Study on non-destructive testing of rail rolling contact fatigue crack based on magnetic barkhausen noise

Rail rolling contact fatigue (RCF) crack and other rail damage have great impact on the normal operation of the railway system. The detection and evaluation of RCF crack can effectively ensure the running safety of the train. Compared with the traditional non-destructive testing methods, the characteristics of Magnetic Barkhausen Noise (MBN) detection technology such as easier implementation, higher efficiency and faster inspection process etc., make it an ideal choice for non-destructive detection technology of rail RCF crack. Therefore, this paper studied the influence of plastic deformation layer and crack of rail roller on MBN signal. The detection equipment based on MBN signal was built and used to detect and characterize the rail PDL and cracks. The wheel-rail rolling-sliding tests were conducted on a twin-disc tribometer to prefabricate the rail RCF crack and PDL. Experimental results proved that MBN signal decreased with the increase in plastic deformation layer (PDL) thickness. Crack initiation would release the residual compressive stress (RCS) of material surface, resulting in the abnormal increase in MBN signal under the general trend of gradually weakening. The influence mechanism of cracks on MBN signals was analyzed and discussed.