Ultrahigh-speed laser cladding method and system
By adopting the ultra-high-speed laser cladding method in laser cladding technology and using dual-energy laser design, the problems of thermal deformation of the substrate and uneven cladding layer in the prior art are solved, and efficient and flat cladding layer formation is achieved, reducing maintenance costs.
Patent Information
- Application Number
- CN202411808604.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-10
- Publication Date
- 2025-03-14
AI Technical Summary
When existing laser cladding technology protects expensive metal parts, it causes thermal deformation of the substrate and uneven surface of the cladding layer, and requires secondary processing, which increases maintenance costs.
The ultra-high-speed laser cladding method is adopted to melt the self-melting alloy powder by the first energy cladding laser, and use gravity and powder-carrying airflow to form a molten pool on the surface of the substrate; at the same time, the second energy cladding laser acts on the surface of the substrate outside the melting pool to melt the surface to achieve efficient cladding.
It reduces the thermal damage to the substrate by laser, improves the flatness and density of the cladding layer, reduces the secondary processing requirements, and reduces maintenance costs.
Smart Images
Figure CN119615148A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to laser processing technology, and more particularly to an ultra-high-speed laser cladding method and system. Background Art
[0002] For the protection of expensive metal parts (hereinafter referred to as the substrate), electroplating (chrome plating), painting and other methods are generally used to protect the metal surface, but the protective layer is thin and it is easy to fall off or be torn after a period of time, which will cause corrosion and rust of the parts, bringing great maintenance costs to users. Laser cladding technology can replace part of the electroplating work, but it also has certain disadvantages. For example, in the early stage of cladding, the surface of the substrate needs to be cleaned manually, and in the process of laser cladding on the substrate, the melting point of the laser on the alloy powder is consistent with the position of the molten pool, so that the substrate will absorb part of the laser energy, resulting in low utilization of laser energy. Therefore, more energy is needed to act on the alloy powder to achieve the cladding effect. However, because it requires more laser energy, more laser energy is input and acts on the substrate, which is easy to have a greater thermal impact on the substrate, causing the body to easily produce thermal deformation, affecting product quality. In addition, the surface flatness of the coating after cladding is not high, and the fluctuations are large, so the substrate coating needs to be rough-turned and fine-ground later. Summary of the invention
[0003] The technical problem to be solved by the present invention is to provide an ultra-high-speed laser cladding method and system in view of the deficiencies in the prior art, which reduces the damage caused to the substrate, and the processed cladding layer has high flatness and density, and does not require secondary processing.
[0004] The ultra-high-speed laser cladding method of the present invention comprises the following steps:
[0005] Step 1: Load the substrate to the set cladding processing area;
[0006] Step 2: performing surface cleaning and preheating treatment on the substrate;
[0007] Step 3, after positioning the substrate surface after step 2, the substrate is driven to move according to the set cladding process, and step 4 is performed at the same time;
[0008] Step 4: self-fluxing alloy powder is loaded above the positioned surface of the substrate, and a first energy cladding laser is used to act on the self-fluxing alloy powder to make the self-fluxing alloy powder molten. The molten self-fluxing alloy powder falls under the action of gravity and powder-carrying airflow to form a molten pool on the surface of the substrate; at the same time, a second energy cladding laser is used to act on the substrate surface outside the molten pool to melt the substrate surface of the substrate;
[0009] Step 5: When the surface of the substrate on which the cladding layer is to be processed is processed, the quality of the cladding layer on the surface of the substrate is inspected to complete the processing.
[0010] Preferably, the laser energy density of the first energy cladding laser is 8-9.5 times the laser energy density of the second energy cladding laser.
[0011] Preferably, the sum of the laser energy density of the first energy cladding laser and the second energy cladding laser is the output laser energy density of the laser cladding head.
[0012] Preferably, the output laser energy density of the laser cladding head is 2 kW / cm 2 -3kW / cm 2 .
[0013] Preferably, the spot diameter of the first energy cladding laser is less than 1 mm.
[0014] Preferably, the cladding process is 0.5m 2 / h-2m 2 / h.
[0015] Preferably, the second energy cladding laser is provided with two laser beams, both of which are irradiated obliquely on the molten pool, and the laser beams are also irradiated on the edge of the molten pool on the side opposite to the laser beam.
[0016] Preferably, the angle between the second energy cladding laser and the first energy cladding laser is 15°-30°.
[0017] An ultra-high-speed laser cladding system using the ultra-high-speed laser cladding method comprises:
[0018] Visual monitoring equipment, used to monitor whether the substrate is loaded into the set cladding processing area, and to perform quality inspection on the cladding layer on the surface of the substrate;
[0019] A laser cleaning device, used to perform step 2 of the ultra-high-speed laser cladding method;
[0020] The laser cladding head is used to perform step 4 of the ultra-high-speed laser cladding method.
[0021] Preferably, the system further comprises a bracket, and the visual monitoring equipment, the laser cleaning device and the laser cladding head are all mounted on the bracket, and a manipulator connecting flange is also mounted on the bracket.
[0022] Beneficial Effects
[0023] The advantages of the present invention are: through the redistribution of laser energy, the design of the first energy cladding laser and the second energy cladding laser is adopted to concentrate the laser energy on the self-fluxing alloy powder to form a molten state, thereby reducing the thermal damage caused by the laser to the substrate and protecting the substrate. The second energy cladding laser with a lower energy density is used to melt the surface of the substrate material at the edge of the molten pool, which not only reduces the loss caused to the substrate, but also facilitates the firm bonding of the self-fluxing alloy powder and the substrate, so that the processed cladding layer has high flatness and density, and no secondary machining is required later, which helps to maintain the integrity and performance of the workpiece. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 Schematic diagram of the traditional laser cladding method;
[0025] Figure 2 It is a schematic diagram of the laser cladding method of the present invention;
[0026] Figure 3 A comparison of the morphology of the surface of AISI431 stainless steel coating prepared by conventional laser cladding and laser cladding of the present invention;
[0027] Figure 4 It is a schematic diagram of the three-dimensional structure of the ultra-high-speed laser cladding system of the present invention.
[0028] Among them: 1-laser beam, 2-self-fluxing alloy powder, 3-molten pool, 4-cladding layer, 5-substrate, 6-first energy cladding laser, 7-second energy cladding laser, 8-visual monitoring equipment, 9-laser cleaning device, 10-laser cladding head, 11-bracket, 12-manipulator connecting flange. DETAILED DESCRIPTION
[0029] The present invention will be further described below in conjunction with the embodiments, but it does not constitute any limitation to the present invention. Any limited number of modifications made by anyone within the scope of the claims of the present invention are still within the scope of the claims of the present invention.
[0030] Example 1
[0031] like Figure 2 As shown, an ultra-high speed laser cladding method of the present invention comprises the following steps:
[0032] Step 1: Load the substrate 5 to be processed to the set cladding processing area. In the specific implementation process, the substrate 5 is moved to the processing area through the loading and unloading system, and then the substrate 5 to be processed is positioned and detected by the visual monitoring system. If the substrate 5 to be processed is a shaft, the substrate 5 is positioned and fixed by the machine tool.
[0033] Step 2: Surface cleaning and preheating of the substrate 5. In this step, the surface of the substrate to be processed is mainly treated by laser rust removal and preheating by the laser cleaning device 9. The laser cleaning method can effectively ensure that the base material of the substrate 5 is not damaged while removing dirt and rust.
[0034] Step 3: After positioning the substrate surface of the substrate 5 after step 2, the substrate 5 is driven to move according to the set cladding process, and step 4 is performed at the same time.
[0035] Step 4: Load the self-fluxing alloy powder 2 above the positioned substrate surface, and use the first energy cladding laser 6 to act on the self-fluxing alloy powder 2 at the same time, so that the self-fluxing alloy powder 2 is in a molten state. The molten self-fluxing alloy powder 2 falls under the action of gravity and the powder-carrying airflow to form a molten pool 3 on the substrate surface; at the same time, use the second energy cladding laser 7 to act on the substrate surface outside the molten pool 3 to melt the substrate surface of the substrate 5. Among them, the self-fluxing alloy powder 2 is formed by combining different types of powders such as nickel-based, cobalt-based, and iron-based alloys. The laser energy density of the first energy cladding laser 6 is 9 times the laser energy density of the second energy cladding laser 7. The sum of the laser energy densities of the first energy cladding laser 6 and the second energy cladding laser 7 is the output laser energy density of the laser cladding head. The maximum output laser energy density of the laser cladding head is 3kW / cm 2 , and the spot diameter of the first energy cladding laser 6 is less than 1 mm.
[0036] Laser cladding technology is to coaxially output the laser beam and alloy powder from the cladding head, and realize it through the laser cladding head composed of an optical path system and a powder feeding nozzle. This configuration reduces the need for additional heat to melt the powder before entering the molten pool, thereby shortening the duration of the molten pool; the alloy powder has a separate channel different from the laser beam in the cladding head, and the powder feeder outputs the powder to the cladding head through a dedicated pipeline for cladding work. The powder participates in the cladding process together with the laser. In the present invention, 90% of the laser energy is used to melt the alloy powder to form a molten state, and the remaining laser energy is not wasted, but is used to melt the surface of the substrate, that is, to melt the substrate surface at the edge of the molten pool 3. Under the action of gravity, the molten self-fluxing alloy powder 2 combines with the substrate 5 to form a metallurgical bonding interface. This energy distribution method applies more laser energy to the self-fluxing alloy powder 2 to form a molten state, which causes less thermal damage to the substrate, so the substrate will not be damaged. In addition, since the energy density of the second energy cladding laser 7 is small, it is used to melt the surface of the substrate at the edge of the molten pool 3, which not only reduces the loss to the substrate, but also facilitates the firm bonding of the self-fluxing alloy powder 2 and the substrate. Since the heat input is small, this method helps to maintain the integrity and performance of the workpiece.
[0037] The spot diameter of traditional laser cladding is about 2mm-4mm, while the spot diameter of the ultra-high-speed laser cladding method of the present invention is less than 1mm. Under the same laser energy input conditions, the laser energy density in the small spot area is higher. In traditional laser cladding technology, the laser energy density is about 70W / cm 2 -150W / cm 2 , while the laser energy density of ultra-high-speed laser cladding can reach up to 3kW / cm 2 .
[0038] like Figure 1 As shown in the figure, in the traditional laser cladding process, the dilution rate of the substrate coating is high and the heat affected zone is large. The unmelted powder will be directly sent into the molten pool 3, resulting in a large roughness of the substrate surface coating after cladding. Moreover, because the energy of the laser mostly acts directly on the substrate surface, this is also the main reason for the increase in the thermal type of the traditional laser cladding substrate, which ultimately leads to a decrease in the substrate yield and low processing efficiency of the enterprise. Figure 2 As shown, the ultra-high-speed laser cladding method of the present invention changes the convergence position of the laser, powder and molten pool, so that the powder convergence point is higher than the molten pool 3. The converged powder is melted by the laser energy and then enters the molten pool 3 under the action of gravity, solving the problems of large substrate thermal profile variation and low processing efficiency caused by traditional laser cladding. Figure 3 a and b show the effect of the conventional laser cladding and the laser cladding of the present invention on the substrate 5 after actual cladding. Figure 3 It can be seen from FIG. 5 that, through the laser cladding method of the present invention, the surface cladding layer 4 of the substrate 5 after cladding has high flatness and is dense, and no secondary machining is required subsequently.
[0039] In the present invention, the cladding process is 0.5m 2 / h-2m 2 / h. For example, the substrate 5 to be processed is a shaft, and the substrate 5 is positioned and fixed by the machine tool. During the cladding process, the substrate 5 will rotate at a uniform speed, and the molten alloy powder will be metallurgically combined with the substrate under the action of gravity. Under the action of process parameters, the cladding head sprays powder while the substrate 5 rotates at the same time, and the molten powder can be evenly spread on the surface of the substrate. The traditional cladding line speed is generally 600mm / min-800mm / min, that is, the cladding efficiency is 0.15m 2 / h, and after adopting the ultra-high-speed laser cladding method of the present invention, the overall processing efficiency is 3-5 times that of traditional cladding.
[0040] In order to improve the melting efficiency above the molten pool 3 and meet the surface melting of the substrate surface, the second energy cladding laser 7 of the present invention is provided with two laser beams with the first energy cladding laser 6 as the symmetry axis. Both laser beams are irradiated on the molten pool 3 at an angle, and the laser beams are also irradiated on the edge of the molten pool 3 on the side opposite to the laser beam. The angle between the second energy cladding laser 7 and the first energy cladding laser 6 is 15°-30°.
[0041] Step 5: When the substrate surface on which the cladding layer 4 is to be processed is processed, the quality of the cladding layer 4 on the substrate surface is inspected by a visual monitoring device 8 to complete the processing.
[0042] Example 2
[0043] like Figure 4 As shown, an ultra-high-speed laser cladding system using the ultra-high-speed laser cladding method described above includes a visual monitoring device 8, a laser cleaning device 9, a laser cladding head 10, and a bracket 11. The visual monitoring device 8, the laser cleaning device 9, and the laser cladding head 10 are all installed on the bracket 11, and a manipulator connecting flange 12 is also installed on the bracket 11 to realize the movement of the system driven by the manipulator.
[0044] The visual monitoring device 8 is used to monitor whether the substrate 5 is fed to the set cladding processing area, and to perform quality inspection on the cladding layer 4 on the surface of the substrate. Specifically, the visual monitoring device 8 is an industrial visual system, which is composed of industrial cameras, lenses, communication output signal receiving devices, host computers and other components. The visual monitoring device 8 mainly positions the processing substrate 5 through the project equipment parameter settings before the cladding work, and monitors and feedbacks the cladding quality of the substrate 5 in real time during the cladding process. The industrial computer can timely adjust and improve the cladding process parameters through the feedback results, so as to achieve an optimal cladding quality. The whole process is more intelligent and lightweight, saving the investment cost of the enterprise.
[0045] The laser cleaning device 9 is used to perform step 2 of the ultra-high-speed laser cladding method. Specifically, the laser cleaning device 9 is mainly composed of a laser cleaning gun head connected to a pulsed laser. Before the ultra-high-speed cladding processing of the substrate 5, the dirt or rust on the surface of the substrate can be laser cleaned and rusted by setting the system parameters, and the surface of the substrate can be preheated in advance. The benefit of preheating is that during the subsequent cladding processing of the substrate 5, less laser energy is required to act on the surface of the substrate.
[0046] The laser cladding head 10 is used to perform step 4 of the ultra-high-speed laser cladding method. In this way, the integrated system design of laser cleaning preheating, cladding, and detection is realized. It should be noted that the laser cladding head 10 can use 1 or 2 collimating lenses and 1 focusing lens, and the lens body material is preferably silicon dioxide with a purity of more than 90% to reduce the loss of laser energy.
[0047] The above is only a preferred embodiment of the present invention. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the structure of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent.
Claims
1. An ultra-high-speed laser cladding method, characterized in that: The method comprises the following steps: Step 1: Loading the substrate (5) to a set cladding processing area; Step 2: performing surface cleaning and preheating treatment on the substrate (5); Step 3: After positioning the substrate surface of the substrate (5) after step 2, the substrate (5) is driven to move according to the set cladding process, and step 4 is performed at the same time; Step 4: self-fluxing alloy powder (2) is loaded above the positioned surface of the substrate, and a first energy cladding laser (6) is used to act on the self-fluxing alloy powder (2) to make the self-fluxing alloy powder (2) molten. The molten self-fluxing alloy powder (2) falls under the action of gravity and powder-carrying airflow to form a molten pool (3) on the surface of the substrate; at the same time, a second energy cladding laser (7) is used to act on the substrate surface outside the molten pool (3) to melt the substrate surface of the substrate (5); Step 5: When the substrate surface on which the cladding layer (4) is to be processed is completed, the cladding layer (4) on the substrate surface is quality inspected to complete the processing.
2. The ultra-high speed laser cladding method according to claim 1, characterized in that: The laser energy density of the first energy cladding laser (6) is 8-9.5 times the laser energy density of the second energy cladding laser (7).
3. The ultra-high speed laser cladding method according to claim 2, characterized in that: The sum of the laser energy densities of the first energy cladding laser (6) and the second energy cladding laser (7) is the output laser energy density of the laser cladding head.
4. The ultra-high speed laser cladding method according to claim 3, characterized in that: The output laser energy density of the laser cladding head is 2 kW / cm 2 -3kW / cm 2 .
5. An ultra-high speed laser cladding method according to any one of claims 1 to 4, characterized in that: The spot diameter of the first energy cladding laser (6) is less than 1 mm.
6. The ultra-high speed laser cladding method according to claim 1, characterized in that: The cladding process is 0.5m 2 / h-2m 2 / h.
7. The ultra-high speed laser cladding method according to claim 1, characterized in that: The second energy cladding laser (7) is provided with two laser beams, both of which are irradiated obliquely onto the molten pool (3), and the laser beams are also irradiated onto the edge of the molten pool (3) on the side opposite to the laser beam.
8. The ultra-high speed laser cladding method according to claim 7, characterized in that: The angle between the second energy cladding laser (7) and the first energy cladding laser (6) is 15°-30°.
9. An ultra-high-speed laser cladding system using the ultra-high-speed laser cladding method according to claims 1 to 8, characterized in that: include: A visual monitoring device (8) is used to monitor whether the substrate (5) is loaded into a set cladding processing area, and to perform quality inspection on the cladding layer (4) on the surface of the substrate; A laser cleaning device (9), used to perform step 2 of the ultra-high-speed laser cladding method; A laser cladding head (10) is used to perform step 4 of the ultra-high-speed laser cladding method.
10. The ultra-high speed laser cladding system according to claim 9, characterized in that: The system also comprises a bracket (11), the visual monitoring device (8), the laser cleaning device (9) and the laser cladding head (10) are all mounted on the bracket (11), and a manipulator connecting flange (12) is also mounted on the bracket (11).