A laser ultrasonic defect detection device and method for hot metal components

Abstract

The application discloses a kind of hot metal component laser ultrasonic defect detection device and detection method, detection device includes high temperature heating module, laser excitation module, laser detection module, mobile scanning automatic focusing module and signal acquisition and control module;Laser excitation module and laser detection module excite laser, and by mobile scanning automatic focusing module will excitation laser and detection laser be incident to the different positions of the metal component to be measured, and reflected detection laser is transferred to signal acquisition and control analysis module by optical probe and interferometer and is handled and imaging.The detection device of the application has the functions of metal component high temperature heating simulation, detection laser automatic focusing, fast mobile scanning, defect automatic imaging, can efficiently realize the accurate detection and imaging of hot metal component surface, internal defect, is suitable for dynamic defect detection simulation in high temperature extreme environment, and makes up the deficiency that conventional ultrasonic detection method is difficult to realize non-contact high temperature nondestructive testing.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of laser ultrasonic detection, and particularly relates to a hot metal component laser ultrasonic defect detection device and method based on synthetic aperture focusing imaging. BACKGROUND

[0002] With the development of high-end equipment manufacturing fields such as aerospace, marine equipment, and rail transportation towards high precision and high performance, the demand for rapid non-destructive testing of core and key metal component defects is increasing. Rapid detection of defects in hot metal components during high-temperature manufacturing is beneficial to the discovery, repair and inhibition of defects in the early stage of manufacturing, timely processing of components with excessive defects, reducing potential safety risks, and avoiding material and energy waste.

[0003] Currently, non-destructive testing methods that can achieve defect detection in high-temperature environments mainly include machine vision, magnetic powder and penetration detection, eddy current, X-ray, and ultrasonic detection methods. Machine vision, magnetic powder and penetration detection, eddy current, and X-ray methods have certain limitations and cannot solve the problem of internal defect detection. Air-coupled ultrasonic method is suitable for components with small acoustic impedance difference, and electromagnetic ultrasonic method has low detection efficiency and large blind area. Laser ultrasonic detection technology has always been a research hotspot at home and abroad, and has the characteristics of non-contact, high sensitivity, and suitability for complex-shaped component non-destructive testing, and has great potential in solving the problem of rapid non-destructive testing of hot metal component defects.

[0004] In addition, there are many schemes in the prior art that use laser ultrasonic technology to detect defects, but the moving scanning mechanism and laser spot focusing mechanism in high-temperature environments have the problems of complex structure, low scanning range, high cost, and low defect imaging precision. In view of this, in order to improve the defect detection precision in high-temperature environments, it is necessary to provide a hot metal component laser ultrasonic defect detection device and method. SUMMARY

[0005] The purpose of the present application is to provide a hot metal component laser ultrasonic defect detection device and method to overcome the problems in the background art.

[0006] In order to achieve the above object, the application provides a kind of hot metal component laser ultrasonic defect detection device, including high temperature heating module, laser detection module, laser excitation module, mobile scanning automatic focusing module and signal acquisition and control module, the high temperature heating module includes high temperature heating furnace, support seat is equipped in the high temperature heating furnace, detection hole is opened in the side wall of the high temperature heating furnace;The laser detection module includes double-wave mixing interferometer and optical probe, the double-wave mixing interferometer is connected with the optical probe;The laser excitation module includes laser, beam expander, reflector, plano-convex lens and dichroic mirror, the beam expander and the reflector are sequentially arranged in the light path front of the laser, the plano-convex lens is arranged in the light direction of the reflector, the dichroic mirror is arranged in the light direction of the plano-convex lens and the optical probe, and the dichroic light of the dichroic mirror is detected to the metal component to be measured on the support seat through the detection hole;The mobile scanning automatic focusing module includes two parallel guide rails, one end of the two guide rails is respectively provided with a sensor, a sliding block and a screw rod mechanism are arranged on the two guide rails, the two sliding blocks are respectively connected with support plates, and a moving platform and a moving platform driving mechanism are arranged on the support plates;The signal acquisition and control module includes display screen and signal acquisition and control analysis system, and the signal acquisition and control analysis system is respectively connected with the laser, the double-wave mixing interferometer, the sensor, the screw rod mechanism and the moving platform driving mechanism.The structure is set, the reflector can adjust the relative position of excitation incident laser spot and detection laser spot on the surface of the measured metal component, and is suitable for different laser ultrasonic detection methods;Sliding block, moving platform and signal acquisition and control analysis system can realize the automatic focusing function of detection laser simply and quickly, and are suitable for optical probes with different focal lengths, and the set screw can prevent the sliding block from moving forward and backward after reaching the specified focal length position, thereby improving the detection laser sensitivity.

[0007] Further, the aperture of the detection hole is 30mm-50mm, the detection hole is provided with sapphire heat-resistant glass with high light transmittance, and the two ends of the sapphire heat-resistant glass are coated with an anti-reflection coating, which is conducive to the incidence of excitation laser and detection laser on the surface of the measured metal component.

[0008] Further, the laser, the beam expander, the reflector, the plano-convex lens, the dichroic mirror and the optical probe are fixed on the moving platform by bolts, and the input end of the optical probe is connected with a cooling box.

[0009] Further, the screw rod mechanism includes a screw rod and a first servo motor, and the sliding block can slide in the front and back directions of the screw rod under the drive of the motor;The moving platform driving mechanism includes a second servo motor for driving the moving platform to move left and right and a third servo motor for driving the moving platform to move up and down.

[0010] Further, the moving direction of the sliding block and the detecting direction of the optical probe are perpendicular to the side wall plane where the detecting hole is located; and the moving plane of the moving platform is parallel to the side wall plane where the detecting hole is located.

[0011] Further, the stroke of the sliding block is 300mm-500mm; the stroke of the moving platform in the left-right direction is 80mm-120mm; and the lifting height of the moving platform is 0-120mm.

[0012] Further, after the two sliding blocks reach the specified focal length position, the fixing screws on the side of the sliding blocks are tightened to fix the fixing screws and the guide rails, so that relative movement of the device under external disturbance is avoided.

[0013] The application further provides a laser ultrasonic defect detection method for a hot metal component, which adopts the laser ultrasonic defect detection device for a hot metal component.

[0014] S1, a signal acquisition and control analysis system is started, the moving sliding block is controlled to move away from the high-temperature furnace according to the focal length of the optical probe; the furnace door of the high-temperature furnace is opened, and the metal component to be detected is fixed on the support seat in the high-temperature furnace through a clamp;

[0015] S2, the furnace door of the high-temperature furnace is closed, the sliding block is moved through the signal acquisition and control analysis system, and the detection laser receiving signal is observed through a display screen, so that the position of the sliding block is adjusted to obtain the best detection laser sensitivity;

[0016] S3, then, the high-temperature furnace is started, and the high-temperature furnace heats the metal component to be detected according to a set program;

[0017] S4, the laser, the double-wave mixing interferometer and the moving platform are set with various control parameters;

[0018] S5, the laser, the double-wave mixing interferometer, the moving platform and the optical probe are started, so that the laser ultrasonic scanning signal of the metal component to be detected is obtained;

[0019] S6, the ultrasonic scanning signal is processed based on a synthetic aperture focusing imaging algorithm, and finally the imaging diagram of the surface and internal defects of the metal component to be detected is obtained.

[0020] Further, the moving step length of the moving platform ranges from 0.01mm to 10mm, and the scanning range of the metal component to be detected ranges from 0mm 2 to 25mm 2 .

[0021] Compared with the prior art, the present application has the following beneficial effects:

[0022] (1) The laser ultrasonic defect detection device for hot metal components comprises a high-temperature heating module, a laser excitation module, a laser detection module, a mobile scanning automatic focusing module and a signal acquisition and control analysis module. The laser excitation module and the laser detection module excite laser, and the excitation laser and the detection laser are incident to different positions of the measured metal component in the high-temperature heating module through the mobile scanning automatic focusing module. The reflected detection laser is transmitted to the signal acquisition and control analysis module through an optical probe and an interferometer for processing and imaging. The device has the functions of high-temperature heating simulation of metal components, automatic focusing of detection laser, rapid mobile scanning and automatic imaging of defects, and can efficiently realize accurate detection and imaging of surface and internal defects of hot metal components, and is suitable for dynamic defect detection simulation in high-temperature extreme environment, and makes up for the deficiency that the conventional ultrasonic detection method cannot realize non-contact high-temperature nondestructive testing.

[0023] (2) The laser ultrasonic defect detection method for hot metal components is realized through the detection device based on synthetic aperture focusing imaging, solves the problems of low defect detection efficiency and poor defect imaging effect under high temperature, and has great application potential in high-temperature in-situ defect detection in the fields of industry and national defense.

[0024] In addition to the purposes, features and advantages described above, the present application has other purposes, features and advantages. The present application will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0025] The accompanying drawings are used to provide further understanding of the embodiments of the present application, and constitute a part of the specification, and are used to explain the embodiments of the present application together with the following specific embodiments, but do not constitute a limitation on the embodiments of the present application. In the drawings:

[0026] Figure 1 The present application provides a laser ultrasonic defect detection device for hot metal components based on synthetic aperture focusing imaging;

[0027] Figure 2 The scanning schematic diagram of laser excitation and reception for surface defect detection of the embodiments provided by the present application;

[0028] Figure 3 The scanning schematic diagram of laser excitation and reception for internal defect detection of the embodiments provided by the present application;

[0029] Figure 4 The imaging principle diagram of surface defects of the embodiments provided by the present application;

[0030] Figure 5 The imaging principle of internal defects of the embodiments provided by the present application is shown in the figure;

[0031] Figure 6 The flowchart of the laser ultrasonic defect detection method of the hot metal member provided by the present application is shown in the figure;

[0032] In the figure: 1, laser; 2, guide rail; 3, beam expander; 4, support plate; 5, screw rod mechanism; 6, reflecting mirror; 7, plano-convex mirror; 8, dichroic mirror; 9, moving platform; 10, optical probe; 11, set screw; 12, sliding block; 13, optical fiber; 14, double-wave mixing interferometer; 15-1, display screen; 15-2, signal acquisition and control analysis system; 16, metal member to be tested; 17-1, high-temperature heating furnace; 17-2, support seat; 17-3, detection hole; 18, sensor. DETAILED DESCRIPTION

[0033] The present application will be described in detail below with reference to the embodiments shown in the accompanying drawings, but it should be noted that these embodiments are not a limitation on the present application, and equivalent transformations or substitutions of function, method, or structure made by those of ordinary skill in the art based on these embodiments are within the scope of protection of the present application.

[0034] Please refer to Figure 1 The present embodiment provides a laser ultrasonic defect detection device for hot metal members, which comprises a high-temperature heating module, a laser detection module, a laser excitation module, a moving scanning automatic focusing module, and a signal acquisition and control module, and the specific structure is as follows:

[0035] The high-temperature heating module comprises a high-temperature heating furnace 17-1, and the high-temperature heating furnace is provided with a support seat 17-2, the metal member to be tested 16 is fixed on the support seat 17-2 by a clamp, and the sidewall of the high-temperature heating furnace 17-1 is provided with a detection hole 17-3 with a diameter of 30mm~50mm, which is used for transmitting laser and detection laser to the surface of the metal member 16 through the detection hole 17-3. The detection hole 17-3 is provided with a sapphire heat-resistant glass with high light transmittance, and the two ends thereof are coated with an anti-reflection coating, the highest heating temperature of the high-temperature heating furnace 17-1 is 1350℃, and high-temperature heating simulation of various metal members can be realized.

[0036] The laser excitation module comprises a laser 1, a beam expander 3, a mirror 6, a plano-convex mirror 7 and a dichroic mirror 8. The output laser of the laser 1 passes through the beam expander 3, the mirror 6, the plano-convex mirror 7 and the dichroic mirror 8 in sequence and then enters the metal component 16 to be detected through a detection hole 17-3. The laser 1, the beam expander 3, the mirror 6, the plano-convex mirror 7 and the dichroic mirror 8 are fixed on the moving platform 9 of the mobile scanning automatic focusing module by bolts. The laser 1 is a nanosecond pulse laser, the excitation laser wavelength is 532 nm, and the laser pulse width is 8 ns. The beam expander 3 can increase the beam diameter of the excitation laser and reduce the divergence angle. The mirror 6 can adjust the relative position of the excitation incident laser spot and the detection laser spot on the surface of the metal component 16 to be detected. The focal length of the plano-convex mirror 7 is 100 mm to 300 mm. The dichroic mirror 8 has high reflectivity for the laser with a wavelength of 532 nm, thereby realizing the excitation laser incidence function.

[0037] The laser detection module comprises a double-wave mixing interferometer 14 and an optical probe 10. The optical probe 10 is fixed on the moving platform 9 by bolts, and the input end of the optical probe 10 is connected to a cooling box. The double-wave mixing interferometer 14 is connected to the optical probe 10 through an optical fiber 13. The detection laser excited by the optical probe 10 is continuous laser. The focal length of the optical probe 10 is 100 mm to 300 mm. The detection laser excited by the optical probe 10 is incident on the metal component 16 to be detected through the dichroic mirror 8. The detection reflected laser with defect information is received by the optical probe 10 and input into the double-wave mixing interferometer 14 to form interference fringes. The interference fringes are converted into electrical signals by a photodetector, thereby realizing the defect detection function.

[0038] The mobile scanning automatic focusing module comprises two guide rails 2, a sliding block 12, a screw rod mechanism 5, a support plate 4, a sensor 18, a set screw 11 and a mobile platform 9, the two guide rails 2 are arranged in parallel along the Y direction, and one end of each of the two guide rails 2 is provided with a sensor 18, the sensor 18 is used for determining the relative position of the mobile platform 9, and one sliding block 12 and one screw rod mechanism 5 are arranged on each of the two guide rails 2. The mobile platform 9 base is fixed on the support plate 4 through bolts, and the support plate 4 is connected with the sliding blocks 12 on the two guide rails 2 through bolts; the sliding block 12 is provided with a set screw 11 on the side surface, and the set screw 11 is used for fixing the sliding block 12 to prevent vibration during detection. In the structure, the screw rod mechanism 5 comprises a screw rod and a first servo motor, and the sliding block 12 can slide in the front and back directions of the screw rod under the drive of the first servo motor; the mobile platform driving mechanism comprises a second servo motor for driving the mobile platform 9 to move in the left and right directions (X direction) and a third servo motor for driving the mobile platform 9 to move in the up and down directions (Z direction); that is, the mobile platform 9 can move in the left and right directions under the drive of the second servo motor and can rise and fall in the up and down directions under the drive of the third servo motor. The moving direction of the sliding block 12 and the detection direction of the optical probe 10 are both perpendicular to the side wall plane where the detection hole 17-3 is located; the moving plane (X-Z plane) of the mobile platform 9 is parallel to the side wall plane where the detection hole 17-3 is located, and the mobile platform 9, the sliding block 12, the set screw 11 and the sensor 18 can realize the functions of high-temperature rapid mobile scanning, detection and laser automatic focusing. Specifically, the stroke of the sliding block 12 is 300mm~500mm; the stroke of the mobile platform 9 moving left and right is 80mm~120mm, and the lifting height (up and down direction) of the mobile platform 9 is 0~120mm.

[0039] The signal acquisition and control module comprises a display screen 15-1 and a signal acquisition and control analysis system 15-2, the signal acquisition and control analysis system comprises a high-speed acquisition card and a high-performance processor, the signal acquisition and control analysis system 15-2 is connected with the laser 1, the double-wave mixing interferometer 14, the sensor 18, the screw rod mechanism 5 and the mobile platform driving mechanism respectively, the mobile platform 9 is controlled to move in the left and right directions (X direction) and the up and down directions (Z direction), the laser excitation of different energies and the ultrasonic signal acquisition and processing are controlled by the acquisition card and the processor, and the surface and internal defect detection and imaging functions of the measured metal component 16 are realized through the analysis system.

[0040] The embodiment of the present application also provides a laser ultrasonic defect detection method for a hot metal component, which adopts the laser ultrasonic defect detection device for the hot metal component, and the detection method comprises the following steps:

[0041] S1, start the signal acquisition and control analysis system 15-2, control the mobile slider 12 to move away from the high-temperature furnace 17-1 according to the focal length of the optical probe 10; open the furnace door of the high-temperature furnace 17-1, and fix the metal component 16 to be measured on the support seat 17-2 in the high-temperature furnace 17-1 by the clamp.

[0042] S2, close the furnace door of the high-temperature furnace 17-1, move the slider 12 by the signal acquisition and control analysis system 15-2, and observe the detection laser receiving signal through the display screen 15-1 to adjust the position of the slider 12 to obtain the best detection laser sensitivity, so as to realize the automatic focusing function of the high-temperature detection laser; if the surface defects of the metal component 16 to be measured are detected, adjust the reflecting mirror 6 to separate the excitation laser spot and the detection laser spot, as shown in Figure 2 ; if the internal defects of the metal component 16 to be measured are detected, adjust the reflecting mirror 6 to coincide the excitation laser spot and the detection laser spot, as shown in Figure 3 .

[0043] S3, then, start the high-temperature furnace 17-1, and heat the metal component 16 to be measured according to the set program; the heating range of the high-temperature furnace 17-1 is 0℃-1350℃.

[0044] S4, set the control parameters of the laser 1, the double-wave mixing interferometer 14 and the moving platform 9; the excitation laser wavelength of the laser 1 is 532nm; the detection laser wavelength is 1064nm; set the moving step and the total number of movements of the moving platform 9 according to the appearance size and the precision requirement of the metal component 16 to be measured, and the moving step range is 0.01mm-10mm; the scanning range of the measured metal component is 0mm 2 -25mm 2 .

[0045] S5, start the laser 1, the double-wave mixing interferometer 14, the moving platform 9 and the optical probe 10, move the moving platform 9 according to the scanning path as shown in Figure 2 and Figure 3 , excite the ultrasonic wave on the surface of the metal component 16 to be measured by the laser beam of the laser 1, excite the detection laser and receive the reflected laser into the double-wave mixing interferometer 14 by the optical probe 10, obtain the laser ultrasonic scanning signal of the metal component 16 to be measured by the double-wave mixing interferometer 14, and transfer it to the acquisition card and the processor.

[0046] S6, process the ultrasonic scanning signal based on the synthetic aperture focusing imaging algorithm, and finally obtain the imaging diagram of the surface and internal defects of the metal component 16 to be measured; the signal acquisition and control analysis system 15-2 adjusts the position of the slider 12 according to the scanning path as shown in Figure 4The detection principle shown is analyzed and imaged; if the internal defects of the metal component 16 to be tested are detected and synthetic aperture focusing imaging is performed, the signal acquisition and control analysis system 15-2 is based on the following... Figure 5 The detection principle shown is analyzed and imaged through the emission propagation path. and reflection path After obtaining the total propagation time, the amplitude of each scan signal is obtained for imaging, and an image of the surface and internal defects of the metal component 16 under test is obtained and displayed on the display screen 15-1.

[0047] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A laser ultrasonic apparatus for the detection of defects in a hot metal component, characterised in that, The utility model provides a kind of high-temperature heating module, laser detection module, laser excitation module, mobile scanning automatic focusing module and signal acquisition and control module including, the high-temperature heating module includes high-temperature heating furnace (17-1), support seat (17-2) is equipped in the high-temperature heating furnace, detection hole (17-3) is set on the lateral wall of high-temperature heating furnace (17-1);The laser detection module includes double-wave mixing interferometer (14) and optical probe (10), and the double-wave mixing interferometer (14) is connected with the optical probe (10);The laser excitation module includes laser (1), beam expander (3), reflector (6), plano-convex mirror (7) and dichroic mirror (8), and the beam expander (3) and the reflector (6) are sequentially arranged in the light path front of laser (1), and the plano-convex mirror (7) is arranged in the light direction of reflector (6), and the dichroic mirror (8) is arranged in the light direction of plano-convex mirror (7) and optical probe (10), and the dichroic light of dichroic mirror (8) is opposite to the detection hole (17-3) and is detected to the metal component (16) on support seat (17-2);The mobile scanning automatic focusing module includes two parallelly arranged guide rails (2), and one end of the two guide rails (2) is respectively provided with sensor (18), and the two guide rails (2) are all provided with sliding block (12) and screw rod mechanism (5), and the two sliding blocks (12) are respectively connected support plate (4), and the support plate (4) is provided with mobile platform (9) and mobile platform drive mechanism;The signal acquisition and control module includes display screen (15-1) and signal acquisition and control analysis system (15-2), and the signal acquisition and control analysis system (15-2) is connected with laser (1), double-wave mixing interferometer (14), sensor (18), screw rod mechanism (5) and mobile platform drive mechanism respectively;Laser (1), beam expander (3), reflector (6), plano-convex mirror (7), dichroic mirror (8) and optical probe (10) are fixed on the mobile platform (9) by bolt.

2. The apparatus of claim 1, wherein, The aperture of the detection hole (17-3) is 30mm-50mm, the detection hole (17-3) is provided with sapphire heat-resistant glass with high light transmittance, and the both ends of the sapphire heat-resistant glass are coated with an anti-reflection coating.

3. The apparatus of claim 1, wherein, The input end of the optical probe (10) is connected to a cooling box.

4. The apparatus of claim 1, wherein, The screw rod mechanism (5) includes a screw rod and a first servo motor, and the sliding block (12) can slide along the front and back directions of the screw rod under the drive of the motor.

5. The apparatus of claim 4, wherein, The moving direction of the sliding block (12) and the detection direction of the optical probe (10) are both perpendicular to the side wall plane where the detection hole (17-3) is located. The moving plane of the mobile platform (9) is parallel to the side wall plane where the detection hole (17-3) is located.

6. The apparatus of claim 4, wherein, The stroke of the slider (12) is 300mm-500mm; the stroke of the moving platform (9) in the left-right direction is 80mm-120mm, and the lifting height of the moving platform (9) is 0-120mm.

7. The apparatus of claim 1, wherein, After the two sliders (12) reach the specified focal length position, the clamping screw (11) is fixed with the guide rail (2) by tightening the clamping screw (11) on the side of the slider (12).

8. A method of laser ultrasonic defect detection of a hot metal component, characterized in that The laser ultrasonic defect detection device for hot metal components comprises a laser ultrasonic signal acquisition and control analysis system (15-2), a high-temperature heating furnace (17-1), a moving slider (12), a moving platform (9), a double-wave mixing interferometer (14), a laser (1), and an optical probe (10). S1, start the signal acquisition and control analysis system (15-2), control the moving slider (12) to move away from the high-temperature heating furnace (17-1) according to the focal length of the optical probe (10); open the door of the high-temperature heating furnace (17-1), and fix the to-be-detected metal component (16) on the support seat (17-2) in the high-temperature heating furnace (17-1) by a clamp; S2, close the door of the high-temperature heating furnace (17-1), move the slider (12) by the signal acquisition and control analysis system (15-2), and observe the detection laser receiving signal through the display screen (15-1) to adjust the position of the slider (12) to obtain the best detection laser sensitivity; S3, then, start the high-temperature heating furnace (17-1), and the high-temperature heating furnace (17-1) heats the to-be-detected metal component (16) according to a set program; S4, set various control parameters of the laser (1), the double-wave mixing interferometer (14), and the moving platform (9); S5, start the laser (1), the double-wave mixing interferometer (14), the moving platform (9), and the optical probe (10) to obtain the laser ultrasonic scanning signal of the to-be-detected metal component (16); S6, process the ultrasonic scanning signal based on a synthetic aperture focusing imaging algorithm to finally obtain the imaging diagram of the surface and internal defects of the to-be-detected metal component (16).

9. The method of laser ultrasonic defect detection of a hot metal component according to claim 8, characterized in that, The moving step length of the moving platform (9) ranges from 0.01 mm to 10 mm, and the scanning range of the metal component (16) to be measured ranges from 0 mm 2 ~25 mm 2 .

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