Temperature measuring device and temperature measuring method for laser cladding molten pool

Abstract

The invention relates to the technical field of laser cladding temperature monitoring, in particular to a laser cladding molten pool temperature measuring device and method.The laser cladding molten pool temperature measuring device comprises an adjusting support installed on a laser cladding head, a color industrial camera is installed at the movable end of the adjusting support, and a filtering assembly is installed on a camera lens of the color industrial camera; the adjusting support comprises a fixing part connected with the laser cladding head, a position adjusting part is installed on the fixing part, an angle rotating part is installed at the movable end of the position adjusting part, and the color industrial camera is installed on the angle rotating part. The temperature of the molten pool can be accurately monitored through the molten pool temperature measuring device.

Description

Technical Field

[0001] The present invention relates to the technical field of laser cladding temperature monitoring, and in particular to a laser cladding molten pool temperature measuring device and a temperature measuring method. Background Art

[0002] Laser cladding technology is the most cutting-edge technology in additive manufacturing. Its main principle is to form a high-temperature molten pool on the surface of the workpiece through high-energy laser beam irradiation, melt the cladding layer material and the substrate material, and realize the metallurgical bonding of the cladding layer material and the substrate material. It can significantly improve the corrosion resistance, wear resistance, heat resistance, oxidation resistance and other properties of the substrate. It has the advantages of good flexibility, high material utilization, high cladding efficiency and good bonding strength between the cladding layer and the substrate.

[0003] In the laser cladding process, the temperature signal is the most intuitive and significant parameter affecting the quality of laser cladding. The laser cladding process is to irradiate the powder or metal wire with a high-energy laser beam, melt and cover the surface of the substrate to form a cladding layer. The molten pool is the carrier of the temperature signal. The temperature change of the molten pool is closely related to the macroscopic morphology, microstructure and forming quality of the cladding layer. The influence of the molten pool temperature on the forming quality is mainly manifested in that too high a temperature will cause the cladding layer to be overburned and the heat-affected zone of the substrate to be too large; too low a temperature will cause uneven and insufficient melting of the powder, affecting the dimensional accuracy of the cladding layer.

[0004] According to the acquisition method of the molten pool temperature signal, it can be divided into two categories: contact and non-contact. Contact temperature measurement refers to the method in which the temperature measuring element is in direct contact with the object to be measured. Based on the heat conduction between the two, the temperature of the temperature measuring element changes with the change of the object to be measured, and is manifested through the change of other parameters. The advantages of contact temperature measurement are that the temperature measuring element has a simple structure, is convenient and reliable, and has high measurement accuracy. However, the disadvantages are that there is a delay in temperature measurement, and contact temperature measurement cannot be used directly when the temperature is too high. During the laser cladding process, the molten pool reacts violently and the temperature is too high, which is not suitable for temperature measurement systems that require long-term monitoring. Therefore, non-contact measurement is usually used in the field of laser cladding temperature monitoring.

[0005] The non-contact temperature measurement method does not directly contact the molten pool and does not affect the normal processing of laser cladding. Its main advantages are wide measurement range, high accuracy, small target measurement, and strong anti-interference ability. At present, the non-contact temperature measurement method of the molten pool usually adopts infrared two-color thermometer, pyrometer, infrared thermal imager, etc. However, various temperature measurement technologies differ in measurement range, accuracy, response time, etc. Infrared thermal imagers are expensive and not suitable for industrial production. Pyrometers have slow response time. Infrared two-color thermometers are easily affected by the high brightness of the molten pool, and the temperature measurement results are inaccurate. Therefore, it is very necessary to develop a molten pool temperature measurement system and method that is low-cost, fast in response time, strong in anti-interference ability, and can be actually applied to industrial production. Summary of the invention

[0006] The object of the present invention is to provide a laser cladding molten pool temperature measuring device and a temperature measuring method to solve the above-mentioned problems and to accurately monitor the molten pool temperature through the molten pool temperature measuring device.

[0007] To achieve the above object, the present invention provides the following solutions:

[0008] A laser cladding molten pool temperature measuring device comprises an adjusting bracket installed on a laser cladding head, a color industrial camera is installed on the movable end of the adjusting bracket, a filter assembly is installed on the camera lens of the color industrial camera, the adjusting bracket comprises a fixing part connected to the laser cladding head, a position adjusting part is installed on the fixing part, an angle rotating part is installed on the movable end of the position adjusting part, and the color industrial camera is installed on the angle rotating part.

[0009] Preferably, the position adjustment member includes a bracket clamp detachably connected to the laser cladding head, an aluminum alloy profile is detachably connected to the bracket clamp, the aluminum alloy profile is horizontally arranged, a locking clamp is slidably installed on the outer side of the aluminum alloy profile, a height adjustment device is installed at the bottom end of the aluminum alloy profile, the angle rotation member is slidably installed at the bottom end of the height adjustment device, and the sliding direction of the angle rotation member is perpendicular to the sliding direction of the locking clamp.

[0010] Preferably, the angle rotating member includes a camera connecting member slidably connected to the bottom of the height adjusting device, the bottom end of the height adjusting device is fixedly connected to a slide rail groove, the camera connecting member is slidably installed in the slide rail groove, and the color industrial camera is installed on the camera connecting member by bolts.

[0011] Preferably, the spectral response range of the color industrial camera is 400nm-1000nm, the exposure time is 20μs-1s, the resolution is 2048×1536, the frame rate is 125fps, the dynamic range is 71.62db, and the spectral response peaks of the color industrial camera are: red light 610nm, green light 529nm, and blue light 460nm.

[0012] Preferably, the focal length of the camera lens is 12-36 mm, the resolution is 5 million, the aperture range is F2.8-16, the weight is 158 g, and the optical distortion is less than 0.95%.

[0013] Preferably, the filter assembly includes a threaded adapter ring II which is detachably connected to the camera lens, a bandpass filter is installed on the threaded adapter ring II, a neutral attenuation plate is installed on the end of the bandpass filter away from the threaded adapter ring II, a threaded adapter ring I is installed on the end of the neutral attenuation plate away from the threaded adapter ring II, and a magnifying lens is installed on the end of the threaded adapter ring I away from the bandpass filter.

[0014] Preferably, the filtering range of the bandpass filter is 500nm-700nm; the attenuation ratio of the neutral attenuation plate is 1.2%; and the magnification of the magnifying lens is 4 times.

[0015] A method for colorimetric temperature measurement of a molten pool, the method is implemented based on the temperature measurement device described in the above scheme, and specifically comprises the following steps:

[0016] S1: Based on Planck's radiation law, obtain the function expression of the grayscale ratio and temperature of the image pixel array points;

[0017] S2: Select the response peak bands of red light R and green light G at 630nm and 529nm as the monitoring bands, obtain the relationship curve between R / G and temperature T through the blackbody furnace calibration experiment, and get the L value by fitting the curve; R / G is the grayscale ratio of the image pixel array point, T is the absolute temperature of the blackbody, and L is the calibration factor of the colorimetric temperature measurement model;

[0018] S3: Laser cladding process forms a molten pool, and a color industrial camera with optical components is used to capture the image information of the molten pool;

[0019] S4: The color industrial camera transmits the collected molten pool image information to the computer. The computer analyzes the red-green R / G ratio of each pixel in the image based on the OpenCV library of python software, and calculates the temperature by applying the fitting formula obtained in step S1. The computer generates and exports a pseudo-color image of the molten pool temperature and a line graph of the average molten pool temperature.

[0020] S5: Display and save the molten pool temperature information, laying the foundation for subsequent process optimization and feedback control.

[0021] Preferably, in step S1, for an object at a temperature of T, under a wavelength of λ, the monochromatic radiance N can be expressed as:

[0022]

[0023] In the formula, N is the blackbody spectral radiation intensity; T is the absolute temperature of the blackbody; h is Planck's constant; c is the speed of light; k represents the Boltzmann constant; C1 represents the first radiation constant; C2 represents the second radiation constant; and m is the monochromatic emissivity of the object.

[0024] When the radiation wavelength is short and the temperature is lower than 3000K, the Wien formula can be used to approximately replace the Planck formula. The ratio of monochromatic radiance of light in different wavelengths of the molten pool is:

[0025]

[0026] The monochromatic emissivity m of most objects is approximately considered to be a constant in a narrowband band, so m = m. After simplification, the colorimetric temperature measurement formula can be obtained:

[0027]

[0028] The R and G expressions of each point in the pixel array can be simplified based on the integral mean value theorem:

[0029] R=F·(4×10 -7 )N(λ ξ ,T)r(λ ξ )=K r ·N(λ r , T)

[0030] G=F·(4×10 -7 )N(λ μ ,T)g(λ μ )=K g ·N(λ g , T)

[0031] Substituting into the colorimetric temperature measurement formula, we can get the function expression of the grayscale ratio value and temperature of the image pixel array point:

[0032]

[0033] Where R / G is the grayscale ratio of the image pixel array, C2 is the second radiation constant, and λ g =529nm,λ r =630nm, L = ln K g / K r , the L value is the calibration factor of the colorimetric temperature measurement model, which is determined by the spectral sensitivity characteristics of the camera.

[0034] The present invention has the following technical effects:

[0035] (1) The present invention overcomes the drawbacks of traditional infrared thermal imagers for temperature measurement, which are high cost and not applicable to actual industrial production. In addition, the laser cladding processing environment is harsh and the equipment loss is large. The present invention uses a low-cost color industrial camera with an optical element system to shoot the molten pool, which is low-cost, easy to operate and maintain.

[0036] (2) The present invention can monitor the temperature of the molten pool during the laser cladding process, and then adjust the cladding process parameters, effectively ensuring the stability of the part forming quality and avoiding some defects caused by molten pool temperature fluctuations, such as powder sticking, pores, and cladding layer protrusions.

[0037] (3) The camera bracket designed in the present invention has good stability and can ensure the four degrees of freedom and flexibility of the camera. The lens and the laser cladding head are installed at a certain angle, and the lens and the laser head are moved synchronously through the bracket to achieve real-time acquisition of the molten pool image. The advantage of the paraxial acquisition method is that there is no need to change the internal structure of the laser cladding head, it is easy to install and has a low cost.

[0038] (4) The optical component system constructed by the present invention, including the bandpass filter, the neutral attenuation plate, etc., can not only significantly increase the upper limit of the measured temperature, but also effectively filter out the high-brightness signal appearing in the cladding process, thereby avoiding inaccurate temperature measurement results caused by overexposure of the camera and enhancing the reliability of the measurement results. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0040] Figure 1 It is a structural schematic diagram of the temperature measuring device for laser cladding molten pool of the present invention;

[0041] Figure 2 It is a schematic diagram of the optical component system of the molten pool temperature measuring device of the present invention;

[0042] Figure 3 The relationship curve between R / G and temperature T obtained for the blackbody furnace calibration experiment.

[0043] Among them, 101, laser cladding head; 102, substrate; 103, bracket clamp; 104, aluminum alloy profile; 105, locking clamp; 106, height adjustment device; 107, camera connector; 201, magnifying lens; 202, thread adapter ring I; 203, neutral attenuation plate; 204, bandpass filter; 205, thread adapter ring II; 206, camera lens; 207, color industrial camera; 208, thread interface converter. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0046] Reference Figures 1 to 3 As shown, this embodiment provides

[0047] A laser cladding molten pool temperature measuring device comprises an adjusting bracket installed on a laser cladding head 101, a color industrial camera 207 is installed on a movable end of the adjusting bracket, a filter component is installed on a camera lens 206 of the color industrial camera 207, the adjusting bracket comprises a fixing part connected to the laser cladding head 101, a position adjusting part is installed on the fixing part, an angle rotating part is installed on the movable end of the position adjusting part, and the color industrial camera 207 is installed on the angle rotating part.

[0048] A further optimized solution is that the position adjustment part includes a bracket clamp 103 detachably connected to the laser cladding head 101, an aluminum alloy profile 104 is detachably connected to the bracket clamp 103, the aluminum alloy profile 104 is horizontally arranged, a locking clamp 105 is slidably installed on the outer side of the aluminum alloy profile 104, a height adjustment device 106 is installed at the bottom end of the aluminum alloy profile 104, an angle rotating part is slidably installed at the bottom end of the height adjustment device 106, and the sliding direction of the angle rotating part is perpendicular to the sliding direction of the locking clamp 105.

[0049] A further optimized solution is that the angle rotating part includes a camera connecting part 107 slidably connected to the bottom of the height adjustment device 106, the bottom end of the height adjustment device 106 is fixedly connected with a slide rail groove, the camera connecting part 107 is slidably installed in the slide rail groove, and the color industrial camera 207 is installed on the camera connecting part 107 by bolts, and the angle adjustment of the color industrial camera (207) is completed by adjusting the tightness of the bolts.

[0050] The locking clamp 105, the aluminum alloy profile 104, the height adjustment device 106 and the slide rail groove can make the color industrial camera 207 have the translation freedom along the xyz axis. The setting of the camera connector 107 can make the color industrial camera 207 rotate around the x axis, which can accurately control the position of the camera relative to the cladding head, and the rotation freedom of the x axis allows the camera to adjust the viewing angle relative to the molten pool. Through experimental testing, it was determined that the distance between the front end of the lens and the center of the laser focal length is 15mm, and when the lens elevation angle is 45°, the shooting effect of the molten pool is optimal.

[0051] The thread interface converter 208 is fixedly connected to the color industrial camera 207 through three M3 threaded holes. The center of the thread converter is an M6 threaded hole, and the color industrial camera 207 can be fixed to the camera connector 107 by bolts to achieve M3-M6 thread conversion.

[0052] Further optimization scheme, the spectral response range of color industrial camera 207 is 400nm-1000nm, the exposure time is 20μs-1s, the resolution is 2048H×1536V, the frame rate is 125fps, the dynamic range is 71.62db, and the spectral response peaks of color industrial camera are: red light 610nm, green light 529nm, blue light 460nm.

[0053] According to a further optimization scheme, the focal length of the camera lens 206 is 12-36 mm, the resolution is 5 million, the aperture range is F2.8-16, the weight is 158 g, and the optical distortion is less than 0.95%.

[0054] A further optimized solution is that the filter assembly includes a threaded adapter ring II 205 detachably connected to a camera lens 206, a bandpass filter 204 is mounted on the threaded adapter ring II 205, a neutral attenuation plate 203 is mounted on the end of the bandpass filter 204 away from the threaded adapter ring II 205, a threaded adapter ring I 202 is mounted on the end of the neutral attenuation plate 203 away from the threaded adapter ring II 205, and a magnifying lens 201 is mounted on the end of the threaded adapter ring I 202 away from the bandpass filter 204.

[0055] According to a further optimization scheme, the filtering range of the bandpass filter 204 is 500nm-700nm; the attenuation ratio of the neutral attenuation plate 203 is 1.2%, and the magnification of the magnifying lens 201 is 4 times.

[0056] A method for colorimetric temperature measurement of a molten pool, the method is implemented based on the temperature measurement device of the above scheme, and specifically comprises the following steps:

[0057] S1: Based on Planck's radiation law, obtain the function expression of the grayscale ratio and temperature of the image pixel array points;

[0058] S2: Select the response peak bands of red light R and green light G at 630nm and 529nm as the monitoring bands, obtain the relationship curve between R / G and temperature T through the blackbody furnace calibration experiment, and get the L value by fitting the curve; R / G is the grayscale ratio of the image pixel array point, T is the absolute temperature of the blackbody, and L is the calibration factor of the colorimetric temperature measurement model;

[0059] S3: Laser cladding process forms a molten pool, and a color industrial camera with optical components is used to capture the image information of the molten pool;

[0060] S4: The color industrial camera 207 transmits the collected molten pool image information to the computer. The computer analyzes the red-green R / G ratio of each pixel in the image based on the OpenCV library of python software, and calculates the temperature by applying the fitting formula obtained in step S1. The computer generates and exports a pseudo-color image of the molten pool temperature and a line graph of the average molten pool temperature.

[0061] S5: Display and save the molten pool temperature information, laying the foundation for subsequent process optimization and feedback control.

[0062] To further optimize the scheme, in step S1, for an object with a temperature of T and a wavelength of λ, the monochromatic radiance Nλ,T can be expressed as:

[0063]

[0064] Where Nλ,T is the blackbody spectral radiation intensity; T is the absolute temperature of the blackbody; h is Planck's constant; c is the speed of light; k represents the Boltzmann constant; C1 represents the first radiation constant; C2 represents the second radiation constant; mλ,T is the monochromatic emissivity of the object.

[0065] When the radiation wavelength is short and the temperature is lower than 3000K, the Wien formula can be used to approximately replace the Planck formula. The ratio of monochromatic radiance of light in different wavelengths of the molten pool is:

[0066]

[0067] The monochromatic emissivity mλ,T of most objects is approximately considered to be a constant in a narrowband band, so mλ1,T=mλ2,T. After simplification, the colorimetric temperature measurement formula can be obtained:

[0068]

[0069] The R and G expressions of each point in the pixel array can be simplified based on the integral mean value theorem:

[0070] R=F·(4×10 -7 )N(λ ξ ,T)r(λ ξ )=K r ·N(λ r ,T)

[0071] G=F·(4×10 -7 )N(λ μ ,T)g(λ μ )=K g ·N(λ g , T)

[0072] Substituting into the colorimetric temperature measurement formula, we can get the function expression of the grayscale ratio value and temperature of the image pixel array point:

[0073]

[0074] Where R / G is the grayscale ratio of the image pixel array, C2 is the second radiation constant, and λ g =529nm,λ r =630nm, L = ln K g / K r , the L value is the calibration factor of the colorimetric temperature measurement model, which is determined by the spectral sensitivity characteristics of the camera.

[0075] Assembly of color industrial camera 207 and filter components:

[0076] 1. The threaded interface converter 208 is fixedly connected to the bottom of the color industrial camera 207 through the three M3 threaded holes at the bottom.

[0077] 2. Install the camera lens 206 on the color industrial camera 207 to form the imaging basis of the system.

[0078] 3. Install a thread adapter ring II 205 at the front end of the camera lens 206 to facilitate the connection of subsequent optical components.

[0079] 4. Install the bandpass filter 204 and the neutral attenuation plate 203 on the threaded adapter ring II 205 in sequence, ensuring that the filters are arranged in a predetermined order to achieve the desired molten pool imaging effect.

[0080] 5. The magnifying lens 201 is installed on the neutral attenuation plate 203 through the threaded adapter ring I 202, wherein the magnifying lens 201 is located at the outermost end of the optical component system to magnify the molten pool imaging and prevent powder splashing.

[0081] Through the orderly assembly of the above components, the molten pool imaging function is realized, wherein the coordinated work of each optical element provides the system with the required spectral transmittance characteristics and imaging magnification function.

[0082] Adjustment bracket installation:

[0083] 1. Use M6 bolts and corresponding nuts to fix the bracket clamp 103 to the outer wall of the laser cladding head 101, ensuring that both sides are tightened to achieve a tight combination.

[0084] 2. A rubber pad is embedded in the part where the inner wall of the bracket clamp 103 contacts the cladding head 101 to increase the friction and reduce the damage to the contact area of ​​the cladding head.

[0085] 3. The aluminum alloy profile 104 is fixed through two M6 threaded holes at the front end of the bracket clamp 103 to enhance the stability of the overall structure.

[0086] 4. Assemble the locking clamp 105 onto the aluminum alloy profile and lock its upper end by tightening to ensure that it is firmly fixed to the profile.

[0087] 5. The upper end of the height adjustment device 106 is connected to the lower end of the locking clamp 105 by a cylindrical nesting method to achieve height adjustability.

[0088] 6. The front end buckle of the camera connecting member 107 is designed to be detachable so that it can be clamped in the slide rail groove of the height adjustment device 106 and tightened and locked.

[0089] 7. Fix the thread converter 208 to the color camera 207 through three M3 threaded holes, and use M6 bolts to fix the camera connector 107 to the M6 ​​threaded hole in the center of the thread converter 208 to ensure stable matching between the camera connector 107 and the color camera 207. This structure realizes the precise docking and fixation of the cladding head 101 and the color industrial camera 207, providing a stable support and adjustment mechanism for monitoring the molten pool temperature during the laser cladding process.

[0090] Temperature calibration:

[0091] The temperature calibration interval of the experiment was set to 1000°C to 1600°C. The temperature of the blackbody furnace was gradually increased, and every 50°C was used as a collection point. A neutral attenuation plate (203), a bandpass filter (204) and a magnifying lens (201) were installed in front of the camera lens to keep consistent with the actual temperature measurement. The automatic gain and automatic white balance functions of the camera were turned off, and the white balance coefficient was set to 1.7734. Eight images were collected at each collection point, and the average value was taken as the data of the calibration temperature point. The R / G value of each calibration point was calculated and corresponded to the calibration temperature value. The R / G value was set as x, the temperature was set as y, the unknown quantity L was fitted, and the colorimetric temperature measurement formula was obtained.

[0092] Camera focus:

[0093] 1. Adjust the locking clamp 105, the height adjustment device 106, and the camera connector 107 to ensure that the color industrial camera 207, the filter assembly, and the cladding head 101 are in the same plane in terms of spatial position. The height adjustment device 106 can be set in the form of an inner and outer sleeve, and a bolt is threadedly connected to the outer sleeve to achieve height adjustment.

[0094] 2. Since the filter assembly is mainly suitable for high-brightness molten pools, pictures taken in normal environments are too dark. Therefore, different accessories need to be replaced during the focusing process of the filter assembly. Specifically, the neutral attenuation plate 203 and the bandpass filter 204 are replaced with two lens-free threaded adapter rings.

[0095] 3. By adjusting the angle of the filter component and the focal length of the camera lens 206, the light spot is accurately and clearly imaged at the center of the lens.

[0096] 4. Fix and adjust all joints of the bracket according to Figure 2 In the order shown, remove the thread adapter ring I 202 and the thread adapter ring II 205 in turn, and reinstall the appropriate magnifying lens 201 to complete the focusing.

[0097] Step 5: Operate the cladding equipment to start processing.

[0098] The camera synchronously collects the molten pool signal and transmits it to the computer for analysis and processing through the USB3.0 interface. Based on the colorimetric temperature measurement formula calibrated and fitted above, a pseudo-color image of the molten pool temperature is derived.

[0099] The present invention adopts the above method to accurately monitor the molten pool temperature during the laser cladding process.

[0100] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0101] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A laser cladding molten pool temperature measuring device, characterized in that: The invention comprises an adjustment bracket installed on a laser cladding head (101), a color industrial camera (207) being installed on a movable end of the adjustment bracket, a filter assembly being installed on a camera lens (206) of the color industrial camera (207), the adjustment bracket comprising a fixing part connected to the laser cladding head (101), a position adjustment part being installed on the fixing part, an angle rotation part being installed on the movable end of the position adjustment part, and the color industrial camera (207) being installed on the angle rotation part.

2. A laser cladding molten pool temperature measuring device according to claim 1, characterized in that: The position adjustment member comprises a support clamp (103) detachably connected to the laser cladding head (101); an aluminum alloy profile (104) is detachably connected to the support clamp (103); the aluminum alloy profile (104) is arranged horizontally; a locking clamp (105) is slidably mounted on the outer side of the aluminum alloy profile (104); a height adjustment device (106) is mounted at the bottom end of the aluminum alloy profile (104); the angle rotation member is slidably mounted at the bottom end of the height adjustment device (106); and the sliding direction of the angle rotation member is perpendicular to the sliding direction of the locking clamp (105).

3. The laser cladding molten pool temperature measuring device according to claim 2, characterized in that: The angle rotating member includes a camera connecting member (107) slidably connected to the bottom of the height adjusting device (106); the bottom end of the height adjusting device (106) is fixedly connected to a slide rail groove; the camera connecting member (107) is slidably installed in the slide rail groove; and the color industrial camera (207) is installed on the camera connecting member (107) by bolts.

4. The laser cladding molten pool temperature measuring device according to claim 1, characterized in that: The color industrial camera (207) has a spectral response range of 400nm-1000nm, an exposure time of 20μs-1s, a resolution of 2048(H)×1536(V), a frame rate of 125fps, a dynamic range of 71.62db, and spectral response peaks of the color industrial camera are: red light 610nm, green light 529nm, and blue light 460nm.

5. The laser cladding molten pool temperature measuring device according to claim 1, characterized in that: The camera lens (206) has a focal length of 12-36 mm, a resolution of 5 million, an aperture range of F2.8-16, a weight of 158 g, and an optical distortion of <0.95%.

6. The laser cladding molten pool temperature measuring device according to claim 1, characterized in that: The filter assembly comprises a threaded adapter ring II (205) detachably connected to the camera lens (206); a bandpass filter (204) is mounted on the threaded adapter ring II (205); a neutral attenuation plate (203) is mounted on one end of the bandpass filter (204) away from the threaded adapter ring II (205); a threaded adapter ring I (202) is mounted on one end of the neutral attenuation plate (203) away from the threaded adapter ring II (205); and a magnifying lens (201) is mounted on one end of the threaded adapter ring I (202) away from the bandpass filter (204).

7. The laser cladding molten pool temperature measuring device according to claim 6, characterized in that: The filtering range of the bandpass filter (204) is 500nm-700nm; the attenuation ratio of the neutral attenuation plate (203) is 1.2%; and the magnification of the magnifying lens (201) is 4 times.

8. A method for colorimetric temperature measurement of a molten pool, characterized in that: The method is implemented based on the temperature measuring device according to any one of claims 1 to 7, and specifically comprises the following steps: S1: Based on Planck's radiation law, obtain the function expression of the grayscale ratio and temperature of the image pixel array points; S2: Select the response peak bands of red light R and green light G at 630nm and 529nm as the monitoring bands, obtain the relationship curve between R / G and temperature T through the blackbody furnace calibration experiment, and get the L value by fitting the curve; R / G is the grayscale ratio of the image pixel array point, T is the absolute temperature of the blackbody, and L is the calibration factor of the colorimetric temperature measurement model; S3: Laser cladding process forms a molten pool, and a color industrial camera with optical components is used to capture the image information of the molten pool; S4: the color industrial camera (207) transmits the collected molten pool image information to a computer, and the computer analyzes the red / green R / G ratio of each pixel in the image based on the OpenCV library of python software, and calculates the temperature by applying the fitting formula obtained in step S1, and the computer generates and exports a pseudo-color image of the molten pool temperature and a line graph of the average molten pool temperature; S5: Display and save the molten pool temperature information, laying the foundation for subsequent process optimization and feedback control.

9. The method for colorimetric temperature measurement of a molten pool according to claim 8, characterized in that: In step S1, for an object with a temperature of T and a wavelength of λ, the monochromatic radiance N(λ, T) can be expressed as: Where N(λ, T) is the blackbody spectral radiation intensity; T is the absolute temperature of the blackbody; h is Planck's constant; c is the speed of light; k represents the Boltzmann constant; C1 represents the first radiation constant; C2 represents the second radiation constant; m(λ, T) is the monochromatic emissivity of the object. When the radiation wavelength is short and the temperature is lower than 3000K, the Wien formula can be used to approximately replace the Planck formula. The ratio of monochromatic radiance of light in different wavelengths of the molten pool is: The monochromatic emissivity m(λ, T) of most objects is approximately considered to be a constant in a narrowband band, so m(λ1, T) = m(λ2, T). After simplification, the colorimetric temperature measurement formula can be obtained: The R and G expressions of each point in the pixel array can be simplified based on the integral mean value theorem: R=F·(4×10 -7 )N(λ ξ ,T)r(λ ξ )=K r ·N(λ r ,T) G=F·(4×10 -7 )N(λ μ ,T)g(λ μ )=K g ·N(λ g ,T) Substituting into the colorimetric temperature measurement formula, we can get the function expression of the grayscale ratio value and temperature of the image pixel array point: Where R / G is the grayscale ratio of the image pixel array, C2 is the second radiation constant, and λ g =529nm,λ r =630nm, L = ln K g / K r , the L value is the calibration factor of the colorimetric temperature measurement model, which is determined by the spectral sensitivity characteristics of the camera.

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