Research On Flaw Localization Algorithm For Axle Ultrasonic Inspection System

Solid axle railway testing is usually used by a single probe-based manual testing method, however, both the efficiency and the accuracy rate of detection are low. With the rapid development of the high-speed railway of the world, the phased array ultrasonic testing method is presented in the paper to make up for a single probe manual testing methods shortcomings and deficiencies in the analysis of the axle defect causes, types, and the stress concentration region.Currently, some developed countries have designed and established their own advanced axle inspection system. In our country, an axle ultrasonic inspection system is researched and developed independently, which is based on phased array ultrasonic technology and general ultrasonic technology. The system can detect all area of the axle, and defect various types of fatigue flaws and material flaws. However, defects are positioned by means of dragging frame manually. It’s inevitable for bringing some human operative errors and confining the efficiency of defects testing.In this paper, on the premise of investigating and summarizing axle testing technology and devices at home and abroad, combining with analysis of China railway axle’s structural characteristics and phased array ultrasonic technology, the features of defects and interferences are extracted, and a set of defects localization algorithms are proposed based on image enhancement, method of level projection, Column subtracting pixels of each line and more parameters comparison of connected region. By using these methods, flaws in the testing image can be positioned accurately, and the pre-setting testing effect is achieved. At last, by using the method of endpoint value6dB calculate the length of the defects, and make the error analysis. At last, a field application implementation of localization algorithm is proposed here, and some guidelines for the work afterward are given.