Ultrasonic detection of heat fronts in continuously cast steel product

Measurement of process parameters of continuously cast hot steel can play an important role in assessing the state of the casting process. One quantity of crucial importance is temperature, currently restricted to surface measurements using conventional optical pyrometers. A more useful quantity is internal temperature, and the authors discuss the application of ultrasonic time-of-flight methods to the harsh conditions of a continuous caster, together with some new results. The techniques employed involve electromagnetic acoustic transducers (EMATs) which allow noncontact operation, essential for applications where the product is moving and can have a surface temperature in excess of 1000°C. Data from tests performed at a production caster are presented