The Industrial Applications Of The Colorimetric Temperature Measurement Used In Billet Heating Furnace

Nowadays, with countries all over the world strengthen their economic construction, the demand for steel is rising, and come to the rapid development of metallurgy industry. Only metallurgy industry in China, there exists more than a thousand furnaces of different types, more than seventeen million tons of standard coal were used in it each year. The furnace is an essential equipment in the production of rolling, and also a major energy consuming equipment. So real-time monitoring and forecasting the slab temperature in the furnace is important for the protection of safety, enhance production efficiency, steel product’s quality and energy conservation.Currently, the way of the billet’s internal temperature measured inside the furnace are based on the atmosphere temperature measured by thermocouple, combined with the empirical formula derived surface temperature, and through further simulation of heat conduction knowledge. However, in the actual process, due to a variety of environmental factors and fuel calorific value fluctuations and other factors exist error. Therefore, to obtain accurate surface temperature of the billet in heating furnace has important practical significance. In recent years, as computer technology and photoelectric detection technology developed, colorimetric temperature measurement has been widely used in various fields. In this article, we used colorimetric temperature measurement into billet heating furnace, measured the surface temperature of the billet directly, and did the finite element analysis for the conduction of heat from the surface of the billet to the internal. Use the billet’s surface temperature inside the furnace measured by colorimetric temperature measurement system as a boundary condition of heat conduction, and establish a model to derive the internal temperature of the billet.In this paper, we first discussed the basic theory of thermal radiation, and the Planck’s blackbody radiation law to illustrate the basic principles of the colorimetric temperature measurement and introduced heat conduction relevant theoretical knowledge including the equation of heat conduction control, as well as initial and boundary conditions, and then, introduced the colorimetric temperature measurement system and temperature measuring processes, introduced the double optical path of the colorimetric temperature measurement system and some major hardware, such as: optical systems, photoelectric conversion device, image acquisition and analysis processing module; demonstrated a best dual-wavelength portfolio selection method when using the colorimetric temperature measurement; introduced three filtering methods to reduce the noise interference:the mean filter, median filter and multi-map average; did the finite element analysis for the conduction of heat from the surface of the billet to the internal. Use the billet’s surface temperature inside the furnace measured by colorimetric temperature measurement system as a boundary condition of billet heat conduction, and establish a mathematical model to derive the internal temperature of the billet, come to an accurate and reasonable result.