A Temperature Field Measurement Method For Large Hot Cylindrical Shell Forging Based On Infrared Spectrum

Large cylindrical shell forgings are critical components in many significant nationalenergy security fields such as nuclear power industry and petrified industry. The quality oflarge cylindrical shell forgings is directly related with the security of national energy andpeople’s lives. Therefore, production ability of high quality products reflects nationaleconomic and technological development levels. During forging process, the real-time andaccurate measurement of temperature field, especially the interior temperature field, is aneffective means to ensure the right carrying out of forging processes. At present,measuring the temperature field of large hot cylindrical shell forging in real time remains alongstanding challenge in forging process. Aiming at the issue, an unsteady temperaturefield measurement method is proposed based on infrared spectrum in this paper. The maincontents are represented as follows:Firstly, studies surrounding the theory of infrared temperature measurement arecarried out. By combining infrared thermometry and the principle of primary spectrumpyrometry, a new temperature field measurement method for large hot cylindrical shellforging is proposed to reduce the dependence on emissivity in temperature measurementtheory. The research lays a solid theoretical and practical foundation for the on-lineunsteady temperature field measurement of large hot cylindrical shell forging.Secondly, an unsteady heat transfer model of the forging is established according tothe heat transfer of large cylindrical shell forgings. On the basis of the model and theobtained surface temperature field, the interior temperature field is acquired. This changesthe long-term situation: the interior temperature field can’t be acquired through infraredthermometry.Thirdly, the theories of FP-cavity liquid crystal tunable filter (LCTF) are studied. Onthe basis of that, three-stage FP-cavity LCTF is designed to inhibit the influence ofbackground light radiation on the measurement result effectively. Then, a new infraredtemperature measurement system is constructed based on it. The system can meet practicalrequirements. Finally, using MATLAB software, the rationality of the design parameters is verifiedthrough the analysis of spectral transmittance curves. Then, the corresponding experimentsare designed and carried on in the laboratory. And the temperature field is measured byusing the infrared temperature measurement method proposed in this paper. Experimentalresults indicate that the temperature measurement method is effective and feasible.