01

Description

Wheel stress is a key safety issue in the railway sector. Successive braking cycles applied to the wheels change the circumferential stress state from compressive to purely tensile. These tractive stresses can be extremely dangerous in the case of small tread cracks, as they can induce crack growth and eventually lead to catastrophic wheel failure.

02

Challenge

The measurement of the residual stress (RS) of railway wheels is essential for safety reasons. According to the UNE-EN 13262 standard, residual stress measurement methods should estimate the variation of circumferential stress located deep under the running surface and are determined by an ultrasonic velocity measurement method.

03

Solution

The solution is a machine capable of measuring RS in railway wheels in a fully automatic way using the UT-EMAT method. The RS is measured using two electromagnetic acoustic transducers with transmitter and receiver functions to generate linearly polarised cutting waves. Automatic diagnosis provides a direct pass/fail result, reducing cycle time by 50%.