Ultrasonic Measurement of Residual Stress in the Rims of Inductively Heated Railroad Wheels

摘要

Residual stresses in railroad wheels may change from compressive to tensile during use, a potentially hazardous condition that could cause wheel failure. Until recently, US regulation called for the measurement of a discoloration, revealing past heating that sometimes leads to unsafe stress. Quantitative measurement by ultrasonic methods is an attractive alternative. Stress causes small changes in sound velocity. This report covers an extensive series of ultrasonic tests on ten cast steel wheels; two were as-manufactured, while the others received induction heating to generate stresses similar to in service wheels. Measurements with two different ul-trasonic instruments gave comparable results. Furthermore, ultrasonic measurements correlated well with a simple destructive evaluation. This suggests a useful method for inspection and maintenance.