| With the rapid development of social economy,high-speed and heavy-load railway has become the main direction for China's railway development.The quality of rails will directly affect the speed and safety of trains.In order to ensure the internal quality and safety of rails,the state clearly requires that the rails must be inspected by ultrasonic inspection and be qualified before leaving the factory.Pangang Group Company had introduced a rail-line ultrasonic flaw detector from Kraut Kramer Germany more than a decade ago and had successfully applied to rail production sites.However,with the improvement of rail technical standards and the increase in the number of different types,this ultrasonic flaw detection device now can not fully meet the users' special requirements for rail flaw detection and the requirements for asymmetrical rail detection.At the same time,due to the high maintenance cost and the fact that some components are not available for replacement,it is necessary to redesign a set of ultrasonic on-line detection automatic control system that adapts to the actual conditions of Pangang Group Company to achieve the goal of inspecting different types of steel rails with different specifications and also reduce production costs but increase production capacity.This thesis is based on the basic principles of ultrasonic flaw detection technology and national rail testing standards,As well as high flaw detection area,multi-species adaptability of rail testing needs,proposes an overall design scheme for the ultrasonic automatic detection system for rails and specifies the flaw detection method,coupling method,probe layout,probe equipment and Mechanical design ideas.The design scheme includes two aspects,a flaw detection device composed of a probe,a landing gear and a guide device,and a multi-channel ultrasonic flaw detector and a flaw detection device composed of a flaw detection and control system.In terms of flaw detection devices,ultrasonic inspection probes,landing gear devices and guide devices that meet the requirements of different types of specifications are designed for the detection area required for the rail head,rail lumbar and rail foot respectively.Multi-channel rail ultrasonic flaw detector will be based on FPGA FIR digital filter front,through the PCI-E bus for data acquisition,and use of computer real-time data analysis,instead of the original analog ultrasonic flaw detector.The flaw detection and control system is composed of an independent automatic control system and a detection system,which realizes the functions of rail transportation,landing gear control,and processing,acquisition,analysis,defect evaluation and positioning of detection signals.The whole control system is close to the site production,easy to operate,simple and convenient.It can perform ultrasonic flaw detection for different types of rails with different specifications and can satisfy different customers' requirements.The system is stable and reliable with flexibly commissioning mechanism.Its stability of the rail flaw detection process and reproducibility of the test results all meet the production needs;in the mean time it almost achieve the design requirements with the flexible parameter settings in the flaw detection software system. |
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