An apparatus and method for improving the forming appearance and quality of a laser cladding layer

Abstract

The application discloses a device and method for improving forming appearance and quality of a laser cladding layer, and relates to the technical field of laser cladding, comprising a laser cladding head moving synchronously along the axial direction of an axial part and an auxiliary forming device for cooling and polishing the axial part, the axial 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 polishing part arranged in sequence from front to back, the argon quenching part is in gap fit with the outer surface of the axial 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 axial part, and the laser cladding head is located at the top of the axial part; by arranging the auxiliary forming device behind the laser cladding head, the cooling speed in the cooling stage of the laser cladding process is accelerated, the surface flatness of the cladding layer is improved, the surface appearance and macro mechanical properties 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 present application relates to the technical field of laser cladding, in particular to a device and method for improving the forming appearance and quality of laser cladding layer. BACKGROUND

[0002] Laser cladding technology is one of the common methods to improve the performance of metal surface and has been widely used in metal surface strengthening. Previous studies have shown that due to the characteristics of laser heat source, i.e. fast cooling, the prepared laser cladding layer has high strength, hardness and excellent mechanical properties. Moreover, although the speed is very fast in the heating stage for the large-sized molten pool, the cooling speed is slow in the cooling stage, especially at the middle position of the molten pool. The large difference in cooling speed between the middle position and the surrounding area of the molten pool will lead to the formation of different microstructures at the middle position and the surrounding area of the molten pool, resulting in large residual stress and poor macroscopic performance. For example, the patent application No. 202011567963.1 does not provide a cooling device around the laser cladding head, which cannot accelerate the cooling speed at the middle position of the molten pool.

[0003] In addition, the surface of the cladding layer prepared by laser cladding technology usually has low flatness and large surface roughness, especially when the rod is used as a plunger, which requires high surface flatness and small surface roughness. Usually, the surface treatment of the laser cladding layer is a completely separate process from the laser cladding process, which wastes a lot of time and reduces the production efficiency of the laser cladding process. The patent application No. 202210852773.7 provides a steel wire wheel polishing head and a laser cleaning processing head on both sides of the laser cladding head. During processing, the steel wire wheel polishing head and the laser cleaning processing head polish the cladding layer of the previous pass respectively to remove the surface large particle oxide scale and the surface small oxide generated by polishing, but this device also cannot accelerate the cooling speed at the middle position of the molten pool.

[0004] Therefore, it is of great significance to provide a device and method for improving the forming appearance and quality of laser cladding layer, accelerating the cooling speed in the cooling stage of the laser cladding process, improving the surface flatness of the cladding layer, improving the surface appearance and macroscopic mechanical properties of the laser formed cladding layer, obtaining high-performance laser cladding coating, improving production efficiency and expanding the application of laser cladding technology. SUMMARY

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

[0006] The technical scheme of the present application is: a device for improving the forming appearance and quality of a laser cladding layer, comprising a laser cladding head moving synchronously along the axial direction of an axial part and an auxiliary forming device for cooling and polishing the axial part, the axial part being capable of rotating, and the auxiliary forming device being located at the rear of the laser cladding head.

[0007] The auxiliary forming device comprises an argon quenching part and a polishing part arranged in sequence from front to rear, the argon quenching part being in clearance fit with the outer surface of the axial part, and the polishing part being in contact with the surface of the cooled cladding layer.

[0008] Preferably, the auxiliary forming device is located at the bottom of the axial part, and the laser cladding head is located at the top of the axial part.

[0009] Preferably, the argon quenching part is provided with a curved surface matched with the outer surface of the axial part, the curved surface being in clearance fit with the outer surface of the axial part and having a height not exceeding the horizontal central axis surface of the axial part, and the lowest part of the curved surface being provided with a plurality of argon outlets for providing cooling gas; the argon outlets are connected with an argon tank through an argon delivery pipe.

[0010] Preferably, the argon delivery pipe is detachably connected with the argon outlets through a quick connector.

[0011] Preferably, the polishing part is an arc-shaped polishing sheet, the polishing sheet being installed at the rear of the curved surface, the curvature of the polishing sheet being matched with the outer surface of the axial part, and the polishing sheet being in contact with the surface of the cooled cladding layer.

[0012] Preferably, the device further comprises a workbench, a chuck and a center pin, the chuck and the center pin being arranged on the workbench and opposite to each other, one end of the axial part being clamped on the chuck, and the other end being rotatably connected with the center pin.

[0013] Preferably, an axially movable sliding table is arranged between the chuck and the center pin, the auxiliary forming device being fixedly installed on the sliding table, and the sliding table being connected with a stepping motor through a lead screw transmission mechanism.

[0014] Preferably, the device further comprises a mechanical arm, an optical fiber cable and a laser generator, the laser cladding head being installed at the working end of the mechanical arm and being connected with the laser generator through the optical fiber cable.

[0015] A use method of a device for improving the forming appearance and quality of a laser cladding layer, comprising the following steps:

[0016] S1 laser cladding: fixing the axial part on the chuck, starting the chuck to drive the axial part to rotate, and starting the mechanical arm to drive the laser cladding head to move along the axial direction of the axial part to realize laser cladding of the axial part;

[0017] S2 cooling: after the laser cladding head clads several circles on the shaft part, open the argon tank, and the argon flowing out of the argon outlet is used to rapidly cool the cladding layer;

[0018] S3 polishing: the rear part of the argon outlet is provided with a polishing piece along the laser cladding direction, the polishing piece is fed along the cladding direction and contacts the cladding layer, and finally a relatively flat cladding layer morphology is obtained.

[0019] Compared with the prior art, the present application has the following advantages:

[0020] With the rotation of the shaft part, the argon quenching part in the auxiliary forming device can force convection on the formed cladding layer molten pool, transition zone and heat affected zone, accelerate the cooling speed in the cooling stage, obtain the microstructure that is helpful to improve the macro mechanical properties, improve the macro mechanical properties after forming, and improve the efficiency of the laser cladding process; in addition, when the cooled cladding layer is transferred to the polishing part, the polishing part polishes the uneven cladding layer morphology into a flat cladding layer morphology, compared with the way of polishing the cladding layer separately after the laser cladding is completed, the present device integrates rapid cooling and polishing, improves the integration of the device, saves the time of subsequent surface treatment, and improves the production efficiency. The arc surface matched with the shaft part is arranged on the argon quenching part, and the argon outlet is arranged at the lowest end of the arc surface, under the guidance of the arc surface, the argon can cool the part of the shaft part which is not directly above the argon outlet, expand the cooling area, and improve the effect of rapid cooling. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 It is a schematic diagram of the overall structure of the present application;

[0022] Figure 2 It is a schematic diagram of the structure of the auxiliary forming device;

[0023] Figure 3 It is a schematic diagram of the arrangement of the laser cladding head and the auxiliary forming device of the present application;

[0024] Figure 4 It is a schematic diagram of the cladding layer morphology before polishing;

[0025] Figure 5 It is a schematic diagram of the cladding layer morphology after polishing;

[0026] Figure 6 It is a schematic diagram of the motion principle of the auxiliary forming device;

[0027] Figure 7 It is a cladding layer temperature rising and cooling curve diagram of the present application.

[0028] In the figure: 1, shaft parts, 2, laser cladding head, 3, auxiliary forming device, 4, camber, 5, argon outlet, 6, argon tank, 7, argon delivery tube, 8, quick connector, 9, tee joint, 10, polishing piece, 11, chuck, 12, center pin, 13, clamping jaw, 14, worktable, 15, sliding table, 16, transmission screw, 17, stepper motor, 18, mechanical arm, 19, cladding layer appearance before polishing, 20, cladding layer appearance after polishing, 21, cooling temperature curve of molten pool, 22, cooling temperature curve of transition zone, 23, cooling temperature curve of heat affected zone. DETAILED DESCRIPTION

[0029] The application is further illustrated below in conjunction with the accompanying drawings and examples. Example 1

[0030] Referring to Figures 1-3 the figure, an apparatus for improving the forming appearance and quality of laser cladding layer includes a laser cladding head 2 moving synchronously along the axial direction of shaft parts 1 and an auxiliary forming device 3 for cooling and polishing the shaft parts 1, the shaft parts 1 can rotate, and the auxiliary forming device 3 is located at the rear of the laser cladding head 2.

[0031] The auxiliary forming device 3 includes an argon quenching part and a polishing part arranged in sequence from front to back, the axial distance between the argon quenching part and the polishing part is ≥2n, n is the width of a laser cladding layer, the argon quenching part is in clearance fit with the outer surface of the shaft parts 1, and the polishing part is in contact with the surface of the cooled cladding layer.

[0032] With the rotation of the shaft parts 1, 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 speed in the cooling stage, and obtain microstructure conducive to improving macroscopic mechanical properties, the method is more effective for the improvement of the case where the molten pool size is large in the laser cladding process, and can improve the efficiency of the laser cladding process, the temperature change trend of the cladding layer in the production process is as shown in Figure 7 the figure; in addition, when the cooled cladding layer is transferred to the polishing part, the polishing part polishes the uneven cladding layer appearance into a flat cladding layer appearance, compared with the way of polishing the cladding layer separately after the laser cladding is completed, the apparatus integrates the rapid cooling and polishing into one, improves the integration of the apparatus, saves the time of subsequent surface treatment, and improves the production efficiency; furthermore, in the axial direction, the laser cladding head 2 is located at the front of the argon quenching part, the argon quenching part is located at the front of the polishing part, and the distance between the argon quenching part and the polishing part is ≥2n, that is, when the polishing part polishes the cladding layer, the number of cladding layers on the shaft parts 1 by the laser cladding head 2 exceeds two, that is, when polishing, the laser cladding head 2 has completed the lap joint between adjacent cladding layers on the shaft parts 1, and the fine particulate matter generated by polishing will not affect the quality of the laser cladding. Embodiment Two

[0033] As a preferred embodiment of the present application, the structure of the device is optimized based on Embodiment One, specifically:

[0034] 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 a curved surface 4 matched with the outer surface of the shaft part 1. The curved surface 4 is in clearance fit with the outer surface of the shaft part 1, and its height does not exceed the horizontal central axis surface of the shaft part 1. The lowest part of the curved surface 4 is provided with a plurality of argon outlets 5 for providing cooling gas. The argon outlets 5 are connected with an argon tank 6 through an argon delivery pipe 7.

[0035] Under the guidance of the curved surface 4, the argon can flow upwards along the curved surface 4, expanding the cooling area of the argon on the shaft part 1 and improving the cooling effect. In order to avoid the argon flowing out of the gap between the curved surface 4 and the shaft part 1 from being inclined to blow to the molten pool, affecting the welding quality, the height of the curved surface 4 in this embodiment does not exceed the horizontal central axis surface of the shaft part 1. The argon tank 6 is connected with the argon delivery pipe 7, and the argon delivery pipe 7 is detachably connected with the argon outlet 5 through a quick connector 8, improving the use convenience of the device. As a preferred embodiment of the present application, the lowest part of the curved surface 4 is provided with three argon outlets 5, and the argon outlets 5 are connected with the quick connector 8 through a tee joint 9. Of course, the number of the argon outlets 5 is not limited to three, and can be reasonably set according to actual needs. Embodiment Three

[0036] As a preferred embodiment of the present application, the polishing part is optimized and set based on Embodiment Two, specifically:

[0037] In this embodiment, the polishing part is an arc-shaped polishing piece 10, which is installed at the rear of the curved surface 4, and its arc is matched with the outer surface of the shaft part 1, and the polishing piece 10 is in contact with the surface of the cooled cladding layer.

[0038] More specifically, the polishing piece 10 is detachably installed at the rear of the curved surface 4, so as to replace the polishing piece 10 in time. Embodiment Four

[0039] As a preferred embodiment of the present application, the structure of the device is further optimized based on Embodiment Three, specifically:

[0040] This embodiment also includes a workbench 14, a chuck 11 and a top pin 12. The chuck 11 and the top pin 12 are both arranged on the workbench 14, and are oppositely arranged. One end of the shaft part 1 is clamped on the chuck 11, and the other end is rotationally connected with the top pin 12.

[0041] The chuck 11 has several clamping jaws 13, and the clamping and fixing of the shaft part 1 are realized by the clamping jaws 13, and the center pin 12 is used to ensure the coaxiality of the clamped shaft part 1, so as to avoid the machining error caused by the misalignment, and the type of the chuck 11 is selected according to the requirements in use, and the chuck 11 of the embodiment is a three-jaw chuck 11. Embodiment five

[0042] As a preferred embodiment of the present application, the structure of the device is further optimized on the basis of embodiment four, in particular:

[0043] Referring to Figure 6 In the embodiment, the chuck 11 and the center pin 12 are provided with an axially movable sliding table 15, the auxiliary forming device 3 is fixedly installed on the sliding table 15, and the sliding table 15 is connected with a stepping motor 17 through a lead screw transmission mechanism. Specifically, the sliding table 15 is sleeved on the transmission lead screw 16, one end of the transmission lead screw 16 is connected with the stepping motor 17, and the transmission lead screw 16 drives the sliding table 15 to move forward and backward through rotation.

[0044] Further comprising a mechanical arm 18, an optical fiber cable and a laser generator, the laser cladding head 2 is installed on the working end of the mechanical arm 18, and is connected with the laser generator through the optical fiber cable.

[0045] The stepping motor 17 and the mechanical arm 18 are respectively connected with a control mechanism signal for regulating the movement speed of the stepping motor 17 and the mechanical arm 18, so that the auxiliary forming device 3 and the laser cladding head 2 can move synchronously, and the relative position of the auxiliary forming device 3 and the laser cladding head 2 in the working process is ensured not to change, so as to avoid affecting the quality of laser cladding.

[0046] The present application also provides a use method of the device for improving the forming appearance and quality of the laser cladding layer, comprising the following steps:

[0047] S1 laser cladding: fixing the shaft part 1 on the chuck 11, starting the chuck 11 to drive the shaft part 1 to rotate; fixing the laser cladding head 2 on the mechanical arm 18, starting the mechanical arm 18 to drive the laser cladding head 2 to move along the shaft part 1 in the axial direction, and realizing the laser cladding of the shaft part 1;

[0048] S2 cooling: after the laser cladding head 2 clads several layers on the shaft part 1, opening the argon tank 6, and rapidly cooling the cladding layer through the argon flowing out of the argon outlet 5;

[0049] S3 polishing: the rear part of the argon outlet 5 is provided with a polishing piece 10 along the direction of laser cladding, the polishing piece 10 feeds along the cladding direction and contacts with the cladding layer, and finally the relatively flat cladding layer appearance is obtained; the cladding layer appearance 19 before polishing and the cladding layer appearance 20 after polishing are shown in Figures 4-5 .

[0050] The present application is not limited to the above-described embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the spirit of the present application, and the changed contents still belong to the protection scope of the present application.

Claims

1. An apparatus for improving the morphology and quality of laser cladding layers, characterized in that: The application relates to a laser cladding head and an auxiliary forming device for cooling and polishing a shaft part, wherein the shaft part can rotate around an axis, and the auxiliary forming device is arranged behind the laser cladding head. The auxiliary forming device comprises an argon quenching part and a polishing part 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 polishing part is in contact with the surface of the cooled cladding layer. The argon quenching part is provided with a curved surface matched with the outer surface of the shaft part, the curved surface is in clearance fit with the outer surface of the shaft part, the height of the curved surface is not higher than the horizontal central surface of the shaft part, the lowest part of the curved surface is provided with a plurality of argon outlets for providing cooling gas, and the argon outlets are connected with an argon tank through an argon delivery pipe. The polishing part is an arc-shaped polishing sheet, the polishing sheet is arranged at the rear part of the curved surface, the curvature of the polishing sheet is matched with the outer surface of the shaft part, and the polishing sheet is in contact with the surface of the cooled cladding layer.

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

3. The device for improving the forming morphology and quality of a laser cladding layer according to claim 1, characterized in that: The argon delivery pipe is detachably connected with the argon outlets through a quick connector.

4. The device for improving the forming morphology and quality of a laser cladding layer according to claim 1, characterized in that: The application further comprises a workbench, a chuck and a top pin, the chuck and the top pin are arranged on the workbench and oppositely arranged, one end of the shaft part is clamped on the chuck, and the other end is rotationally connected with the top pin.

5. The device for improving the forming morphology and quality of a laser cladding layer according to claim 4, characterized in that: A sliding table moving in the axial direction is arranged between the chuck and the top pin, the auxiliary forming device is fixedly arranged on the sliding table, and the sliding table is connected with a stepping motor through a lead screw transmission mechanism.

6. The device for improving the forming morphology and quality of a laser cladding layer according to claim 1, characterized in that: The application further comprises a mechanical arm, an optical fiber cable and a laser generator, the laser cladding head is arranged at the working end of the mechanical arm and connected with the laser generator through the optical fiber cable.

7. A method of using the device for improving the forming morphology and quality of a laser cladding layer according to any one of claims 1-6, characterized in that, The application comprises the following steps: S1 laser cladding: the shaft part is fixed on the chuck, the chuck is started to drive the shaft part to rotate, the mechanical arm is started to drive the laser cladding head to move in the axial direction of the shaft part, and laser cladding of the shaft part is realized; S2 cooling: after the laser cladding head clads several layers on the shaft part, the argon tank is started to rapidly cool the cladding layer through the argon gas flowing out of the argon outlets; S3 polishing: the rear part of the argon outlet is provided with a polishing sheet in the cladding direction, the polishing sheet is fed along the cladding direction and in contact with the cladding layer, and finally a relatively flat cladding layer is obtained.

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