A novel approach to the realisation of a rail specimen with defined surface cracks in work-hardening manganese steel for the calibration of inductive thermographic measurements

Induction thermography is a well-established method for the detection of surface defects in magnetic steel. Furthermore, static inductive measurements are used to estimate the depths and penetration angles of surface cracks. This work presents a new approach to creating crack-like, but defined surface defects in a manganese steel rail specimen. Cuts with different penetration depths and angles are introduced into the head of the rail via wire erosion. The work-hardening behaviour of manganese steel allows for the cuts being closed by subsequent roll-overs performed on a full-scale wheel-rail test rig. This improves the calibration of the parameters used for the specification of crack depth and penetration angle during measurements of rolling contact fatigue damage in track.