Abstract
An effective ultrasonic method for measuring the internal temperature distribution of heated materials is presented. The principle of the method is based on temperature dependence of the velocity of the ultrasonic wave propagating through the material. An inverse analysis method coupled with a finite difference model is employed to determine one-dimensional temperature distribution in a heated plate. To improve the accuracy in the determination, the relation between the temperature and the velocity is approximated by a quadratic function. A steel plate of 30 mm thickness is heated by contacting with a heater of 200℃ and subsequently cooled down by water. The ultrasonic measurements are performed for the steel during the heating and cooling. The internal temperature distribution and its transit variation determined ultrasonically agree well with those obtained using thermocouples installed in the steel.
