Ultrasonic Impact Treatment Effect on Lcr Wave Acoustoelastic Coefficient for Stress Evaluation of Low Carbon Steel

Surface stress is very important for the performances of metals, but there is still no one suitable method for forecasting surface stress as needed, so a combined method including ultrasonic impact treatment (UIT) and critically refracted longitudinal (Lcr) wave was proposed. Based on that reason, the influence of repetition rate of UIT on Lcr wave acoustoelastic coefficient was discussed in this study. The Lcr waves of Q235 steel under different values of stress were collected by using Lcr wave experimental system, and then the difference in time of flight between Lcr waves was calculated based on the cross correlation theory, at last the relationship between Lcr wave acoustoelastic coefficient and repetition rate of UIT was discussed. Results show that although repetition rates of UIT are different, the relationship between difference in time of flight and stress is well agreed with the Lcr wave acoustoelastic theory. As repetition rate of UIT increases, Lcr wave acoustoelastic coefficient becomes higher gradually, until repetition rate of UIT is reached 600