Research And Application Of Surface Defect Detection Method Based On Eddy Current Effect

Metal slewing bodies are widely used in many fields such as construction,automobile companies,aerospace,water conservancy,etc.,but they are very prone to defects during production or use,which affects the economic benefits of the enterprise and the safety of the users.In order to discover the defects of the metal rotating body in time,the metal rotating body must be regularly tested for defects.The testing equipment used by domestic enterprises is mainly introduced,which increases the cost of testing.In order to realize the detection of the surface defects of the metal rotating body,this subject systematically studies the eddy current defect detection technology,and develops a simple and practical defect detection system,which can meet the needs of detecting defects such as surface cracks of the metal rotating body.The detection system is based on eddy current sensors,angle sensors,data acquisition cards,etc.,combined with self-developed detection programs and designed automation platforms.The detection device is easy to use and simple to operate,and can accurately detect metal slewing bodies Defect locations on and near the surface.The eddy current detection signal is susceptible to other factors.This paper uses the characteristics of different excitation frequencies,lift-off,detection speed and other factors to the sensitivity of the output signal.Through the experimental research on the surface defect detection parameters of the metal rotating body,the best working parameter combination is finally determined to improve the accuracy of the detection results And reliability.This article mainly completes the following work:(1)Explain the working principle of eddy current metal surface defect detection,analyze the various factors that affect the effect of eddy current metal surface defect detection,and give the algorithm and implementation idea of determining the position of the surface defect of the rotating part from the angle signal and the displacement signal,The best working parameter combination is proposed.(2)Based on the analysis of the characteristics of the problem and the actual needs on site,the overall scheme of the detection device is proposed and the engineering design andproduction are completed.The detection device includes two parts: hardware and software.Through the reasonable combination of these two parts,the purpose of locating the surface defects of the metal rotating body is achieved.(3)Completed the design,calculation and selection of related components of the inspection system.Appropriate eddy current sensors,appropriate angle sensors,data acquisition cards and other related equipment were customized,and the installation,commissioning and use experiments of the detection device were completed.(4)The overall planning of the software system's functions and implementation plan,using labview programming,completed the design and development of the detection device software system;realized the real-time waveform display of the eddy current sensor and angle sensor signal;equipped with automatic detection of the detected defect signal Alarm,display,record and other functions,can also save the required data information and other operations.(5)The relationship between the detection frequency,lift-off,detection speed and output signal is studied,and the range of the best detection parameters is obtained,which improves the accuracy of subsequent defect detection.The experimental results prove that the detection system has strong stability,can accurately detect the specific location of the defect,and can also identify the defect type according to the specific detection result and predict the crack depth.These studies provide a theoretical basis for the detection system design and crack size quantification.