Nondestructive Evaluation of Residual Stress in Railroad Wheel Rim with EMATs

Abstract

Compressive hoop residual stress in the rim of a new wheel prevents cracks from emerging on the wheel. But heat impacts in the course of braking operations decrease compressive hoop residual stress in the rim and develop tension hoop stress. As the result, cracks in the rim are growing and lead the wheel to failure. So the development of a nondestructive measurement tool of residual stress and its practical use for the maintenance field of railroad wheel are highly expected to prevent a wheel failure. From this view point we developed the instrument with EMAT for measurement of residual stress of railroad wheel using acoustoelastic effect.
At first, this paper describes the principle of acoustoelastic effect and EMAT, after that, explain about the content of this instrument. Finally, we will discuss about the experimental result using this instrument.