Inductive Thermography as Non-Destructive Testing for Railway Rails

Inductive thermography is a non-destructive testing method, whereby the specimen slightly heated with short heating pulse (0.1–1 s) and temperature change on surface recorded an infrared (IR) camera. Eddy current induced by means of high frequency (HF) magnetic field in ‘skin’ specimen. Since cracks disturb eddy distribution heat diffusion, they become visible IR images. Head checks squats are specific types damage railway rails related to rolling contact fatigue (RCF). can be excellently used detect head rails, method also applicable for characterizing individual as well crack networks. Several rail pieces checks, artificial electrical discharge-machining (EDM)-cuts squat defect were inspected using inductive thermography. Aiming towards inspection track, 1 m long two different ways: first via ‘stop-and-go’ technique, through which their subsequent images merged together into panorama image, secondly scanning during continuous movement rail. The advantages disadvantages both methods compared analyzed. Special image processing tools developed automatically fully characterize defects (average angle, distance between average length) Additionally, finite element simulations investigate effect measurement setup parameters, order optimize experiments.