Ultrasonic stress evaluation on welded plates with Lcr wave

The acoustical theory is introduced. Ultrasonic stress measurement experimental installation is established, consisted of a variable angle transducer and an oscillograph with special higher digitiser board. Acoustoelastic coefficient of longitudinal critically refracted waves propagating in Q-235 steel is calibrated by the tensile testing machine. In the present paper are discussed the longitudinal stress and transverse stress on twin wire welded plate, and a comparison is made with the result of finite element method obtained by Marc Software. The present paper also discusses the longitudinal stress distributions of multilayer welded plate and longitudinal residual stress gradient of 2219 Al alloy is obtained in the ultrasonic travel time change expression formal. Instability acoustoelasticity effect in elastic region of welding residual stress field is discovered. The sources of measurement error are pointed out. In conclusion the potential of the ultrasonic method in different industrial cases is particularised.