Development On Ultrasonic Automatic Testing System For Flaws Of Rotary Parts Used In Coal Mine Machinery

Rotary parts is widely used in coal mine machinery, and its quality directly affects the safe operation of coal mine equipments. Ultrasonic testing is an important nondestructive testing method, which is applied to control the quality of industry product and monitor the safety of equipment in service widely. At present, the rotary parts is commonly tested manually. However, it has some defects of low efficiency, undetected and inaccurate test results. So it's of great significance to develop an ultrasonic automatic test system.Taking the idea of system integration as guidance, the digital ultrasonic flaw detector as base, an ultrasonic automatic testing system has been developed in this paper, with aid of technologies of mechatronics, ultrasonic imaging and virtual instrument. It has implemented numeralization, automatization and imaging of ultrasonic testing, and it has the performances of displaying ultrasonic A, B, C, D and P-scan imaging, processing and saving data, flaw location and so on.According to test parameters, the automatic scanning device and control system can plan scanning path automatically, and scan the workpiece rapidly and comprehensively. The floating probe gripper is designed, which makes sure good contact between probe and workpiece.The principle and method of ultrasonic scan imaging for angle probe have been studied, and the key technique problems of software implementation of ultrasonic scan imaging have been achieved. Searching pixel unit according to the incident direction of ultrasound, by using linear interpolation algorithm to correct non-isotropic resolution images to isotropic ones, and the readability of B-scan image is improved., D-scan and P-scan image are achieved based on the B-scan image.Ultrasonic automatic testing software of rotary parts has been developed by LabWindows/CVI, making use of multi-threading technology to ensure the reliability of the motion, real-time data acquisition and rapid image generation. It realizes off-line analysis and image reconstruction through saving of ultrasonic data, and replays the A scan waveform and echo amplitude of each detection position. It has the function of multi-layer C-scan, multi-cross-section B-scan and D-scan image. Through de-noising to ultrasonic signal, electromagnetic interference and impact of point noise are eliminated effectively, the reliability and accuracy of flaw localization and quantification are greatly improved.