Synchronous stress elimination method and device for axle laser additive repair

Abstract

The invention discloses a synchronous stress eliminating method and device for axle laser additive repair, and belongs to the technical field of laser cladding. The synchronous stress eliminating method for axle laser additive repairing comprises the following steps that a repairing area of an axle is pretreated; a coating material is placed in the repairing area of the axle, cladding laser irradiates the coating material to prepare a cladding coating, and the coating material and the cladding laser move along the repairing path of the axle in a coaxial powder feeding mode; and an ultrafast laser beam is adopted to conduct shot peening impact on the cladding coating, and the ultrafast laser beam moves along with movement of the repairing path of the cladding laser, so that the ultrafast laser beam can conduct shot peening impact on the cladding coating in the high-temperature state. The synchronous stress relieving method for axle laser additive repair has the advantages that the working procedures are simplified, the machining time is shortened, the energy utilization efficiency is improved, the material cost and the operation complexity are reduced, and the shot blasting treatment effect is enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of laser cladding, and in particular to a synchronous stress elimination method and device for laser additive repair of an axle. Background Art

[0002] Axles are core components of railway vehicles. They are not only expensive, but also extremely safe. During use, axles may have defects such as dimensional deviation and surface scratches. Timely repair of these defects is of great significance to ensure the safe operation of vehicles. The axles of railway vehicles are mainly subjected to periodic bending stress, and the stress distribution on the axle surface has a decisive influence on its fatigue life.

[0003] Laser cladding technology is a commonly used repair method, but during this process, the axle will undergo a transition from metal melting to solidification, and then the axle surface will cool rapidly, generating residual stress. These residual stresses have a significant negative impact on the mechanical properties of the axle, especially its fatigue performance. When the residual stress exceeds the tensile strength of the material, the axle may even crack, seriously affecting the service life and safety of the axle.

[0004] In order to solve this problem, some studies have proposed a method and device for improving surface properties by combining laser cladding and laser shot peening technology. For example, patent publication number CN101392382B discloses a method for post-processing a cladding coating by laser shot peening technology, aiming to change the residual stress distribution in the cladding layer to reduce the level of residual tensile stress.

[0005] However, this method has the following defects: laser cladding and laser shot peening are carried out in steps, first laser cladding is completed at one workstation, and then the workpiece is transferred to another workstation for laser shot peening. This operation mode not only increases the complexity of the process, but also prolongs the processing time. More importantly, since the cladding coating has cooled during laser shot peening, an absorption film is required to absorb the laser energy. This not only fails to achieve efficient use of energy, but also increases material costs and operational complexity. In addition, the cooled coating may have formed a relatively stable residual stress distribution, which may reduce the effect of subsequent shot peening. Summary of the invention

[0006] The purpose of the present invention is to provide a synchronous stress elimination method and device for laser additive repair of an axle, which has the advantages of simplifying the process, shortening the processing time, improving energy utilization efficiency, reducing material costs and operation complexity, and enhancing the shot peening effect.

[0007] In a first aspect, the present invention provides a method for synchronous stress relief of axle laser additive repair, comprising the following steps: Pre-treat the repair area of ​​the axle; Placing a coating material in the repair area of ​​the axle, and irradiating the coating material with a cladding laser to prepare a cladding coating, and the coating material and the cladding laser are moved along the repair path of the axle in a coaxial powder feeding manner; An ultrafast laser beam is used to perform shot peening on the cladding coating, and the ultrafast laser beam moves along the repair path of the cladding laser, so that the ultrafast laser beam can perform shot peening on the cladding coating in a high temperature state.

[0008] The synchronous stress elimination method for laser additive repair of an axle provided by the present invention is performed by pre-treating the repair area of ​​the axle; placing a coating material in the repair area of ​​the axle, and preparing a cladding coating by irradiating the coating material with a cladding laser, and the coating material and the cladding laser are moved along the repair path of the axle by coaxial powder feeding; an ultrafast laser beam is used to shot peen the cladding coating, and the ultrafast laser beam moves along the repair path of the cladding laser, so that the ultrafast laser beam can shot peen the cladding coating in a high temperature state. By performing laser cladding and laser shot peening simultaneously, the process is simplified and the processing time is shortened. At the same time, shot peening the cladding coating in a high temperature state improves energy utilization efficiency and reduces material cost and operation complexity. In addition, shot peening is performed when the residual stress distribution is not yet completely stable, which enhances the effect of shot peening.

[0009] Furthermore, the use of an ultrafast laser beam to perform shot peening on the cladding coating comprises the following steps: Detect the real-time temperature of the cladding coating; When the real-time temperature reaches the preset temperature range, the cladding coating is shot peened using an ultrafast laser beam.

[0010] By adopting the above technical solution, by detecting the real-time temperature of the cladding coating, it can be ensured that the temperature of the cladding coating can reach a preset temperature range during shot peening, which helps to ensure the effect of shot peening.

[0011] Furthermore, the preset temperature range t is 400°C-600°C.

[0012] Furthermore, the use of an ultrafast laser beam to perform shot peening on the cladding coating comprises the following steps: The spacing distance d between the action area of ​​the ultrafast laser beam and the cladding laser is adjusted according to the real-time temperature, wherein the spacing distance d is 5 mm-50 mm.

[0013] By adopting the above technical solution, the cladding coating can be effectively shot peened when it is in a high temperature state, thereby reducing the generation of residual stress. Specifically, when the temperature detection component detects the real-time temperature of the cladding coating, the controller adjusts the distance between the action area of ​​the ultrafast laser beam and the cladding laser according to the temperature to ensure that the shot peening is performed within an appropriate temperature range. In this way, the stress can be eliminated by shot peening before the cladding coating is completely cooled, thereby improving the mechanical properties of the axle.

[0014] Furthermore, the method further comprises the following steps: The repetition frequency f of the ultrafast laser beam is adjusted according to the moving speed v of the cladding laser, and the spot width of the ultrafast laser beam is d2, wherein f≥v / d2.

[0015] The above technical solution is adopted to adjust the repetition frequency of the ultrafast laser beam to match the moving speed of the cladding laser, ensuring that the ultrafast laser beam can timely peen the cladding coating during the laser cladding process, thereby ensuring that the ultrafast laser action area completely covers the laser cladding area. This measure can effectively eliminate stress when the coating is in a high temperature state, avoid residual stress in the coating after cooling, and thus improve the fatigue performance of the axle.

[0016] Furthermore, the method further comprises the following steps: The spot diameter d2 of the ultrafast laser beam is adjusted according to the spot diameter d1 of the cladding laser, wherein d2=d1.

[0017] By adopting the above technical solution, by adjusting the spot diameter of the ultrafast laser beam to make it equal to the spot diameter of the cladding laser beam, it can be ensured that during the cladding process, the ultrafast laser beam can fully cover the entire area of ​​the cladding coating, thereby achieving effective shot peening impact.

[0018] Furthermore, the axle is an axle of a rail vehicle.

[0019] Furthermore, the laser power p of the cladding laser is 2kW-6kW, the spot diameter d1 is 2mm-8mm, the powder laser deposition rate md is 5g / min-30g / min, and the cladding laser spot moving speed v is 8mm / s-25mm / s; the pulse width w of the ultrafast laser beam is 5ns-10ns, and the pulse energy e is 1J-8J.

[0020] By adopting the above technical scheme, by controlling the processing parameters, the residual stress caused by metal solidification during the process can be avoided to cause cracks, and the residual stress of additive repair can be controlled to the compressive stress level, thereby eliminating the negative impact of the residual tensile stress generated by additive repair on the fatigue life of the axle, and playing a strengthening role, thereby improving the fatigue life of the axle.

[0021] Furthermore, the pretreatment of the repair area of ​​the axle includes the following steps: Use grinding to remove the fatigue layer of metal on the surface, clean it with anhydrous alcohol, and blow it dry for later use.

[0022] In a second aspect, the present invention provides a device for implementing a synchronous stress elimination method for laser additive repair of an axle, comprising: A first motion mechanism, on which a cladding laser projection assembly and a second motion mechanism are provided, wherein the first motion mechanism is used to drive the cladding laser projection assembly and the second motion mechanism to move horizontally; an impact laser projection assembly, disposed on the second motion mechanism, the second motion mechanism being capable of driving the impact laser projection assembly to approach or move away from the cladding laser projection assembly; A temperature detection member, mounted on the impact laser projection assembly, for detecting the temperature of an impact area, wherein the impact area is an area on the axle irradiated by the ultrafast laser beam at the current moment; The controller is used to control the first motion mechanism to drive the cladding laser projection assembly and the impact laser projection assembly to move simultaneously, so that the cladding laser emitted by the cladding laser projection assembly and the ultrafast laser beam emitted by the impact laser projection assembly successively perform cladding treatment and shot peening treatment on the axle; the controller is also used to control the second motion mechanism to adjust the distance between the impact laser projection assembly and the cladding laser projection assembly when the temperature of the impact area is not within a preset temperature range.

[0023] The above technical solution realizes the simultaneous processing of cladding and shot peening, avoiding the complicated operation process of the prior art that requires step-by-step processing at different workstations. The effect of shot peening is ensured by real-time temperature monitoring and automatic adjustment of the distance between laser components, thereby improving the mechanical properties and fatigue life of the axle. Therefore, the device of the present application has significant advantages in improving the quality and efficiency of repair.

[0024] As can be seen from the above, the synchronous stress elimination method for laser additive repair of an axle provided by the present invention is to pre-treat the repair area of ​​the axle; place a coating material in the repair area of ​​the axle, and prepare a cladding coating by irradiating the coating material with a cladding laser, and the coating material and the cladding laser are moved along the repair path of the axle by coaxial powder feeding; an ultrafast laser beam is used to shot peen the cladding coating, and the ultrafast laser beam moves along the repair path of the cladding laser, so that the ultrafast laser beam can shot peen the cladding coating in a high temperature state. By performing laser cladding and laser shot peening simultaneously, the process is simplified and the processing time is shortened. At the same time, shot peening the cladding coating in a high temperature state improves energy utilization efficiency and reduces material cost and operation complexity. In addition, shot peening is performed when the residual stress distribution is not yet completely stable, which enhances the effect of shot peening.

[0025] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or be understood by implementing the embodiments of the present application. The purpose and other advantages of the present application can be achieved and obtained through the structures specifically pointed out in the written description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a flow chart of a method for synchronous stress relief of laser additive repair of an axle proposed by the present invention.

[0027] Figure 2 The present invention is a schematic structural diagram of a device for implementing a synchronous stress elimination method for laser additive repair of an axle.

[0028] Figure 3 for Figure 2 The electronic control framework diagram of the device for implementing the synchronous stress relief method of laser additive repair of axles.

[0029] In the accompanying drawings: 1. first motion mechanism; 11. cladding laser projection assembly; 121. second motion mechanism; 122. impact laser projection assembly; 2. temperature detection component; 3. controller. DETAILED DESCRIPTION

[0030] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0031] The disclosure below provides many different embodiments or examples to implement different structures of the present invention. In order to simplify the disclosure of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention. In addition, the present invention can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed.

[0032] The axle of a railway vehicle is one of its core components, with high value and important safety. During use, the axle may have defects such as dimensional deviation and surface scratches. If these defects are not repaired in time, they will affect the safe operation of the vehicle. Although the existing laser cladding technology can repair the defects on the surface of the axle to a certain extent, during the cladding process, the surface of the axle will cool rapidly, generating residual stress, which will affect the mechanical properties and fatigue life of the axle. In particular, when the residual stress exceeds the tensile strength of the material, cracks may appear on the axle.

[0033] Reference Figure 1 The invention discloses a synchronous stress elimination method for laser additive repair of axles, which is mainly used for laser additive repair of axles, and has the advantages of simplifying the process, shortening the processing time, improving the energy utilization efficiency, reducing the material cost and operation complexity, and enhancing the shot peening effect. It is worth noting that the axles repaired by laser additive repair can be but not limited to axles.

[0034] In one embodiment, a method for simultaneous stress relief of laser additive repair of an axle includes the following steps: S100, pre-treating the repair area of ​​the axle; S200, placing a coating material in the repair area of ​​the axle, and irradiating the coating material with a cladding laser to prepare a cladding coating, and the coating material and the cladding laser are moved along the repair path of the axle in a coaxial powder feeding manner; S300, using an ultrafast laser beam to perform shot peening on the cladding coating, and the ultrafast laser beam moves along the repair path of the cladding laser, so that the ultrafast laser beam can perform shot peening on the cladding coating in a high temperature state.

[0035] Specifically, the ultrafast laser beam action area is located after the cladding coating, that is, the ultrafast laser beam action area is the process of the cladding coating metal solidifying but not completely cooling. By adjusting the pulse energy of the ultrafast laser, the impact force of the ultrafast laser can be adjusted. When the impact stress generated on the surface of the cladding metal exceeds the yield strength of the cladding metal at this temperature, the laser cladding metal can be plastically deformed. The residual stress generated by laser cladding will be eliminated during the metal deformation process, thereby achieving the effect of eliminating residual stress.

[0036] As can be seen from the above, the synchronous stress elimination method for laser additive repair of an axle provided by the present invention is to pre-treat the repair area of ​​the axle; place a coating material in the repair area of ​​the axle, and prepare a cladding coating by irradiating the coating material with a cladding laser, and the coating material and the cladding laser are moved along the repair path of the axle by coaxial powder feeding; an ultrafast laser beam is used to shot peen the cladding coating, and the ultrafast laser beam moves along the repair path of the cladding laser, so that the ultrafast laser beam can shot peen the cladding coating in a high temperature state. By performing laser cladding and laser shot peening simultaneously, the process is simplified and the processing time is shortened. At the same time, shot peening the cladding coating in a high temperature state improves energy utilization efficiency and reduces material cost and operation complexity. In addition, shot peening is performed when the residual stress distribution is not yet completely stable, which enhances the effect of shot peening.

[0037] In the laser additive repair process, the temperature of the cladding coating is a key factor affecting the shot peening effect. By detecting the temperature of the cladding coating in real time, it is possible to ensure that the shot peening is performed within the optimal temperature range, thereby achieving the best stress relief effect. Specifically, when the real-time temperature of the cladding coating reaches the preset temperature range, the ultrafast laser beam performs shot peening on the cladding coating, which can effectively reduce the residual stress in the cladding coating and improve the mechanical properties and fatigue life of the coating.

[0038] To this end, in one embodiment, the use of an ultrafast laser beam to perform shot peening on the cladding coating includes the following steps: Detect the real-time temperature of the cladding coating; When the temperature reaches the preset temperature range, the cladding coating is shot peened using an ultrafast laser beam.

[0039] Specifically, a high-precision temperature sensor is used to monitor the temperature of the cladding coating in real time, and the temperature data is transmitted to the control system. When it is detected that the temperature of the cladding coating reaches the preset temperature range, the control system will trigger the ultrafast laser beam to perform shot peening on the cladding coating. In addition, the parameters of the ultrafast laser beam, such as pulse width, energy and frequency, can also be adjusted according to actual needs to ensure the effect of shot peening.

[0040] By adopting the above technical solution, by detecting the real-time temperature of the cladding coating, it can be ensured that the temperature of the cladding coating can reach a preset temperature range during shot peening, which helps to ensure the effect of shot peening.

[0041] In one embodiment, the preset temperature range t is 400°C-600°C.

[0042] Specifically, the preset temperature range is 400°C-600°C, which is determined based on the temperature characteristics and material characteristics of the cladding coating. Within this temperature range, the cladding coating is in a high temperature state, and the shot peening effect of the ultrafast laser beam is optimal, which is conducive to eliminating residual stress.

[0043] In one embodiment, shot peening the cladding coating using an ultrafast laser beam comprises the following steps: The spacing distance d between the action area of ​​the ultrafast laser beam and the cladding laser is adjusted according to the real-time temperature, wherein the spacing distance d is 5 mm-50 mm.

[0044] Specifically, the implementation methods of this technical feature may include but are not limited to the following: first, the action area of ​​the ultrafast laser beam may be changed by adjusting the motion trajectory of the second motion mechanism; second, the action area of ​​the ultrafast laser beam may be changed by adjusting the emission angle or focal length of the ultrafast laser beam. In addition, the power and frequency of the ultrafast laser beam may be dynamically adjusted in combination with the real-time data of the temperature detection element to achieve a more precise shot peening impact effect.

[0045] By adopting the above technical solution, the cladding coating can be effectively shot peened when it is in a high temperature state, thereby reducing the generation of residual stress. Specifically, when the temperature detection component detects the real-time temperature of the cladding coating, the controller adjusts the distance between the action area of ​​the ultrafast laser beam and the cladding laser according to the temperature to ensure that the shot peening is performed within an appropriate temperature range. In this way, the stress can be eliminated by shot peening before the cladding coating is completely cooled, thereby improving the mechanical properties of the axle.

[0046] In one embodiment, the method further comprises the following steps: The repetition frequency f of the ultrafast laser beam is adjusted according to the moving speed v of the cladding laser, and the spot width of the ultrafast laser beam is d2, wherein f≥v / d2.

[0047] The above technical solution is adopted to adjust the repetition frequency of the ultrafast laser beam to match the moving speed of the cladding laser, ensuring that the ultrafast laser beam can timely peen the cladding coating during the laser cladding process, thereby ensuring that the ultrafast laser action area completely covers the laser cladding area. This measure can effectively eliminate stress when the coating is in a high temperature state, avoid residual stress in the coating after cooling, and thus improve the fatigue performance of the axle.

[0048] In one embodiment, the method further comprises the following steps: The spot diameter d2 of the ultrafast laser beam is adjusted according to the spot diameter d1 of the cladding laser, wherein d2=d1.

[0049] Specifically, the control system can monitor the spot diameter of the cladding laser beam in real time and adjust the spot diameter of the ultrafast laser beam according to the monitoring results. For example, when the spot diameter of the cladding laser beam is 5mm, the control system will also adjust the spot diameter of the ultrafast laser beam to 5mm. In this way, it can be ensured that the ultrafast laser beam can always effectively perform shot peening on the cladding coating during the entire cladding process.

[0050] By adopting the above technical solution, by adjusting the spot diameter of the ultrafast laser beam to make it equal to the spot diameter of the cladding laser beam, it can be ensured that during the cladding process, the ultrafast laser beam can fully cover the entire area of ​​the cladding coating, thereby achieving effective shot peening impact.

[0051] In one embodiment, the axle is an axle of a railway vehicle.

[0052] Specifically, the laser cladding material used for axle repair can be an iron-based, nickel-based or cobalt-based laser cladding material, which is selected and adjusted according to the different raw materials of the axle to form a stable and defect-free cladding effect with the axle base material, and the mechanical properties must meet the technical index requirements of the axle as the selection principle.

[0053] In one of the embodiments, the laser power p of the cladding laser is 2kW-6kW, the spot diameter d1 is 2mm-8mm, the powder laser deposition rate md is 5g / min-30g / min, and the cladding laser spot moving speed v is 8mm / s-25mm / s; the pulse width w of the ultrafast laser beam is 5ns-10ns, and the pulse energy e is 1J-8J.

[0054] By adopting the above technical scheme, by controlling the processing parameters, the residual stress caused by metal solidification during the process can be avoided to cause cracks, and the residual stress of additive repair can be controlled to the compressive stress level, thereby eliminating the negative impact of the residual tensile stress generated by additive repair on the fatigue life of the axle, and playing a strengthening role, thereby improving the fatigue life of the axle.

[0055] In one embodiment, the pre-processing of the repair area of ​​the axle comprises the following steps: Use grinding to remove the fatigue layer of metal on the surface, clean it with anhydrous alcohol, and blow it dry for later use.

[0056] Reference Figure 2 , Attachment Figure 2The present invention also provides a device for implementing the synchronous stress elimination method of laser additive repair of axles in the above-mentioned embodiment, comprising: a first motion mechanism 1 on which a cladding laser projection assembly 11 and a second motion mechanism 121 are provided, the first motion mechanism 1 is used to drive the cladding laser projection assembly 11 and the second motion mechanism 121 to move horizontally; an impact laser projection assembly 122 is provided on the second motion mechanism 121, and the second motion mechanism 121 can drive the impact laser projection assembly 122 to approach or move away from the cladding laser projection assembly 11; a temperature detection component 2 is installed on the impact laser projection assembly 122 for detecting The temperature of the impact area is measured, and the impact area is the area on the axle irradiated by the ultrafast laser beam at the current moment; the controller 3 is used to control the first motion mechanism 1 to drive the cladding laser projection assembly 11 and the impact laser projection assembly 122 to move simultaneously, so that the cladding laser emitted by the cladding laser projection assembly 11 and the ultrafast laser beam emitted by the impact laser projection assembly 122 successively perform cladding treatment and shot peening impact treatment on the axle; the controller 3 is also used to control the second motion mechanism to adjust the distance between the impact laser projection assembly 122 and the cladding laser projection assembly 11 when the temperature of the impact area is not within the preset temperature range.

[0057] The above technical solution realizes the simultaneous processing of cladding and shot peening, avoiding the complicated operation process of the prior art that requires step-by-step processing at different workstations. The effect of shot peening is ensured by real-time temperature monitoring and automatic adjustment of the distance between laser components, thereby improving the mechanical properties and fatigue life of the axle. Therefore, the device of the present application has significant advantages in improving the quality and efficiency of repair.

[0058] In the description of this specification, the description with reference to the terms "one embodiment", "certain embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0059] The above are only some embodiments of the present invention. For those skilled in the art, several modifications and improvements can be made without departing from the creative concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A synchronous stress relief method for laser additive repair of an axle, characterized in that: The following steps are involved: Pre-treat the repair area of ​​the axle; Placing a coating material in the repair area of ​​the axle, and irradiating the coating material with a cladding laser to prepare a cladding coating, and the coating material and the cladding laser are moved along the repair path of the axle in a coaxial powder feeding manner; An ultrafast laser beam is used to perform shot peening on the cladding coating, and the ultrafast laser beam moves along the repair path of the cladding laser, so that the ultrafast laser beam can perform shot peening on the cladding coating in a high temperature state.

2. The synchronous stress relief method for laser additive repair of an axle according to claim 1 is characterized in that: The method of using an ultrafast laser beam to shot peen the cladding coating comprises the following steps: Detect the real-time temperature of the cladding coating; When the real-time temperature reaches the preset temperature range, the cladding coating is shot peened using an ultrafast laser beam.

3. The synchronous stress elimination method for laser additive repair of an axle according to claim 2 is characterized in that: The preset temperature range t is 400°C-600°C.

4. The synchronous stress elimination method for laser additive repair of an axle according to claim 2 is characterized in that: The method of using an ultrafast laser beam to shot peen the cladding coating comprises the following steps: The spacing distance d between the action area of ​​the ultrafast laser beam and the cladding laser is adjusted according to the real-time temperature, wherein the spacing distance d is 5 mm-50 mm.

5. The synchronous stress relief method for laser additive repair of an axle according to claim 1 is characterized in that: The method further comprises the following steps: The repetition frequency f of the ultrafast laser beam is adjusted according to the moving speed v of the cladding laser, and the spot width of the ultrafast laser beam is d2, wherein f≥v / d2.

6. The synchronous stress elimination method for laser additive repair of an axle according to claim 1 is characterized in that: The method further comprises the following steps: The spot diameter d2 of the ultrafast laser beam is adjusted according to the spot diameter d1 of the cladding laser, wherein d2=d1.

7. The synchronous stress relief method for laser additive repair of an axle according to claim 1 is characterized in that: The axle is an axle of a rail vehicle.

8. The synchronous stress relief method for laser additive repair of an axle according to claim 7, characterized in that: The laser power p of the cladding laser is 2kW-6kW, the spot diameter d1 is 2mm-8mm, the powder laser deposition rate md is 5g / min-30g / min, and the cladding laser spot moving speed v is 8mm / s-25mm / s; the pulse width w of the ultrafast laser beam is 5ns-10ns, and the pulse energy e is 1J-8J.

9. The synchronous stress relief method for laser additive repair of an axle according to claim 1, characterized in that: The pretreatment of the repair area of ​​the axle comprises the following steps: Use grinding to remove the fatigue layer of metal on the surface, clean it with anhydrous alcohol, and blow it dry for later use.

10. A device for implementing the synchronous stress relief method for laser additive repair of an axle according to any one of claims 1 to 9, characterized in that: include: A first motion mechanism (1) on which a cladding laser projection assembly (11) and a second motion mechanism (121) are provided, wherein the first motion mechanism (1) is used to drive the cladding laser projection assembly (11) and the second motion mechanism (121) to move horizontally; an impact laser projection assembly (122) disposed on the second motion mechanism (121), wherein the second motion mechanism (121) is capable of driving the impact laser projection assembly (122) to approach or move away from the cladding laser projection assembly (11); A temperature detection element (2) is mounted on the impact laser projection assembly (122) and is used to detect the temperature of an impact area, wherein the impact area is an area on the axle irradiated by the ultrafast laser beam at the current moment; The controller (3) is used to control the first motion mechanism (1) to drive the cladding laser projection assembly (11) and the impact laser projection assembly (122) to move simultaneously, so that the cladding laser emitted by the cladding laser projection assembly (11) and the ultrafast laser beam emitted by the impact laser projection assembly (122) successively perform cladding treatment and shot peening treatment on the axle; the controller (3) is also used to control the second motion mechanism to adjust the distance between the impact laser projection assembly (122) and the cladding laser projection assembly (11) when the temperature of the impact area is not within a preset temperature range.

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