Research On The Ultrasonic Testing System Of Axle Billet On High Speed Rail

As the fastest growing country in the construction and development of high speed railway,China is the one of the fullest system technology,highest integration capability,longest operation distance,highest operation speed and largest scale of construction.With the rapid increase of speed,the requirement of machining quality is also raised.However,low degree of the automation of ultrasonic testing is one of the main obstacles for mass autonomous production.At present,ultrasonic testing is mainly conducted under two methods in the production sites.One is by using the portable ultrasonic flaw detector to complete detecting process mannually.Steel billet is coated with coupler on the surface while ultrasonic probe move on it under manual control.At the same time,detecting wave is displayed on the monitor,which is used for defect estimation combining the experience of skilled workers.Great labor indensity,hostile working environment and dependence on proficiency of workers can all affect the result of flaw detection.The other method take large-scale automatic detection equipment to drive the movement of the tested material in order to finish the surface scanning by the rotation or translation of ultrasonic probe relative to the surface of tested material.Device software is capable of filter analysis and defect estimation.Nevertheless,enormous size and high cost prevent such devices from scaling up.To meet the demand of the flaw detection of high speed rail axle,this thesis develops a automatic flaw detecting system based on ultrasonic means.With the controlling software and automatic defect estimation algorithm,the whole detecting process reaches high efficiency and intellegence.The general detecting scheme is developed on the account of the demand analysis of high speed rail axle.Considering the technological characteristics of ultrasonic detecting,the mechanical structure of the mobile flaw detection paltform is established and the prototype is developed.STM32F103ZET6 microprocessor is selected as the core of slave system for controlling,on the basis of which the peripheral circuit is designed for building the hardware structure.With the development of the software of slave controlling system,the communication interface of the host computer and slave system is built and tested.According to the requirement of movement controlling and data processing,the host computer software is designed for giving movement instructions and scanning regularity specified by user to the slave system.Moreover,with the detecting data acquired by PCI data acuisition card,this software displays the detecting wave in A figure,B figure and C figure respectively as well as finishes analysis of spectrum and defect estimation in the light of the characteristics of the flaw wave.Finally,the “distance-amplitude” curve is used as a standard to evaluate the defect in both quantity and quality.To solve the problems of complicated operation and high cost in ultrasonic testing devices,this thesis provides a new detecting system with compact device,comprehensive function and high automation level,which can bring much more economic benetits by reducing labor indensity and cost.