Quantitative evaluation of damage evolution in austenitic cast manganese steel crossings using acoustic emission

M Kongpuang¹, R Culwick¹, A Marsh¹, V L Jantara Junior¹, P Vallely^{1, 2}, M Papaelias¹ and S Kaenwunruen³
¹School of Metallurgy and Materials, The University of Birmingham, Birmingham, UK Email: mxk763@student.bham.ac.uk
²Network Rail, Baskerville House, Birmingham, UK
³School of Engineering, The University of Birmingham, Birmingham, UK

Crossings represent a railway track discontinuity since train wheels need to change from one rail to the other. Crossings are critical railway infrastructure components subjected to high stresses due to wheel impact loading. The cast manganese steel alloy from which crossings are manufactured makes inspection using conventional ultrasonic methods particularly challenging due to the high attenuation caused by the large austenite grains. Austenitic cast manganese steel is preferred due to its high impact resistance; however, quantitative non-destructive evaluation is practically impossible and hence maintenance is largely based on empirical assumptions. Standard bending fatigue samples were extracted from a cast manganese steel plate. The samples were exposed to cyclic three-point flexural loads until final failure. During fatigue testing crack growth was monitored using direct current potential drop (DCPD) and acoustic emission testing. This study presents the approach used for quantifying damage evolution occurring due to fatigue using the acoustic emission data obtained.

Keywords: railway, cast manganese steel, advanced NDT, remote condition monitoring, acoustic emission, rolling contact fatigue.