Abstract: The nondestructive, real-time and high precision detection of internal temperature field in a structure is one of the most important problems in the engineering and scientific experiments, an equipment of noncontact thermometry by electromagnetic acoustic technology is presented. Based on temperature dependence of acoustic velocity propagating through heated materials, internal temperature field can be detected by the sensitivity method. Calibration, steady state and transient state experiments are referred to validate the feasibility and reliability of the presented method. Results reveal that internal temperature gradient and its variation estimated by the method combined electromagnetic ultrasonic and sensitivity method agree well with the measured values using thermocouples installed in the steel, which can be helpful for various fields of science and engineering.

Key words: electromagnetic ultrasonic, equipment of nondestructive thermometry, internal temperature fields, sensitivity method, ultrasonic thermometry