Microstructure effect of weld joint heat affected zone on the temperature velocity factor of ultrasound

The effect of temperature on the longitudinal wave speed in the heat-affected zone of the weld joint of structural steel 20 is investigated. The heat-affected zone is the most dangerous place where the stress-strain state is realized and a gradient of physical and mechanical properties is observed. As a rule, it is in the heat-affected zone that the structures are destroyed. The structural state of the heat-affected zone has a significant effect on the temperature dependence of the elastic wave velocity. As a result of the research, numerical values of the temperature-velocity factor for longitudinal ultrasonic waves in steel 20 for the heat-affected zone and the base metal were obtained. In the future, the dependencies can be used to develop methods for determining material damage by the ultrasonic method.