A Laser-Ultrasonic Shot Peening Composite Strengthening Device and Method

Abstract

A laser-ultrasonic shot peening strengthening device and method disclosed by the present invention belong to the technical field of machining. The present invention includes an ultrasonic shot peening device, a laser heating device, a laser-ultrasonic shot peening composite strengthening fixture, and a workpiece fixing fixture. The ultrasonic shot peening device includes an ultrasonic generator, a vibration head, a horn, shot, an impact tool head, an impact outer cover, and an impact fixing cover plate. The laser heating device includes a laser generator, a laser galvanometer, and a galvanometer fixing bracket. The laser-ultrasonic shot peening composite strengthening fixture includes an impact outer cover, an impact cover plate, and a workpiece fixing cover plate. The present invention drives shot to move at high speed through ultrasonic vibration and impacts the surface of the specimen to achieve shot peening strengthening, reducing the floor area of the equipment; in addition, by combining the laser heating device with the shot peening strengthening device, laser heating is performed on the surface of the specimen, and then ultrasonic shot peening is performed on the specimen to further improve the shot peening strengthening effect. The present invention is more suitable for surface strengthening of ultra-high strength materials.

Description

Technical Field

[0001] The present invention relates to a laser-ultrasonic shot peening composite strengthening device and method, belonging to the technical field of machining. Background Art

[0002] Due to the improvement of service requirements, it is necessary to improve the fatigue resistance of key components. As the initiation and initial propagation region of fatigue cracks, the fatigue resistance of the surface material largely determines the service performance of the entire component. Therefore, in order to improve the fatigue resistance of components, it is necessary to optimize the existing processing technology. The most common method is to add a surface strengthening process after the processing procedure. The surface strengthening process generally causes local large plastic deformation on the surface, resulting in lattice distortion of the surface material, forming nano-crystalline / fine-grained materials, and at the same time changing surface integrity, including surface residual stress and surface roughness and other indicators, thereby improving the fatigue resistance of the surface material.

[0003] Shot peening, as one of the most common surface strengthening processes, impacts the material surface with high-speed marbles. Local large plastic deformation occurs in the contact area between the marbles and the surface material, forming pits on the surface, and at the same time introducing a large value of residual compressive stress and a fine-grained strengthening layer, which can significantly improve the fatigue resistance of key components. Therefore, it is widely used in the fields of aerospace and weapons. However, shot peening will also form crater pits on the surface, resulting in an increase in surface roughness. Especially under low-cycle fatigue conditions, shot peening will instead reduce the fatigue life of components. At the same time, the equipment required for shot peening is generally relatively expensive, severely restricting its wide application. Summary of the Invention

[0004] Aiming at the following problems existing in the prior art: (1) Shot peening leads to an increase in surface roughness; (2) Shot peening equipment is expensive and occupies a large area. The purpose of the present invention is to provide a laser-ultrasonic shot peening strengthening device and method, which drives marbles to move at high speed and impact the specimen surface through ultrasonic vibration to achieve shot peening and reduce the equipment footprint; in addition, by combining a laser heating device with the shot peening device, laser heating is performed on the specimen surface, and then ultrasonic shot peening is performed on the specimen to further improve the shot peening effect, which is more suitable for surface strengthening of ultra-high-strength materials.

[0005] The purpose of the present invention is achieved by the following technical solutions:

[0006] A laser-ultrasonic shot peening composite strengthening device disclosed by the present invention includes an ultrasonic shot peening device, a laser heating device, a laser-ultrasonic shot peening composite fixture, and a workpiece fixing fixture.

[0007] The ultrasonic shot peening device includes an ultrasonic generator, a vibration head, a horn, shot, an impact tool head, an impact outer cover, and an impact fixed cover plate. The ultrasonic signal generated by the ultrasonic generator is transmitted to the vibration head through an ultrasonic signal line, causing the vibration head to generate ultrasonic vibration. The horn amplifies the ultrasonic vibration amplitude on the vibration head and transmits it to the impact tool head, driving the impact tool head to generate ultrasonic vibration. The ultrasonic vibration of the impact tool head transmits energy to the shot on the impact tool head and drives the shot to move at high speed, impacting the workpiece above the impact tool head and achieving ultrasonic shot peening strengthening.

[0008] The laser heating device includes a laser generator, a laser galvanometer, and a galvanometer fixed bracket. The laser galvanometer is fixed to the test platform through the galvanometer fixed bracket and acts on the surface of the specimen with the laser generated by the laser generator, achieving the effect of locally heating the specimen at high speed. The galvanometer fixed bracket can be adjusted in the height direction to control the distance between the laser galvanometer and the workpiece, thereby controlling the laser heating effect.

[0009] The laser-ultrasonic shot peening composite strengthening fixture includes an impact outer cover, an impact cover plate, and a workpiece fixed cover plate. The impact outer cover is in clearance fit with the impact tool head and is tightly fitted with the impact cover plate through bolts to form an ultrasonic shot peening strengthening cavity. A through hole is reserved in the middle of the impact cover plate, and the shot impacts the surface of the specimen through the reserved through hole in the middle. The workpiece fixed cover plate is in clearance fit with the workpiece and is fixed to the impact cover plate through bolts, and the workpiece can rotate freely within the workpiece fixed cover plate.

[0010] The workpiece fixing fixture includes an electric spindle, a chuck, a tailstock, and an electric spindle support.

[0011] The electric spindle is fixed to the test platform through the electric spindle support, and the rotational movement of the electric spindle is transmitted to the workpiece through the chuck to control the rotational movement of the workpiece. The electric spindle support can be adjusted in the height direction to adjust the position of the electric spindle. The tailstock is fixed to the test platform and cooperates with the chuck to fix the tail end of the workpiece to prevent the workpiece from flexing.

[0012] A laser-ultrasonic shot peening composite strengthening method disclosed by the present invention is realized based on the above-mentioned laser-ultrasonic shot peening composite strengthening device. The laser-ultrasonic shot peening composite strengthening method disclosed by the present invention is as follows:

[0013] Fix the ultrasonic shot peening strengthening device to the test platform through a fixed sleeve, and connect the ultrasonic shot peening strengthening device to the ultrasonic generator through an ultrasonic signal wire to achieve the ultrasonic vibration of the impact tool head. Fix the electric spindle and the tailstock to the test platform, adjust the height of the electric spindle by adjusting the electric spindle bracket so that its axis is higher than the ultrasonic shot peening strengthening device. Fix the workpiece to the electric spindle through a chuck, and then adjust the electric spindle bracket again to lower the electric spindle to the upper surface of the shot peening strengthening device, and complete the clamping of the workpiece in cooperation with the tailstock. Fit the workpiece fixing cover plate that cooperates with the workpiece, and fix it to the impact cover plate through bolts. An ultrasonic shot peening strengthening cavity is formed among the workpiece, the workpiece fixing cover plate, the impact cover plate, the impact outer cover and the impact tool head. The shot peening occurs at high speed under the action of the impact tool head and impacts the surface of the workpiece to achieve surface strengthening. Fix the laser galvanometer to the galvanometer bracket, and adjust the position of the laser galvanometer through the galvanometer bracket so that the laser emitted by the galvanometer irradiates on the upper surface of the workpiece, and connect the laser galvanometer to the laser generator.

[0014] Turn on the electric spindle to make the workpiece rotate, then turn on the ultrasonic generator to start the ultrasonic shot peening strengthening device, and finally turn on the laser heating device to laser heat the surface of the specimen, and then perform ultrasonic shot peening on the specimen to achieve laser-ultrasonic shot peening composite strengthening.

[0015] Beneficial effects:

[0016] 1. A laser-ultrasonic shot peening composite strengthening device and method disclosed by the present invention combines two processes of ultrasonic shot peening and laser heating, improves the ultrasonic shot peening strengthening effect, and is more suitable for the surface strengthening of difficult-to-machine materials.

[0017] 2. A laser-ultrasonic shot peening composite strengthening device and method disclosed by the present invention, compared with the traditional shot peening strengthening process, uses a workpiece fixing cover plate to cooperate with the workpiece, is suitable for the composite strengthening of variable-diameter rod-shaped specimens, and has lower cost, smaller floor area and higher surface strengthening efficiency for achieving the surface strengthening of difficult-to-machine materials. Description of the drawings

[0018] Figure 1 It is a schematic diagram of a laser-ultrasonic shot peening composite strengthening process device and method disclosed by the present invention;

[0019] Figure 2 It is a working schematic diagram of a laser-ultrasonic shot peening composite strengthening process device and method disclosed by the present invention;

[0020] Figure 3 It is a schematic diagram of the ultrasonic shot peening strengthening device disclosed by the present invention;

[0021] Figure 4 It is a schematic diagram of the workpiece fixing fixture disclosed by the present invention;

[0022] Figure 5 Schematic diagram of the laser-ultrasonic shot peening composite strengthening fixture disclosed by the present invention;

[0023] Figure 6 Schematic diagram of the working of the workpiece fixing cover plate disclosed by the present invention;

[0024] Figure 7 Two-dimensional drawing of the size of the specimen workpiece disclosed by the present invention;

[0025] Wherein: 1 - test platform, 2 - fixed enamel plate, 3 - horn, 4 - fixed sleeve, 5 - vibration head, 6 - impact tool head, 7 - electric spindle, 8 - tailstock, 9 - center, 10 - tailstock shaft, 11 - impact housing, 12 - impact cover plate, 13 - workpiece fixing cover plate, 14 - specimen workpiece, 15 - laser scanning galvanometer, 16 - ultrasonic generator, 17 - laser generator, 18 - electric spindle support, 19 - laser scanning galvanometer fixing bracket, 20 - chuck. Specific embodiments

[0026] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0027] As Figure 1 shown, a laser-ultrasonic shot peening composite strengthening process device disclosed in this embodiment includes an ultrasonic shot peening device, a laser heating device, a laser-ultrasonic shot peening composite strengthening fixture, a workpiece fixing fixture, and a test platform. The power of the laser heating device is 300W, the pulse frequency is 80HZ, the shot peening pressure of the ultrasonic shot peening device is 0.3MPa, the shot peening intensity is 0.25A, and the two-dimensional drawing of the size of the specimen workpiece is as Figure 7 shown.

[0028] As Figure 3 shown, the ultrasonic shot peening device includes a fixed enamel plate 2, a horn 3, a fixed sleeve 4, a vibration head 5, and an impact tool head 6.

[0029] The vibration head is connected to the ultrasonic generator through an ultrasonic signal line and generates ultrasonic vibration. The ultrasonic vibration is transmitted to the impact tool head through the horn and the amplitude changes. The horn is fixedly connected to the fixed enamel plate, and the fixed enamel plate is further connected to the fixed sleeve 4 through bolts, and the fixed sleeve 4 is fixed to the test platform 1.

[0030] As Figure 4 shown, the workpiece fixing fixture includes an electric spindle 7, an electric spindle support 18, a chuck 20, a tailstock 8, a tailstock shaft 10, and a center 9.

[0031] The electric spindle 7 is fixed to the test platform through the electric spindle bracket 18, and the electric spindles 7 can be adjusted in the height direction. The chuck 20 is fixedly connected to the electric spindle 7 and fixes the workpiece through the clamping force, transmitting the torsional movement of the electric spindle 7 to the workpiece. The tailstock is fixed to the test platform, the center is fixedly connected to the tailstock shaft 10, and the tailstock shaft 10 is connected to the tailstock 8 through a lead screw. By adjusting the handle of the tailstock 8, the horizontal position of the center 9 is adjusted. The electric spindle 7 and the center 9 are coaxial to jointly fix the workpiece.

[0032] As Figure 5 shown, the laser-ultrasonic shot peening composite strengthening fixture includes an impact outer cover 11, an impact cover plate 12, and a workpiece fixing cover plate 13. Figure 6 It is a schematic diagram for fixing the working cover plate, including the workpiece fixing cover plate 13 and the specimen workpiece 14.

[0033] The impact outer cover 11 is fixed to the fixed enamel plate 2 by screws. The inner diameter of the impact outer cover 11 has a clearance fit with the impact tool head 6, and the fit clearance is smaller than the diameter of the shot. The impact cover plate 12 is fixed to the impact outer cover 11. The workpiece fixing cover plate is composed of two identical parts, and the shape profile of the workpiece fixing cover plate is the same as the profile of the workpiece. As Figure 6 shown, it is fixed to the impact cover plate 12 by screws. An ultrasonic shot peening strengthening cavity is formed between the workpiece, the workpiece fixing cover plate 13, the impact cover plate 12, the impact outer cover 11, and the impact tool head 6. The impact tool head 6 transmits energy to the shot through ultrasonic vibration, causing the shot to reciprocate in the ultrasonic shot peening strengthening cavity and impact the surface of the workpiece to achieve the surface strengthening effect.

[0034] As Figure 1 shown, the laser heating device includes a laser galvanometer 15, a laser galvanometer fixing bracket 19, and a laser generator 17.

[0035] The laser galvanometer is fixed to the test platform through the laser galvanometer bracket. The laser galvanometer bracket 19 has freedom in the height direction and can adjust the distance between the laser galvanometer and the workpiece.

[0036] A laser-ultrasonic shot peening composite strengthening method disclosed in this embodiment is realized based on the above-mentioned laser-ultrasonic shot peening composite strengthening device. A laser-ultrasonic shot peening composite strengthening method disclosed in this embodiment is as follows:

[0037] Fix the ultrasonic shot peening strengthening device to the test platform through the fixed sleeve 4, and connect the ultrasonic shot peening strengthening device to the ultrasonic generator 16 through the ultrasonic signal line to realize the ultrasonic vibration of the impact tool head 6. Fix the electric spindle 7 and the tailstock 8 to the test platform, adjust the height of the electric spindle by adjusting the electric spindle bracket 18 so that its axis is higher than the ultrasonic shot peening strengthening device. Fix the workpiece to the electric spindle 7 through the chuck 20, and then adjust the electric spindle bracket 18 again to lower the electric spindle 7 to the upper surface of the shot peening strengthening device, and cooperate with the tailstock 8 to complete the clamping of the workpiece. Fit the workpiece fixing cover plate 13 that cooperates with the workpiece, and fix it to the impact cover plate 12 through bolts. An ultrasonic shot peening strengthening cavity is formed between the workpiece 14, the workpiece fixing cover plate 13, the impact cover plate 12, the impact outer cover 11 and the impact tool head 6. The shot peening occurs at high speed under the action of the impact tool head 6 and impacts the surface of the workpiece to achieve surface strengthening. Fix the laser galvanometer to the galvanometer bracket 19, and adjust the position of the laser galvanometer through the laser galvanometer fixing bracket 19 so that the laser emitted by the laser galvanometer 15 irradiates the upper surface of the workpiece, and connect the laser galvanometer 15 to the laser generator 17.

[0038] Start the electric spindle 7 to make the sample workpiece 14 rotate. Then turn on the ultrasonic generator 16 to start the ultrasonic shot peening strengthening device. Finally, turn on the laser heating device to laser heat the surface of the sample workpiece 14, and then perform ultrasonic shot peening on the sample workpiece 14 to achieve laser-ultrasonic shot peening composite strengthening.

[0039] The above specific description further details the purpose, technical solution and beneficial effects of the invention. It should be understood that the above is only a specific embodiment of the present invention and is not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A laser-ultrasonic shot peening composite strengthening device, characterized in that: It includes an ultrasonic shot peening device, a laser heating device, a laser-ultrasonic shot peening composite strengthening fixture, and a workpiece fixing fixture; The ultrasonic shot peening device includes an ultrasonic generator, a vibration head, a horn, shot peening, an impact tool head, an impact outer cover, and an impact fixing cover plate; the ultrasonic signal generated by the ultrasonic generator is transmitted to the vibration head through an ultrasonic signal line, causing the vibration head to generate ultrasonic vibration. The horn amplifies the ultrasonic vibration amplitude on the vibration head and transmits it to the impact tool head, driving the impact tool head to generate ultrasonic vibration; the ultrasonic vibration of the impact tool head transmits energy to the shot peening on the impact tool head and drives the shot peening to move at high speed, impacting the workpiece above the impact tool head and achieving ultrasonic shot peening strengthening; The laser heating device includes a laser generator, a laser scanner, and a scanner fixing bracket; the laser scanner is fixed to the test platform through the scanner fixing bracket and acts on the surface of the specimen with the laser generated by the laser generator to achieve the effect of local high-speed heating of the specimen; the scanner fixing bracket can be adjusted in the height direction to control the distance between the laser scanner and the workpiece, thereby controlling the laser heating effect; The laser-ultrasonic shot peening composite strengthening fixture includes an impact outer cover, an impact cover plate, and a workpiece fixing cover plate; the impact outer cover is in clearance fit with the impact tool head and is tightly fitted with the impact cover plate through bolts to form an ultrasonic shot peening strengthening cavity; a through hole is reserved in the middle of the impact cover plate, and the shot peening impacts the surface of the specimen through the reserved through hole in the middle; the workpiece fixing cover plate is in clearance fit with the workpiece and is fixed to the impact cover plate through bolts, and the workpiece can rotate freely within the workpiece fixing cover plate; The workpiece fixing fixture includes an electric spindle, a chuck, a tailstock, and an electric spindle bracket; The electric spindle is fixed to the test platform through the electric spindle bracket, and the rotational movement of the electric spindle is transmitted to the workpiece through the chuck to control the rotational movement of the workpiece; the electric spindle bracket can be adjusted in the height direction to adjust the position of the electric spindle; the tailstock is fixed to the test platform and cooperates with the chuck to fix the tail end of the workpiece to prevent the workpiece from flexing.

2. A laser-ultrasonic shot peening composite strengthening method, which is realized based on the laser-ultrasonic shot peening composite strengthening device according to claim 1, and is characterized in that: Fix the ultrasonic shot peening strengthening device to the test platform through a fixed sleeve, and connect the ultrasonic shot peening strengthening device to the ultrasonic generator through an ultrasonic signal line to achieve the ultrasonic vibration of the impact tool head; fix the electric spindle and the tailstock to the test platform, adjust the height of the electric spindle by adjusting the electric spindle support so that its axis is higher than the ultrasonic shot peening strengthening device; fix the workpiece to the electric spindle through a chuck, and adjust the electric spindle support again to lower the electric spindle to the upper surface of the shot peening strengthening device, and cooperate with the tailstock to complete the clamping of the workpiece; fix the workpiece fixing cover plate that cooperates with each other to the workpiece, and fix it to the impact cover plate through bolts. An ultrasonic shot peening strengthening cavity is formed between the workpiece, the workpiece fixing cover plate, the impact cover plate, the impact outer cover and the impact tool head. The shot peening occurs at high speed under the action of the impact tool head and impacts the surface of the workpiece to achieve surface strengthening; fix the laser galvanometer to the galvanometer support, and adjust the position of the laser galvanometer through the galvanometer support so that the laser emitted by the galvanometer irradiates the upper surface of the workpiece, and connect the laser galvanometer to the laser generator.

3. The laser-ultrasonic shot peening composite strengthening method according to claim 2, wherein: Turn on the electric spindle to make the workpiece rotate, then turn on the ultrasonic generator to start the ultrasonic shot peening strengthening device, and finally turn on the laser heating device to laser heat the surface of the specimen, and then perform ultrasonic shot peening on the specimen to achieve laser-ultrasonic shot peening composite strengthening.

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