Effect of Expanding of Internal Stress Cracks in Steel 5140 on Result of Ultrasonic Testing

The differences of the results of the ultrasonic testing in the different time had been analyzed for the steel 5140 which were produced by rolling of continuous casting billet. It was obtained that the effects of the stress cracks expanding in the steel 5140 on results of the ultrasonic testing were obvious. The methods of solving the problem have been provided in the same time.