基于A型脉冲反射式超声技术的转辙机缺陷检测研究

Research on Defect Detection of Railway Switch Machine Based on A⁃Type Pulse Reflection Ultrasonic Testing Technology

随着我国铁路行业的快速发展,铁道部电务系统对道岔转辙机零部件的检测要求越来越高。目前,转辙机关键部件检测主要依靠人工目视检测,存在漏检风险。因此,提出了一种基于A型脉冲反射式超声探伤技术的裂纹定量检测方法。首先,分析了金属材料力学性能,计算了道岔转辙机关键部件的临界裂纹理论长度,并以此为基础在与转辙机关键部件相同材料的试件上设计了刻槽缺陷模拟实际裂纹。然后,基于无损检测专业仿真平台CIVA建立了试件模型,采用A型脉冲反射式单晶直探头对试件进行检测,分析声场特点并选取最优探头参数。最后,搭建了实验平台,通过对A扫信号的分析处理获得了试件截面图,重构缺陷位置相对误差小于2%,验证了该方法的可行性。该检测方法具有成本低、精度高的优点,为解决转辙机关键部件的缺陷检测提供参考。

With the rapid development of China's railway industry,the Ministry of Railways electrical system has increasingly higher requirements for the inspection of key components of switch machine.At present,the inspection of key parts of the switch machine mainly relies on manual visual inspection which will be accompa⁃nied by a risk of missed inspection.Therefore,a crack quantitative detection method based on A⁃type pulse re⁃flection ultrasonic flaw detection technology is proposed.Firstly,the mechanical properties of metal materials are analyzed,and the theoretical critical crack length of the key components of the switch machine is calculat⁃ed.Based on this,the notch defects are designed to simulate actual cracks on the test piece of the same materi⁃al as the key components of the switch machine.Then,based on the nondestructive testing professional simula⁃tion platform CIVA,a specimen model is established,and the specimen is tested with an A⁃type pulse reflective single crystal straight probe,the characteristics of the sound field are analyzed,and the optimal probe parame⁃ters are selected.Finally,an experimental platform is built,and the cross⁃sectional view of the specimen is ob⁃tained through the analysis and processing of the A⁃scan signal.The relative error of the reconstructed defect position is less than 2%,which verifies the feasibility of the method.The detection method has the advantages of low cost and high accuracy,and a reference for solving the defect detection of key components of the switch machine is provided.