Research On The Infrared Temperature Measurement Technology For Large Forgings Based On Three-level Filter

Large forgings are the key parts of the large equipments. With the advances ofmodern industrial technology, rapid development has been made in the electricity,shipping, nuclear power, energy and chemical industry. And the higher quality of largeforgings is required. So acquiring and controlling the temperature accurately during theforging process is vitally important. However, there are many constraints factors thataffect the accuracy of the current temperature measurement method. The constraint factorsinclude the emissivity, the high temperature background radiation, the oxide skin coverage,the stray light and so on. Therefore, it has a large measurement error, and it is difficult toreach the temperature measurement requirements. In this paper, a new online infraredtemperature measurement method is proposed based on three-level interference filter. Thismethod is on the basis of the existing infrared temperature measurement system. The maincontents as follows:Firstly, the basic principle of infrared radiation and infrared thermometry areresearched. Then a new infrared temperature measurement method is proposed in thepaper. This method is proposed on the basis of the existing infrared temperaturemeasurement system. It is applied in the on-line temperature measurement of the largehigh-temperature forging’s production process.Secondly, a new infrared temperature measurement system is built in this paper. Thissystem is on the basis of the before-mentioned temperature measurement method. Athree-level interference filter system is proposed. The performance and the parameters ofthe filter system are researched and simulated. Considering the existence of the oxide skinin the high-temperature forgings’ surface, the heat transfer process between the oxide skinand the high-temperature forgings is further studied. Then a heat transfer model betweenthe oxide skin and the high-temperature forgings is established. A new algorithm isdeduced according to the heat transfer theory. The new algorithm is used to measure thereal temperature of the high-temperature forgings’ surface. And the high-temperatureforgings are covered with the oxide skin. Finally, the experimental study of the temperature measurement for thehigh-temperature forgings is carried on in the laboratory. And the experimental study usedthe infrared temperature measurement method proposed in this paper. The feasibility ofthe temperature measurement method is verified through the analysis of the experimentalresults.