Testing at high temperatures

In many industrial applications of the properties of ultrasonic waves the material or object under examination is generally at or near ambient temperature, which is convenient and acceptable for ultrasonic transmission by means of piezoelectric devices. If, however, the material is at higher temperatures the transmission of ultrasonic signals becomes problematical. It is indicated how the development of ultrasonic testing at high-temperature would benefit the steel industry. Attention is given to some basic physical factors relating to high temperature testing, possibilities for the practical realization of the inspection of hot steel, the application of ultrasonics to the solidification of metals, and the possibility of temperature measurement by ultrasonics.