Aluminum alloy for preparing traction rod of train built-in bogie and preparation method of aluminum alloy

Abstract

The invention discloses an aluminum alloy for preparing a train built-in bogie traction rod and a preparation method of the aluminum alloy, and belongs to the technical field of metal material preparation. The preparation method of the aluminum alloy comprises the following steps: (1) respectively heating and melting intermediate alloys such as pure Al, Al-Zn and Al-Mg, and then mixing and stirring to obtain an alloy melt; (2) introducing mixed inert gas and a refining agent from the bottom of the alloy melt, then continuously introducing the inert gas, and removing surface scum; (3) degassing the alloy melt treated in the step (2), and sintering in a pulsed magnetic field environment; and (4) after sintering is finished, cooling is conducted, plasma treatment is adopted in the cooling process, then casting is conducted after continuous cooling, and the aluminum alloy casting blank is obtained. Through the constructed preparation method, the defects in the alloy can be effectively reduced, the diffusion effect of atoms in the alloy is promoted, the phenomenon of uneven distribution of structures in the alloy is improved, and the service performance of the alloy is improved.

Description

Technical Field

[0001] This invention belongs to the field of metal material preparation technology, specifically relating to an aluminum alloy for preparing traction rods for train bogies and its preparation method. Background Technology

[0002] With the increasing speed of high-speed trains and the growing demand for energy conservation and environmental protection, further weight reduction of traction rods has become a fundamental element and an inevitable trend in the design and manufacturing of high-speed trains. Currently, the aluminum alloy traction rods of the internal bogies of operating high-speed trains are mainly made of ductile iron, resulting in a relatively high overall weight. Aluminum alloy, as a lightweight structural material, also possesses advantages such as low density, high strength, good electrical and thermal conductivity, good corrosion resistance, and ease of forming and processing, and has been widely used in the manufacturing of high-speed trains. However, the performance of currently produced traction rods is insufficient to meet the high requirements of high-speed trains. Summary of the Invention

[0003] To address the aforementioned shortcomings in the prior art, this invention provides an aluminum alloy for preparing traction rods for train bogies and a method for preparing the same, which can effectively improve the alloy's performance.

[0004] To achieve the above objectives, the technical solution adopted by the present invention to solve its technical problem is as follows:

[0005] The purpose of this invention is to provide a method for preparing aluminum alloy for manufacturing traction rods of train bogies, comprising the following steps:

[0006] (1) Pure Al, Al-Zn, Al-Mg, Al-Cu, Al-Zr, Al-Ti, and Al-Y master alloys were heated and melted respectively, and then mixed, stirred and slag was removed to obtain alloy melt;

[0007] (2) Inert gas and refining agent are introduced from the bottom of the alloy melt, and then inert gas is introduced again after 10 to 15 minutes, and surface slag is removed.

[0008] (3) The alloy melt after step (2) is degassed and then sintered in a pulsed magnetic field environment of 1000-1500℃ and 0.5-2.5T for 15-30 minutes.

[0009] (4) After sintering, the aluminum alloy billet is cooled and treated with plasma for 10-20 minutes during the cooling process. After cooling, it is poured to obtain the aluminum alloy billet.

[0010] Furthermore, the inert gas introduced in step (2) is either Ar or N2.

[0011] Furthermore, in step (2), the flow rate of the inert gas introduced for the second time is greater than the flow rate of the inert gas introduced for the first time.

[0012] Furthermore, the flow rate of the inert gas introduced twice in step (2) is 0.5 to 15 L / min.

[0013] Furthermore, the refining agent used in step (2) is JGJ-1, SJH-JLJ or LHJ-450.

[0014] Furthermore, in step (3), degassing is performed using ultrasound with an ultrasonic power of 1-3 kW and a frequency of 20-30 kHz.

[0015] Furthermore, in step (3), the calcination temperature is 1000-1200℃, the magnetic field strength is 0.5-1.5T, and the calcination time is 15-20min.

[0016] Furthermore, the cooling method in step (4) is air cooling.

[0017] Furthermore, in step (4), the plasma discharge temperature is 20–80°C, and the discharge power density is 1–500 W / cm². 3 .

[0018] Another object of the present invention is to provide an aluminum alloy for manufacturing traction rods for train bogies, the aluminum alloy being prepared by the above method and comprising the following components by weight percentage:

[0019] Zn 5.8–7.6%, Mg 1.5–1.9%, Cu 2.0–2.5%, Zr 0.1–0.2%, Ti 0.04–0.15%, Y 0.05–0.5%, with the balance being Al and unavoidable impurities.

[0020] Another object of the present invention is to provide a traction rod for a train built-in bogie, the preparation method of which is as follows:

[0021] (1) Cast the above aluminum alloy to form a billet and remove the outer skin, heat to 380-450℃ and hold for 8-14 hours, then continue to heat to 450-490℃ and hold for 20-26 hours, and cool with water at room temperature;

[0022] (2) Heat the treated alloy billet to 380-450℃ and hold for 2-6 hours, then perform hot extrusion. The preheating temperature of the extrusion cylinder is 380-450℃, and the extrusion ratio is ≥10.

[0023] (3) Heat the alloy extrusion billet obtained in step (2) to 380-450℃ and hold for 2-6 hours;

[0024] (4) The alloy billet obtained in step (3) is subjected to superplastic die forging pre-forging, wherein the die preheating temperature is 380-450℃, the die forging temperature is 380-450℃, and the die forging rate is 10×10 -5 ~10×10 -2 mm / s, to obtain a pre-fractured aluminum alloy traction rod forging blank;

[0025] (5) Perform superplastic die forging on the aluminum alloy traction rod forging billet obtained in step (4). The die preheating temperature is 380-450℃, the die forging temperature is 380-450℃, and the die forging rate is 10×10. -5 ~10×10 -2 mm / s, to obtain a final forged aluminum alloy traction rod forging blank;

[0026] (6) The aluminum alloy traction rod forging blank obtained in step (5) is subjected to rough machining, heat treatment and fine machining in sequence to obtain the integral traction rod of the train's built-in bogie.

[0027] The beneficial effects of this invention are:

[0028] 1. This invention involves sintering at 1000–1500℃. Excessive temperature can lead to grain growth in the alloy, reducing its mechanical properties. Conversely, insufficient temperature can result in a porous and less dense alloy. Shorter sintering holding times can further improve the alloy's density, while holding times exceeding this range can also cause grain growth. Excessive grain growth alters the alloying positions and forms, weakening or reducing the alloying effect and changing the phase microstructure.

[0029] Furthermore, during rapid sintering, the high heating rate and short holding time limit the phase transformation process, enabling the desired phase combination to be achieved. By controlling the phase combination through specific sintering processes, combined with the pinning and alloying effects of Al3Y particles, the phase combination tendency is enhanced, achieving organic bonding between the two phases and significantly optimizing alloy properties.

[0030] 2. By applying a pulsed magnetic field during the alloy sintering process, the pinning effect between solute atoms and dislocations can be reduced, thereby reducing defects inside the alloy, promoting the diffusion of atoms inside the alloy, improving the uneven distribution of the microstructure in the alloy, and enhancing the service performance of the alloy.

[0031] 3. This invention first introduces inert gas and a refining agent into the alloy melt from the bottom, allowing the refining agent to react with the melt from bottom to top for refining treatment, thereby improving the refining effect of the alloy. Then, inert gas is continued to be introduced into the alloy melt from the bottom. During this process, bubbles will begin to form at the bottom of the melt. These bubbles float from the bottom to the top, performing a refining and degassing treatment. This process carries away the suspended slag produced during refining from the bottom of the melt, allowing the slag to float on the surface of the melt, thus significantly reducing the inclusion content in the resulting alloy. Detailed Implementation

[0032] The specific embodiments of the present invention are described below to enable those skilled in the art to understand the present invention. However, it should be understood that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, various changes are obvious as long as they are within the spirit and scope of the present invention as defined and determined by the appended claims. All inventions utilizing the concept of the present invention are protected.

[0033] Example 1

[0034] An aluminum alloy for manufacturing traction rods for train bogies comprises the following components by weight percentage:

[0035] The aluminum alloy comprises 5.8% Zn, 1.5% Mg, 2.0% Cu, 0.1% Zr, 0.04% Ti, and 0.05% Y, with the balance being Al and unavoidable impurities. The preparation method of this aluminum alloy is as follows:

[0036] (1) Pure Al, Al-Zn, Al-Mg, Al-Cu, Al-Zr, Al-Ti, and Al-Y master alloys were heated and melted respectively, and then mixed, stirred and slag was removed to obtain alloy melt;

[0037] (2) Introduce the mixed inert gas nitrogen and refining agent JGJ-1 from the bottom of the alloy melt at a flow rate of 1.5 L / min, and then continue to introduce inert gas nitrogen at a flow rate of 8.5 L / min after 10 min, and remove the surface scum.

[0038] (3) The alloy melt after step (2) was degassed by ultrasonic treatment and then sintered in a pulsed magnetic field environment of 1200℃ and 1.2T for 15min; the ultrasonic power was 3Kw and the frequency was 20KHz.

[0039] (4) After sintering, the aluminum alloy billet is air-cooled and treated with plasma for 15 minutes during the cooling process. After further cooling, it is poured to obtain the aluminum alloy billet. The plasma discharge temperature is 30℃ and the discharge power density is 200W / cm³. 3 .

[0040] The specific process for using the above-mentioned aluminum alloy to fabricate the train's internal bogie traction rod is as follows:

[0041] (1) Casting alloy billet: The aluminum alloy billet was prepared by the above method.

[0042] (2) Homogenization treatment: Remove the outer skin of the aluminum alloy billet obtained in step (1), heat it to 380℃ and hold it for 12 hours, then continue to heat it to 490℃ and hold it for 20 hours, and then cool it with water at room temperature.

[0043] (3) Hot extrusion: The alloy billet obtained in step (2) is heated to 450°C and held for 4 hours for hot extrusion. The preheating temperature of the extrusion cylinder is 380°C and the extrusion ratio is ≥10.

[0044] (4) Preheating: Heat the alloy extrusion billet obtained in step (3) to 380℃ and hold for 2-6 hours.

[0045] (5) Superplastic pre-forging: The alloy billet obtained in step (4) is placed in a pre-forging die for superplastic forging to obtain an aluminum alloy traction rod forging billet. The die preheating temperature is 450℃, the forging temperature is 450℃, and the forging rate is 10×10. -5 mm / s.

[0046] (6) Superplastic forging final forging: The alloy billet obtained in step (5) is placed in the final forging die for superplastic forging to obtain the aluminum alloy traction rod forging billet. The die preheating temperature is 450℃, the forging temperature is 380℃, and the forging rate is 10×10. -5 mm / s.

[0047] (7) Rough machining: The aluminum alloy traction rod forging blank obtained in step (6) is rough machined according to the rough machining drawing of the traction rod.

[0048] (8) Heat treatment: Heat the rough-machined aluminum alloy traction rod obtained in step (7) to 500℃ and keep it at that temperature for 3 hours, then cool it with water at room temperature; then heat it to 140℃ and keep it at that temperature for 26 hours, then air cool it.

[0049] (9) Finishing: The aluminum alloy traction rod obtained in step (8) is finished according to the traction rod finishing drawing.

[0050] Example 2

[0051] An aluminum alloy for manufacturing traction rods for train bogies comprises the following components by weight percentage:

[0052] The aluminum alloy comprises 7.6% Zn, 1.9% Mg, 2.5% Cu, 0.2% Zr, 0.15% Ti, and 0.5% Y, with the balance being Al and unavoidable impurities. The preparation method of this aluminum alloy is as follows:

[0053] (1) Pure Al, Al-Zn, Al-Mg, Al-Cu, Al-Zr, Al-Ti, and Al-Y master alloys were heated and melted respectively, and then mixed, stirred and slag was removed to obtain alloy melt;

[0054] (2) Introduce the mixed inert gas nitrogen and refining agent JGJ-1 from the bottom of the alloy melt at a flow rate of 0.5 L / min, and then continue to introduce inert gas nitrogen at a flow rate of 6 L / min after 10 min, and remove the surface scum.

[0055] (3) The alloy melt after step (2) was degassed by ultrasonic treatment and then sintered in a pulsed magnetic field environment of 1000℃ and 0.5T for 15 minutes; the ultrasonic power was 2Kw and the frequency was 30KHz.

[0056] (4) After sintering, the aluminum alloy billet is air-cooled and treated with plasma for 15 minutes during the cooling process. After further cooling, it is poured to obtain the aluminum alloy billet. The plasma discharge temperature is 20℃ and the discharge power density is 100W / cm³. 3 .

[0057] The specific process for using the above-mentioned aluminum alloy to fabricate the train's internal bogie traction rod is as follows:

[0058] (1) Casting alloy billet: The aluminum alloy billet was prepared by the above method.

[0059] (2) Homogenization treatment: Remove the outer skin of the aluminum alloy billet obtained in step (1), heat it to 380℃ and hold it for 14 hours, then continue to heat it to 450℃ and hold it for 26 hours, and then cool it with water at room temperature.

[0060] (3) Hot extrusion: The alloy billet obtained in step (2) is heated to 450°C and held for 2 hours for hot extrusion. The preheating temperature of the extrusion cylinder is 400°C and the extrusion ratio is ≥10.

[0061] (4) Preheating: Heat the alloy extrusion billet obtained in step (3) to 380°C and hold for 5 hours.

[0062] (5) Superplastic pre-forging: The alloy billet obtained in step (4) is placed in a pre-forging die for superplastic forging to obtain an aluminum alloy traction rod forging billet. The die preheating temperature is 450℃, the forging temperature is 400℃, and the forging rate is 10×10. -2 mm / s.

[0063] (6) Superplastic forging final forging: The alloy billet obtained in step (5) is placed in the final forging die for superplastic forging to obtain the aluminum alloy traction rod forging billet. The die preheating temperature is 450℃, the forging temperature is 380℃, and the forging rate is 10×10. -2 mm / s.

[0064] (7) Rough machining: The aluminum alloy traction rod forging blank obtained in step (6) is rough machined according to the rough machining drawing of the traction rod.

[0065] (8) Heat treatment: Heat the rough-machined aluminum alloy traction rod obtained in step (7) to 450℃ and keep it at that temperature for 6 hours, then cool it with water at room temperature; then heat it to 110℃ and keep it at that temperature for 20 hours, then air cool it.

[0066] (9) Finishing: The aluminum alloy traction rod obtained in step (8) is finished according to the traction rod finishing drawing.

[0067] Example 3

[0068] An aluminum alloy for manufacturing traction rods for train bogies comprises the following components by weight percentage:

[0069] The aluminum alloy comprises 6.2% Zn, 1.8% Mg, 2.2% Cu, 0.15% Zr, 0.06% Ti, and 0.2% Y, with the balance being Al and unavoidable impurities. The preparation method of this aluminum alloy is as follows:

[0070] (1) Pure Al, Al-Zn, Al-Mg, Al-Cu, Al-Zr, Al-Ti, and Al-Y master alloys were heated and melted respectively, and then mixed, stirred and slag was removed to obtain alloy melt;

[0071] (2) Introduce the mixed inert gas nitrogen and refining agent JGJ-1 from the bottom of the alloy melt at a flow rate of 5 L / min, and then continue to introduce inert gas nitrogen at a flow rate of 15 L / min after 10 min, and remove the surface scum.

[0072] (3) The alloy melt after step (2) was degassed by ultrasound and then sintered in a pulsed magnetic field environment of 1500℃ and 2.5T for 15 minutes; the ultrasonic power was 3Kw and the frequency was 30KHz.

[0073] (4) After sintering, the aluminum alloy billet is air-cooled and treated with plasma for 15 minutes during the cooling process. After further cooling, it is poured to obtain the aluminum alloy billet. The plasma discharge temperature is 40℃ and the discharge power density is 100W / cm³. 3 .

[0074] The specific process for using the above-mentioned aluminum alloy to fabricate the train's internal bogie traction rod is as follows:

[0075] (1) Casting alloy billet: The aluminum alloy billet was prepared by the above method.

[0076] (2) Homogenization treatment: Remove the outer skin of the aluminum alloy billet obtained in step (1), heat it to 420℃ and hold it for 10 hours, then continue to heat it to 450℃ and hold it for 20 hours, and then cool it with water at room temperature.

[0077] (3) Hot extrusion: The alloy billet obtained in step (2) is heated to 380℃ and held for 5 hours for hot extrusion. The preheating temperature of the extrusion cylinder is 400℃ and the extrusion ratio is ≥10.

[0078] (4) Preheating: Heat the alloy extrusion billet obtained in step (3) to 380°C and hold for 6 hours.

[0079] (5) Superplastic pre-forging: The alloy billet obtained in step (4) is placed in a pre-forging die for superplastic forging to obtain an aluminum alloy traction rod forging billet. The die preheating temperature is 400℃, the forging temperature is 420℃, and the forging rate is 10×10. -3 mm / s.

[0080] (6) Superplastic forging final forging: The alloy billet obtained in step (5) is placed in the final forging die for superplastic forging to obtain the aluminum alloy traction rod forging billet. The die preheating temperature is 420℃, the forging temperature is 450℃, and the forging rate is 10×10. -3 mm / s.

[0081] (7) Rough machining: The aluminum alloy traction rod forging blank obtained in step (6) is rough machined according to the rough machining drawing of the traction rod.

[0082] (8) Heat treatment: Heat the rough-machined aluminum alloy traction rod obtained in step (7) to 450℃ and keep it at that temperature for 5 hours, then cool it with water at room temperature; then heat it to 130℃ and keep it at that temperature for 20 hours, then air cool it.

[0083] (9) Finishing: The aluminum alloy traction rod obtained in step (8) is finished according to the traction rod finishing drawing.

[0084] Comparative Example 1

[0085] Compared with Example 1, in step (2), only one inert gas was introduced, and the refining agent was not added from the bottom of the alloy melt. The rest of the process was the same as in Example 1.

[0086] Comparative Example 2

[0087] Compared with Example 1, no pulsed magnetic field was applied during the sintering process in step (3), while the rest of the process was the same as in Example 1.

[0088] Comparative Example 3

[0089] Compared with Example 1, the sintering temperature in step (3) is 1200℃, the sintering pressure is 30MPa, and the time is 10min. The rest of the process is the same as in Example 1.

[0090] Comparative Example 4

[0091] Compared with Example 1, step (4) did not involve plasma treatment during the cooling process, while the rest of the process was the same as in Example 1.

[0092] Performance testing

[0093] The tensile strength, yield strength and elongation after fracture of the traction rods prepared in Examples 1-3 and Comparative Examples 1-4 were tested using conventional methods well known in the art, and the results are shown in Table 1.

[0094] Table 1 Traction Rod Performance

[0095]

[0096]

[0097] According to the test results in Table 1, the traction rod prepared using the technical solution of this application has significantly better overall performance in terms of tensile strength, yield strength and elongation after fracture than comparative examples 1 to 4, with example 1 showing the best technical effect.

[0098] For Comparative Examples 1-4, Comparative Example 1 changed the way the refining agent was added and the number of times it was vented, which may have resulted in an excessively high content of impurities and bubbles in the alloy, affecting the overall performance of the alloy. Comparative Examples 2 and 3 changed the sintering method of the alloy, which had a significant impact on the alloy's performance, but it can be seen that the performance of the product in Comparative Example 3 is significantly better. Although Comparative Example 4 only lacked plasma treatment during the cooling process, it still affected the performance of the product.

[0099] It is evident that the method for preparing the alloy using the specially constructed alloy of this invention can effectively reduce internal defects of the alloy, promote the diffusion of atoms within the alloy, improve the uneven distribution of the microstructure in the alloy, and enhance the service performance of the alloy, thereby obtaining products with high tensile strength, high elongation after fracture, and high yield strength.

[0100] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing an aluminum alloy for preparing a traction rod of a train built-in bogie, characterized in that: The following steps are involved: (1) Pure Al, Al-Zn, Al-Mg, Al-Cu, Al-Zr, Al-Ti, and Al-Y master alloys are heated and melted respectively, and then mixed, stirred, and slag removed to obtain alloy melts; (2) introducing a mixed inert gas and refining agent from the bottom of the alloy melt, and then continuing to introduce inert gas after 10 to 15 minutes, and removing surface slag; (3) degassing the alloy melt after the treatment in step (2), and then sintering it in a pulsed magnetic field environment of 1000-1500° C. and 0.5-2.5 T for 15-30 min; (4) After sintering, the aluminum alloy ingot is cooled and treated with plasma for 10 to 20 minutes during the cooling process, and then poured after cooling to obtain the aluminum alloy ingot.

2. The preparation method according to claim 1, characterized in that: The inert gas introduced twice in step (2) is Ar or N2.

3. The preparation method according to claim 1, characterized in that: The flow rate of the inert gas introduced for the second time in step (2) is greater than the flow rate of the inert gas introduced for the first time.

4. The preparation method according to claim 3, characterized in that: The flow rate of the inert gas introduced twice in step (2) is 0.5 to 15 L / min.

5. The preparation method according to claim 1, characterized in that: The refining agent used in step (2) is JGJ-1, SJH-JLJ or LHJ-450.

6. The preparation method according to claim 1, characterized in that: In step (3), degassing is performed by ultrasonic method.

7. The preparation method according to claim 1, characterized in that: The calcination temperature in step (3) is 1000-1200° C., the magnetic field intensity is 0.5-1.5 T, and the calcination time is 15-20 min.

8. The preparation method according to claim 1, characterized in that: In step (4), the plasma discharge temperature is 20 to 80°C, and the discharge power density is 1 to 500 W / cm 3 .

9. An aluminum alloy for preparing a traction rod for a train built-in bogie, characterized in that: The aluminum alloy is prepared by the method according to any one of claims 1 to 8, and comprises the following components in weight percentage: Zn 5.8~7.6%, Mg 1.5~1.9%, Cu 2.0~2.5%, Zr 0.1~0.2%, Ti 0.04~0.15%, Y 0.05~0.5%, and the balance is Al and inevitable impurities.

10. A train built-in bogie traction rod, characterized in that: The preparation method is as follows: (1) Casting the aluminum alloy of claim 9 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 pre-cut aluminum alloy traction rod forging blank; (5) The aluminum alloy traction rod 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, and the aluminum alloy traction rod forging blank with final forging treatment is obtained; (6) The aluminum alloy traction rod forging blank obtained in step (5) is subjected to rough processing, heat treatment and fine processing in sequence to obtain the integral traction rod of the train built-in bogie.

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