An unsteady temperature field measurement method for large hot cylindrical shell forging based on infrared spectrum

At present, measuring the temperature field of large hot cylindrical shell forging in real time remains a longstanding challenge in forging process. Aiming at the issue, an unsteady temperature field measurement method is proposed based on infrared spectrum in this paper. Firstly, combining the principle of primary spectrum pyrometry and three-stage Fabry-Perot cavity liquid crystal tunable filter (LCTF), an infrared temperature measurement system is devised to detect the surface temperature field of large hot cylindrical shell forging. Secondly, a two-dimensional unsteady heat transfer model of the forging is established. On the basis of the model and the obtained surface temperature field, the interior temperature field is acquired. Meanwhile, the new surface temperature field is continuously collected by the devised system. By repeating the above processes, the temperature field measurement of large hot cylindrical shell forging can be achieved. A clear advantage of the proposed method is that the whole temperature field real-time measurement can be achieved without knowing the value of the surface emissivity beforehand. Moreover, the influence of background light radiation on the measurement result is effectively inhibited. Finally, the feasibility of the method is proved by the experimental results. The method provides a new approach to temperature field measurement of hot cylindrical shell forging.