Device and method for improving forming morphology and quality of laser cladding layer

Abstract

The invention discloses a device and method for improving the forming morphology and quality of a laser cladding layer, and relates to the technical field of laser cladding, the device comprises a laser cladding head synchronously moving in the axial direction of a shaft part and an auxiliary forming device used for cooling and polishing the shaft part, the shaft part can rotate, and the auxiliary forming device is located on the rear portion of the laser cladding head; the auxiliary forming device comprises an argon quenching part and a polishing part which are sequentially arranged from front to back, the argon quenching part is in clearance fit with the outer surface of the shaft part, and the polishing part is in contact with the surface of the cooled cladding layer; the auxiliary forming device is located at the bottom of the shaft part, and the laser cladding head is located at the top of the shaft part. The auxiliary forming device is arranged behind the laser cladding head, so that the cooling speed in the cooling stage in the laser cladding process is increased, the surface flatness of a cladding layer is improved, the surface appearance and macroscopic mechanical performance of the formed cladding layer are improved, a high-performance laser cladding coating is obtained, and the production efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of laser cladding, and in particular to a device and method for improving the forming morphology and quality of a laser cladding layer. Background Art

[0002] Laser cladding technology is one of the commonly used methods to improve the surface properties of metals, and has been widely used in metal surface strengthening. Previous studies have shown that due to the characteristics of laser heat source, that is, rapid heating and cooling, the prepared laser cladding layer has high strength, hardness and excellent mechanical properties. Moreover, for larger molten pools, although the speed is very fast in the heating stage, its cooling speed is slower during the cooling stage, especially in the middle of the molten pool. The large difference in cooling speed between the middle position of the molten pool and the surrounding area will lead to a large difference in microstructure between the middle position of the molten pool and the surrounding area, showing large residual stress and poor macroscopic properties. For example, in the invention patent with application number 202011567963.1, there is no cooling device around the laser cladding head, and the cooling speed of the middle position of the molten pool cannot be accelerated.

[0003] In addition, the surface of the cladding layer prepared by laser cladding technology is usually low in flatness and high in surface roughness, especially when the rod is used as a plunger, high surface flatness and small surface roughness are required. Usually, surface treatment of the laser cladding layer is two processes completely separated from the laser cladding process. Such an operation process wastes a lot of time and reduces the production efficiency of the laser cladding process. The invention patent with application number 202210852773.7 has a wire wheel grinding head and a laser cleaning processing head on both sides of the laser cladding head. During processing, as the shaft workpiece rotates, the wire wheel grinding head and the laser cleaning processing head respectively grind the previous cladding layer to remove large-particle oxide scale and tiny surface oxides generated by grinding, but this device cannot speed up the cooling rate in the middle of the molten pool.

[0004] Therefore, providing a device and method for improving the forming morphology and quality of the laser cladding layer, accelerating the cooling rate in the cooling stage during the laser cladding process, improving the surface flatness of the cladding layer, and improving the surface morphology and macro-mechanical properties of the cladding layer after laser forming is of great significance for obtaining high-performance laser cladding coatings, improving production efficiency and expanding the application of laser cladding technology. Summary of the invention

[0005] The present invention provides a device and method for improving the forming morphology and quality of a laser cladding layer in order to accelerate the cooling speed in the cooling stage during the laser cladding process, improve the surface flatness of the cladding layer, and improve production efficiency.

[0006] The technical solution of the present invention is: a device for improving the morphology and quality of laser cladding layer, comprising a laser cladding head that moves synchronously along the axial direction of a shaft part and an auxiliary forming device for cooling and polishing the shaft part, the shaft part can rotate, and the auxiliary forming device is located at the rear of the laser cladding head; The auxiliary forming device comprises an argon quenching part and a grinding part which are arranged in sequence from front to back, the argon quenching part is in clearance fit with the outer surface of the shaft part, and the grinding part is in contact with the surface of the cooled cladding layer.

[0007] Preferably, the auxiliary forming device is located at the bottom of the shaft part, and the laser cladding head is located at the top of the shaft part.

[0008] Preferably, the argon quenching part is provided with an arc surface that matches the outer surface of the shaft part, the arc surface is clearance-matched with the outer surface of the shaft part, and its height does not exceed the horizontal mid-axis plane of the shaft part, and a plurality of argon outlets for providing cooling gas are provided at its lowest point; the argon outlet is connected to an argon tank via an argon delivery pipe.

[0009] Preferably, the argon gas delivery pipe is detachably connected to the argon gas outlet via a quick connector.

[0010] Preferably, the grinding portion is an arc-shaped grinding sheet, which is installed at the rear of the arc surface, and its curvature is adapted to the outer surface of the shaft part, and the grinding sheet is in contact with the surface of the cooled cladding layer.

[0011] Preferably, it further comprises a workbench, a chuck and an ejector pin, wherein the chuck and the ejector pin are both arranged on the workbench and are arranged opposite to each other; one end of the shaft part is clamped on the chuck, and the other end is rotatably connected to the ejector pin.

[0012] Preferably, an axially movable slide is provided between the chuck and the ejector pin, the auxiliary molding device is fixedly mounted on the slide, and the slide is connected to a stepping motor via a screw transmission mechanism.

[0013] Preferably, it further comprises a mechanical arm, an optical fiber cable and a laser generator, wherein the laser cladding head is installed at the working end of the mechanical arm and is connected to the laser generator via the optical fiber cable.

[0014] A method for using a device for improving the morphology and quality of a laser cladding layer comprises the following steps: S1 laser cladding: Fix the shaft parts on the chuck, start the chuck to drive the shaft parts to rotate, start the robot arm to drive the laser cladding head to move along the axial direction of the shaft parts, and realize laser cladding of the shaft parts; S2 Cooling: After the laser cladding head has clad several circles on the shaft parts, the argon tank is opened, and the cladding layer is quickly cooled by the argon gas flowing out of the argon outlet; S3 grinding: Along the direction of laser cladding, a grinding sheet is provided at the rear of the argon outlet. The grinding sheet is fed along the cladding direction and contacts the cladding layer, and finally a relatively flat cladding layer morphology is obtained.

[0015] Compared with the prior art, the present invention has the following advantages: As the shaft parts rotate, the argon quenching section in the auxiliary forming device can force convection on the molten pool, transition zone and heat-affected zone of the cladding layer after forming, accelerate the cooling speed in the cooling stage, obtain a microstructure that helps to improve the macroscopic mechanical properties, improve the macroscopic mechanical properties after forming, and improve the efficiency of the laser cladding process; in addition, when the cooled cladding layer is transferred to the grinding section, the grinding section grinds the uneven surface of the cladding layer into a smooth surface of the cladding layer. Compared with the method of grinding the cladding layer separately after the laser cladding is completed, this device integrates rapid cooling and grinding into one, improves the integration of the device, saves the time of subsequent surface treatment, and improves production efficiency. The argon quenching section is provided with an arc surface that is compatible with the shaft parts, and the argon outlet is set at the lowest end of the arc surface. Under the guidance of the arc surface, the argon gas can cool the part of the shaft parts that is not directly above the argon outlet, expands the cooling area, and improves the effect of rapid cooling. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 It is a structural schematic diagram of the auxiliary molding device; Figure 3 It is a schematic diagram of the arrangement of the laser cladding head and the auxiliary forming device of the present invention; Figure 4 Schematic diagram of the morphology of the cladding layer before grinding; Figure 5 Schematic diagram of the morphology of the cladding layer after grinding; Figure 6 It is a schematic diagram of the motion principle of the auxiliary forming device; Figure 7 It is a temperature rise and cooling curve diagram of the cladding layer of the present invention.

[0017] In the figure: 1. shaft parts, 2. laser cladding head, 3. auxiliary forming device, 4. curved surface, 5. argon outlet, 6. argon tank, 7. argon delivery pipe, 8. quick connector, 9. three-way connector, 10. grinding sheet, 11. chuck, 12. ejector pin, 13. claw, 14. workbench, 15. slide, 16. transmission screw, 17. stepper motor, 18. robot arm, 19. cladding layer morphology before grinding, 20. cladding layer morphology after grinding, 21. molten pool cooling temperature curve, 22. transition zone cooling temperature curve, 23. heat affected zone cooling temperature curve. DETAILED DESCRIPTION

[0018] The present invention is further described below with reference to the accompanying drawings and embodiments. Embodiment 1

[0019] Reference Figure 1-3 As shown, a device for improving the morphology and quality of laser cladding layer forming includes a laser cladding head 2 that moves synchronously along the axial direction of a shaft part 1 and an auxiliary forming device 3 for cooling and polishing the shaft part 1. The shaft part 1 can rotate, and the auxiliary forming device 3 is located at the rear of the laser cladding head 2; The auxiliary forming device 3 includes an argon quenching part and a grinding part arranged from front to back. The axial distance between the argon quenching part and the grinding part is ≥2n, n is the width of a laser cladding layer, the argon quenching part is in clearance with the outer surface of the shaft part 1, and the grinding part is in contact with the surface of the cooled cladding layer.

[0020] As the shaft part 1 rotates, the argon quenching part in the auxiliary forming device 3 can force convection on the molten pool, transition zone and heat-affected zone of the formed cladding layer, accelerate the cooling rate in the cooling stage, and obtain a microstructure that helps to improve the macroscopic mechanical properties. This method has a more significant improvement effect on the situation where the molten pool size is large during the laser cladding process, and can improve the efficiency of the laser cladding process. The temperature change trend of the cladding layer during the production process is shown in the figure. Figure 7 As shown; in addition, when the cooled cladding layer is transferred to the grinding part, the grinding part grinds the uneven surface of the cladding layer into a smooth surface of the cladding layer. Compared with the method of grinding the cladding layer separately after the laser cladding is completed, the present device integrates rapid cooling and grinding into one, improves the integration of the device, saves the time of subsequent surface treatment, and improves the production efficiency; furthermore, in the axial direction, the laser cladding head 2 is located in front of the argon quenching part, the argon quenching part is located in front of the grinding part, and the distance between the argon quenching part and the grinding part is ≥2n, that is, when the grinding part grinds the cladding layer, the number of passes clad by the laser cladding head 2 on the shaft part 1 exceeds two, that is, during grinding, the laser cladding head 2 has completed the overlap between adjacent cladding layers on the shaft part 1, and the fine particles generated by grinding will not affect the quality of laser cladding. Embodiment 2

[0021] As a preferred embodiment of the present invention, this embodiment optimizes the structure of the device based on the first embodiment, specifically: In this embodiment, the auxiliary forming device 3 is located at the bottom of the shaft part 1, and the laser cladding head 2 is located at the top of the shaft part 1. The argon quenching part is provided with an arc surface 4 adapted to the outer surface of the shaft part 1, and the arc surface 4 is gap-matched with the outer surface of the shaft part 1, and its height does not exceed the horizontal central axis of the shaft part 1. The lowest point is provided with a plurality of argon outlets 5 for providing cooling gas; the argon outlet 5 is connected to an argon tank 6 through an argon delivery pipe 7.

[0022] Under the guidance of the arc surface 4, the argon gas can flow upward along the arc surface 4, expanding the cooling area of ​​the argon gas on the shaft parts 1 and improving the cooling effect; in order to prevent the argon gas flowing out from the gap between the arc surface 4 and the shaft parts 1 from blowing obliquely toward the molten pool and affecting the welding quality, the height of the arc surface 4 in this embodiment does not exceed the horizontal mid-axis plane of the shaft parts 1. The argon tank 6 is connected to the argon gas delivery pipe 7, and the argon gas delivery pipe 7 is detachably connected to the argon gas outlet 5 through a quick connector 8, which improves the convenience of using the device. As a preferred embodiment of the present invention, three argon gas outlets 5 are provided at the lowest point of the arc surface 4, and the argon gas outlet 5 is connected to the quick connector 8 through a three-way connector 9. Of course, the number of argon gas outlets 5 is not limited to three, and can be reasonably set according to actual needs. Embodiment 3

[0023] As a preferred embodiment of the present invention, this embodiment optimizes the grinding part on the basis of the second embodiment, specifically: In this embodiment, the grinding portion is an arc-shaped grinding sheet 10, which is installed at the rear of the arc surface 4, and its curvature is adapted to the outer surface of the shaft part 1, and the grinding sheet 10 is in contact with the surface of the cooled cladding layer.

[0024] In more detail, the grinding sheet 10 can be detachably mounted on the rear portion of the curved surface 4 so as to facilitate timely replacement of the grinding sheet 10 . Embodiment 4

[0025] As a preferred embodiment of the present invention, this embodiment further optimizes the structure of the device on the basis of the third embodiment, specifically: This embodiment also includes a workbench 14, a chuck 11 and an ejector pin 12. The chuck 11 and the ejector pin 12 are both arranged on the workbench 14 and are arranged opposite to each other. One end of the shaft part 1 is clamped on the chuck 11, and the other end is rotatably connected to the ejector pin 12.

[0026] The chuck 11 has a plurality of claws 13, which are used to clamp and fix the shaft parts 1. The ejector pin 12 is used to ensure the coaxiality of the clamped shaft parts 1 to avoid processing errors caused by different axes. The type of chuck 11 is selected according to needs when in use. The chuck 11 in this embodiment is a three-jaw chuck 11. Embodiment 5

[0027] As a preferred embodiment of the present invention, this embodiment further optimizes the structure of the device on the basis of the fourth embodiment, specifically: Reference Figure 6 As shown, in this embodiment, an axially movable slide 15 is provided between the chuck 11 and the ejector pin 12, the auxiliary molding device 3 is fixedly mounted on the slide 15, and the slide 15 is connected to a stepper motor 17 through a screw transmission mechanism. Specifically, the slide 15 is sleeved on a transmission screw 16, one end of which is connected to the stepper motor 17, and the rotation of the transmission screw 16 drives the slide 15 to move forward and backward.

[0028] It also includes a mechanical arm 18, an optical fiber cable and a laser generator. The laser cladding head 2 is installed at the working end of the mechanical arm 18 and is connected to the laser generator through an optical fiber cable.

[0029] The stepper motor 17 and the robotic arm 18 are respectively connected to the control mechanism signal for adjusting the movement speed of the stepper motor 17 and the robotic arm 18, so that the auxiliary forming device 3 and the laser cladding head 2 can move synchronously, ensuring that the relative position of the auxiliary forming device 3 and the laser cladding head 2 will not change during the working process, so as not to affect the quality of laser cladding.

[0030] The present invention also provides a method for using the device for improving the forming morphology and quality of the laser cladding layer, comprising the following steps: S1 laser cladding: fix the shaft part 1 on the chuck 11, start the chuck 11 to drive the shaft part 1 to rotate; fix the laser cladding head 2 on the mechanical arm 18, start the mechanical arm 18 to drive the laser cladding head 2 to move axially along the shaft part 1, and realize laser cladding of the shaft part 1; S2 Cooling: After the laser cladding head 2 clads the shaft part 1 for several turns, the argon tank 6 is opened, and the argon gas flowing out of the argon outlet 5 is used to quickly cool the cladding layer; S3 grinding: Along the direction of laser cladding, a grinding sheet 10 is provided at the rear of the argon outlet 5. The grinding sheet 10 is fed along the cladding direction and contacts the cladding layer, and finally a relatively flat cladding layer morphology is obtained; the cladding layer morphology 19 before grinding and the cladding layer morphology 20 after grinding are shown in FIG. Figure 4-5 shown.

[0031] The present invention is not limited to the above-mentioned embodiments. Various changes can be made within the knowledge scope of those skilled in the art without departing from the spirit of the present invention. The changed contents still fall within the protection scope of the present invention.

Claims

1. A device for improving the morphology and quality of laser cladding layer, characterized by: It includes a laser cladding head that moves synchronously along the axial direction of the shaft part and an auxiliary forming device for cooling and polishing the shaft part. The shaft part can rotate on its own, and the auxiliary forming device is located at the rear of the laser cladding head; The auxiliary forming device comprises an argon quenching part and a grinding part which are arranged in sequence from front to back, the argon quenching part is in clearance fit with the outer surface of the shaft part, and the grinding part is in contact with the surface of the cooled cladding layer.

2. The device for improving the morphology and quality of laser cladding layer according to claim 1, characterized in that: The auxiliary forming device is located at the bottom of the shaft part, and the laser cladding head is located at the top of the shaft part.

3. The device for improving the morphology and quality of laser cladding layer according to claim 2, characterized in that: The argon quenching part is provided with an arc surface that matches the outer surface of the shaft part. The arc surface is clearance-matched with the outer surface of the shaft part, and its height does not exceed the horizontal mid-axis plane of the shaft part. A plurality of argon outlets for providing cooling gas are provided at its lowest point; the argon outlet is connected to an argon tank via an argon delivery pipe.

4. The device for improving the morphology and quality of laser cladding layer according to claim 3, characterized in that: The argon gas delivery pipe is detachably connected to the argon gas outlet via a quick connector.

5. The device for improving the morphology and quality of laser cladding layer according to claim 3, characterized in that: The grinding part is an arc-shaped grinding sheet, which is installed at the rear of the arc surface, and its curvature is adapted to the outer surface of the shaft part, and the grinding sheet is in contact with the surface of the cooled cladding layer.

6. The device for improving the morphology and quality of laser cladding layer according to claim 1, characterized in that: It also includes a workbench, a chuck and an ejector pin. The chuck and the ejector pin are both arranged on the workbench and are arranged opposite to each other. One end of the shaft part is clamped on the chuck, and the other end is rotatably connected to the ejector pin.

7. The device for improving the morphology and quality of laser cladding layer according to claim 6, characterized in that: An axially movable slide is provided between the chuck and the ejector pin, the auxiliary molding device is fixedly mounted on the slide, and the slide is connected to a stepping motor via a screw transmission mechanism.

8. The device for improving the morphology and quality of laser cladding layer according to claim 1, characterized in that: It also includes a mechanical arm, an optical fiber cable and a laser generator. The laser cladding head is installed at the working end of the mechanical arm and is connected to the laser generator through the optical fiber cable.

9. A method for using a device for improving the morphology and quality of laser cladding layer, characterized in that: The following steps are involved: S1 laser cladding: Fix the shaft parts on the chuck, start the chuck to drive the shaft parts to rotate, start the robot arm to drive the laser cladding head to move along the axial direction of the shaft parts, and realize laser cladding of the shaft parts; S2 Cooling: After the laser cladding head has clad several circles on the shaft parts, the argon tank is opened, and the cladding layer is quickly cooled by the argon gas flowing out of the argon outlet; S3 grinding: Along the direction of laser cladding, a grinding sheet is provided at the rear of the argon outlet. The grinding sheet is fed along the cladding direction and contacts the cladding layer, and finally a relatively flat cladding layer morphology is obtained.

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