al and inevitable impurities.

[0038] The preparation method is as follows:

[0039] (1) Pure Al is heated and melted, then the melt temperature is raised to 700°C and Al-Cu master alloy is added;

[0040] (2) Continue to raise the melt temperature to 720°C and add Al-Zr, Al-Ti, Al-Y, and Al-Si master alloys; lower the melt temperature to 700°C and add pure Zn and pure Mg;

[0041] (3) The melt is heated to 720° C., Al-Sr and Al-Sm master alloys are added, stirred for 2-5 minutes, and then allowed to stand for 5-10 minutes; when the temperature drops to 710° C., the aluminum alloy is cast.

[0042] The specific process of the integrated axle box body of the train built-in bogie made of the above aluminum alloy is as follows:

[0043] (1) Casting alloy ingot: The aluminum alloy ingot is prepared by the above method.

[0044] (2) Homogenization treatment: remove the outer skin of the aluminum alloy ingot obtained in step (1), heat to 380°C and keep it for 12 hours, then continue to heat to 490°C and keep it for 20 hours, and cool it with water at room temperature.

[0045] (3) Hot extrusion: The alloy billet obtained in step (2) is heated to 450°C and kept at this temperature for 4 hours, and then hot extruded. The preheating temperature of the extrusion barrel is 380°C, and the extrusion ratio is ≥10.

[0046] (4) Preheating: Heat the alloy extrusion billet obtained in step (3) to 380°C and keep it warm for 2-6 hours.

[0047] (5) Superplastic die forging: The alloy blank obtained in step (4) is placed in a pre-forging die for superplastic die forging to obtain an aluminum alloy axle box forging blank. The die preheating temperature is 450°C, the die forging temperature is 450°C, and the die forging rate is 10×10 - 5 mm / s.

[0048] (6) Superplastic die forging final forging: The alloy billet obtained in step (5) is placed in a final forging die for superplastic die forging to obtain an aluminum alloy axle box forging billet. The die preheating temperature is 450°C, the die forging temperature is 380°C, and the die forging rate is 10×10 - 5 mm / s.

[0049] (7) Rough machining: The aluminum alloy axle box forging blank obtained in step (6) is rough machined according to the axle box rough machining drawing.

[0050] (8) Heat treatment: The rough-machined aluminum alloy shaft box obtained in step (7) is heated to 500° C. and kept at this temperature for 3 h, and then water-cooled at room temperature; then heated to 140° C. and kept at this temperature for 26 h, and then air-cooled.

[0051] (9) Finishing: The aluminum alloy axle box body obtained in step (8) is finish-machined according to the axle box body finishing drawing.

[0052] Example 2

[0053] An aluminum alloy for preparing an integral axle box body of a train built-in bogie comprises the following components in percentage by weight:

[0054] Zn 5%, Mg 3%, Cu 0.5%, Zr 0.05%, Ti 0.01%, Y 0.5%, Si 0.05%, Sr 1.5%, Sm 1.5%, and the balance is Al and inevitable impurities.

[0055] The preparation method is as follows:

[0056] (1) Pure Al is heated and melted, then the melt temperature is raised to 680°C and Al-Cu master alloy is added;

[0057] (2) Continue to raise the melt temperature to 720°C and add Al-Zr, Al-Ti, Al-Y, and Al-Si master alloys; lower the melt temperature to 710°C and add pure Zn and pure Mg;

[0058] (3) The melt is heated to 730° C., Al-Sr and Al-Sm master alloys are added, stirred for 2-5 minutes, and then allowed to stand for 5-10 minutes; when the temperature drops to 720° C., the aluminum alloy is cast.

[0059] The integrated axle box body of the train built-in bogie made of the above aluminum alloy has the following specific process:

[0060] (1) Casting alloy ingot: The aluminum alloy ingot is prepared by the above method.

[0061] (2) Homogenization treatment: remove the outer skin of the aluminum alloy ingot obtained in step (1), heat to 380°C and keep it for 14 hours, then continue to heat to 450°C and keep it for 26 hours, and cool it with water at room temperature.

[0062] (3) Hot extrusion: The alloy billet obtained in step (2) is heated to 450°C and kept at this temperature for 2 hours, and then hot extruded. The preheating temperature of the extrusion barrel is 400°C, and the extrusion ratio is ≥10.

[0063] (4) Preheating: Heat the alloy extrusion billet obtained in step (3) to 380°C and keep it at this temperature for 5 hours.

[0064] (5) Superplastic die forging: The alloy blank obtained in step (4) is placed in a pre-forging die for superplastic die forging to obtain an aluminum alloy axle box forging blank. The die preheating temperature is 450°C, the die forging temperature is 400°C, and the die forging rate is 10×10 - 2 mm / s.

[0065] (6) Superplastic die forging final forging: The alloy billet obtained in step (5) is placed in a final forging die for superplastic die forging to obtain an aluminum alloy axle box forging billet. The die preheating temperature is 450°C, the die forging temperature is 380°C, and the die forging rate is 10×10 - 2 mm / s.

[0066] (7) Rough machining: The aluminum alloy axle box forging blank obtained in step (6) is rough machined according to the axle box rough machining drawing.

[0067] (8) Heat treatment: heat the rough-machined aluminum alloy shaft box obtained in step (7) to 450°C and keep it for 6 hours, and then cool it with water at room temperature; then heat it to 110°C and keep it for 20 hours, and then cool it in air.

[0068] (9) Finishing: The aluminum alloy axle box body obtained in step (8) is finish-machined according to the axle box body finishing drawing.

[0069] Example 3

[0070] An aluminum alloy for preparing an integral axle box body of a train built-in bogie comprises the following components in percentage by weight:

[0071] Zn 8%, Mg 0.5%, Cu 3%, Zr 0.5%, Ti 0.5%, Y 0.5%, Si 1.5%, Sr 0.5%, Sm 3%, and the balance is Al and inevitable impurities.

[0072] The preparation method is as follows:

[0073] (1) Pure Al is heated and melted, then the melt temperature is raised to 700°C and Al-Cu master alloy is added;

[0074] (2) Continue to raise the melt temperature to 740°C and add Al-Zr, Al-Ti, Al-Y, and Al-Si master alloys; lower the melt temperature to 690°C and add pure Zn and pure Mg;

[0075] (3) The melt is heated to 720° C., Al-Sr and Al-Sm master alloys are added, stirred for 2-5 minutes, and then allowed to stand for 5-10 minutes; when the temperature drops to 720° C., the aluminum alloy is cast.

[0076] The integrated axle box body of the train built-in bogie made of the above aluminum alloy has the following specific process:

[0077] (1) Casting alloy ingot: The aluminum alloy ingot is prepared by the above method.

[0078] (2) Homogenization treatment: remove the outer skin of the aluminum alloy ingot obtained in step (1), heat to 420°C and keep it for 10 hours, then continue to heat to 450°C and keep it for 20 hours, and cool it with water at room temperature.

[0079] (3) Hot extrusion: The alloy billet obtained in step (2) is heated to 380°C and kept at this temperature for 5 hours, and then hot extruded. The preheating temperature of the extrusion barrel is 400°C, and the extrusion ratio is ≥10.

[0080] (4) Preheating: Heat the alloy extrusion billet obtained in step (3) to 380°C and keep it at this temperature for 6 hours.

[0081] (5) Superplastic die forging: The alloy blank obtained in step (4) is placed in a pre-forging die for superplastic die forging to obtain an aluminum alloy axle box forging blank. The die preheating temperature is 400°C, the die forging temperature is 420°C, and the die forging rate is 10×10 - 3 mm / s.

[0082] (6) Superplastic die forging final forging: The alloy billet obtained in step (5) is placed in a final forging die for superplastic die forging to obtain an aluminum alloy axle box forging billet. The die preheating temperature is 420°C, the die forging temperature is 450°C, and the die forging rate is 10×10 - 3 mm / s.

[0083] (7) Rough machining: The aluminum alloy axle box forging blank obtained in step (6) is rough machined according to the axle box rough machining drawing.

[0084] (8) Heat treatment: heat the rough-machined aluminum alloy shaft box obtained in step (7) to 450°C and keep it for 5 hours, and then cool it with water at room temperature; then heat it to 130°C and keep it for 20 hours, and then cool it in air.

[0085] (9) Finishing: The aluminum alloy axle box body obtained in step (8) is finish-machined according to the axle box body finishing drawing.

[0086] Comparative Example 1

[0087] Compared with Example 1, the ratio of Sm / Y is changed to be less than 1, and the rest of the process is the same as that of Example 1. The specific ratio is as follows:

[0088] An aluminum alloy comprising the following components in weight percentage:

[0089] Zn 5.8%, Mg 1.5%, Cu 2.5%, Zr 0.1%, Ti 0.05%, Y 0.2%, Si 0.5%, Sr 0.8%, Sm 0.4%, and the balance is Al and inevitable impurities.

[0090] Comparative Example 2

[0091] Compared with Example 1, the ratio of Sm / Y is changed to be greater than 5, and the rest of the process is the same as that of Example 1. The specific ratio is as follows:

[0092] Zn 5.8%, Mg 1.5%, Cu 2.5%, Zr 0.1%, Ti 0.05%, Y 0.2%, Si 0.5%, Sr 0.8%, Sm 2.0%, and the balance is Al and inevitable impurities.

[0093] Comparative Example 3

[0094] Compared with Example 1, La is used to replace Sr used in the solution, and the amount of Si and Mg is increased. The rest of the process is the same as that of Example 1. The specific ratio is as follows:

[0095] Zn 5.8%, Mg 3.2%, Cu 2.5%, Zr 0.1%, Ti 0.05%, Y 0.2%, Si 2.4%, La 0.8%, Sm 2.0%, and the balance is Al and inevitable impurities.

[0096] Comparative Example 4

[0097] Compared with Example 1, Sm used in the V replacement scheme is adopted, and the rest of the process is the same as that of Example 1, and the specific proportions are as follows:

[0098] An aluminum alloy comprising the following components in weight percentage:

[0099] Zn 5.8%, Mg 1.5%, Cu 2.5%, Zr 0.1%, Ti 0.05%, Y 0.2%, Si 0.5%, Sr 0.8%, V 0.4%, and the balance is Al and inevitable impurities.

[0100] Comparative Example 5

[0101] According to the national standard AlSi 10 The aluminum alloy was prepared with a MnMg grade ratio, and the rest of the process was the same as in Example 1.

[0102] Performance Testing

[0103] The tensile strength, yield strength and elongation after fracture of the axle boxes prepared in Examples 1 to 3 and Comparative Examples 1 to 4 were tested by conventional methods well known in the art. The results are shown in Table 1.

[0104] Table 1 Axle box performance

[0105] Tensile strength(MPa) Yield strength(MPa) Elongation after break (%) Example 1 706 653 14.6 Example 2 698 661 13.1 Example 3 693 648 13.7 Comparative Example 1 416 376 9.6 Comparative Example 2 462 415 10.3 Comparative Example 3 537 468 11.3 Comparative Example 4 493 421 14.2 Comparative Example 5 548 459 5.4

[0106] According to the test results in Table 1, the overall performance of the axle box prepared by the technical solution of the present application in terms of tensile strength, yield strength and elongation after fracture is significantly better than that of comparative examples 1 to 5, among which the technical effect of embodiment 1 is the best.

[0107] For Comparative Examples 1 to 5, Comparative Examples 1 and 2 changed the ratio of Sm / Y in the alloy formula, which greatly affected the overall performance of the axle box. Comparative Examples 3 and 4 both changed the alloy formula composition. After the formula was changed, a certain performance of the axle box was optimized, such as tensile strength / yield strength, or elongation after fracture, but this is only the advantage of a single performance. From the overall effect, the performance of the axle box prepared by the changed comparative examples is still not comparable to that prepared by the embodiment of the present application.

[0108] It can be seen that the present invention obtains an aluminum alloy material with high tensile strength, high elongation after fracture and high yield strength by selecting appropriate metal elements, optimizing different ratios between elements and exploring the synergistic effect between elements.

[0109] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. An aluminum alloy for preparing an integral axle box body of a train built-in bogie, characterized in that: The composition includes the following weight percentages: Zn 5-8%, Mg 0.5-3%, Cu 0.5-3%, Zr 0.05-0.5%, Ti 0.01-0.5%, Y 0.05-0.5%, Si 0.05-1.5%, Sr 0.05-1.5%, Sm 0.1-3%, and the balance is Al and inevitable impurities.

2. The aluminum alloy for preparing an integral axle box body of a train built-in bogie according to claim 1, characterized in that: The composition includes the following weight percentages: Zn 5.8-8%, Mg 1.0-3%, Cu 1.5-3%, Zr 0.05-0.3%, Ti 0.01-0.3%, Y 0.05-0.4%, Si 0.5-1.5%, Sr 0.5-1.5%, Sm 0.1-2.5%, and the balance is Al and inevitable impurities.

3. The aluminum alloy for preparing an integral axle box body of a train built-in bogie according to claim 1, characterized in that: The composition includes the following weight percentages: Zn 5.8-7.6%, Mg 1.5-2.0%, Cu 2.0-3%, Zr 0.1-0.3%, Ti 0.04-0.2%, Y 0.05-0.35%, Si 0.5-1.0%, Sr 0.5-1.0%, Sm 0.1-2%, and the balance is Al and inevitable impurities.

4. The aluminum alloy for preparing an integral axle box body of a train built-in bogie according to any one of claims 1 to 3, characterized in that: The mass ratio of Sm to Y (Sm / Y) is 1-5.

5. The aluminum alloy for preparing an integral axle box body of a train built-in bogie according to claim 4, characterized in that: The mass ratio of Sm to Y, Sm / Y, is 1 to 1.

5.

6. A method for preparing the aluminum alloy for preparing an integral axle box of a train built-in bogie according to any one of claims 1 to 5, characterized in that: The following steps are involved: (1) pure Al is heated and melted, then the melt temperature is raised to 680°C-700°C, and Al-Cu master alloy is added; (2) Continue to raise the melt temperature to 720-740°C, add Al-Zr, Al-Ti, Al-Y, and Al-Si master alloys; lower the melt temperature to 690-710°C, and add pure Zn and pure Mg; (3) The melt is heated to 720-730° C., Al-Sr and Al-Sm master alloys are added, stirred for 2-5 minutes, and then allowed to stand for 5-10 minutes; when the temperature drops to 710-720° C., the aluminum alloy is cast.

7. The method according to claim 6, characterized in that The temperature in step (1) is 700°C.

8. The method according to claim 6, characterized in that The temperatures in step (2) are 740°C and 700°C respectively.

9. The method according to claim 6, characterized in that The temperature in step (3) is 720°C.

10. An integrated axle box body for a train built-in bogie, characterized in that: The preparation method is as follows: (1) Casting the aluminum alloy according to any one of claims 1 to 5 to form a casting billet and removing the outer skin, heating to 380-450° C. and keeping the temperature for 8-14 hours, then continuing to heat to 450-490° C. and keeping the temperature for 20-26 hours, and cooling with water at room temperature; (2) heating the treated alloy billet to 380-450°C for 2-6 hours, and then hot extruding, with the preheating temperature of the extrusion barrel being 380-450°C and the extrusion ratio being ≥10; (3) heating the alloy extrusion billet obtained in step (2) to 380-450° C. and keeping the temperature for 2-6 hours; (4) The alloy blank obtained in step (3) is subjected to superplastic die forging, wherein the die preheating temperature is 380-450°C, the die forging temperature is 380-450°C, and the die forging rate is 10×10 -5 ~10×10 -2 mm / s, to obtain the aluminum alloy axle box forging blank with pre-breaking treatment; (5) The aluminum alloy axle box forging blank obtained in step (4) is subjected to superplastic die forging final forging, the die preheating temperature is 380-450°C, the die forging temperature is 380-450°C, and the die forging rate is 10×10 -5 ~10×10 -2 mm / s, to obtain the aluminum alloy axle box forging blank after final forging; (6) The aluminum alloy axle box forging blank obtained in step (5) is subjected to rough machining, heat treatment and fine machining in sequence to obtain the integral axle box of the train built-in bogie.