Crack detection in press fit railway axle using induced current focusing potential drop technique

Railway wheelsets are one of the most important components in railway vehicles with regard to safety. Since failure in railway vehicle wheelsets can cause a disaster, regular inspection of cracks in axles and wheels is mandatory. Fatigue cracks were initiated in press fit parts that suffer from fretting fatigue damage, such as the wheel seat, gear seat and brake disc seat. Railway axles in service are regularly checked by ultrasonic testing and magnetic particles inspection. However, due to noise echoes it is difficult to detect crack initiation clearly with ultrasonic testing. Therefore, it is necessary to develop a non-destructive technique that is superior to conventional NDT techniques in order to ensure the safety of high-speed wheelset. The induced current focusing potential drop (ICFPD) technique is a new non-destructive testing technique that can detect cracks in railway axles by applying on electro-magnetic field and potential measurement. In the present paper, the new concept ICFPD technique is applied to the detection in press fit crack of railway axles. To detect the crack, the pick-up pins must be located in the horizontal direction to the crack although it is general that the pick-up pins of potential drop are located in the vertical direction of crack. The crack detections in press fit railway axle by using ICFPD was carried out in the axial and azimuthally direction. The result show that the crack in press fit part could be detected by using this method at 10mm away from the crack. The ICFPD method is useful to detect the crack that initiated in the press fit railway axles.