Y. Javadi, V. Plevris and M.A. Najafabadi, "Using L_CR Ultrasonic Method to Evaluate Residual Stressin Dissimilar Welded Pipes", International Journal of Innovation, Management and Technology, 4(1), pp. 170-174, 2013.

Abstract:
The ultrasonic residual stresses measurement is based on the acoustoelastic effect that refers to the change in velocity of the elastic waves when propagating in a stressed media. The experimental method using the longitudinal critically refracted (L_CR) waves requires an acoustoelastic calibration and an accuracy measurement of the time-of-flight on both stressed and unstressed media. This paper evaluates welding residual stresses in dissimilar pipe-pipe joint of AISI stainless steel 304 and Carbon Steel A106-B type. The residual stresses in inner and outer surface of pipes were evaluated by L_CR ultrasonic waves by using 1Mhz, 2Mhz, 4Mhz and 5Mhz transducers. It has been shown that the difference in residual stresses between inner and outer surfaces of pipes and also between Stainless steel and Carbon Steel side can be inspected by L_CR waves.

Keywords:
Ultrasonic stress Measurement; acoustoelastic effect; welding residual stress; L_CR; dissimilar welded joint.