Application of High‑Temperature Visual Thermometers in the Iron and Steel Industry
Temperature measurement is required in many processing procedures of the iron and steel industry. Thermocouples are widely used in most scenarios. However, contact measurement is not feasible in certain applications, due to continuously moving solid steel materials or harsh operating environments that prevent the use of contact probes. For these special working conditions, high-temperature camera thermometers for imaging temperature measurement deliver remarkable advantages.
Long-distance imaging and non-contact temperature measurement can be well integrated and applied in multiple steelmaking processes, such as heating furnaces and rolling mills. By uniquely combining video imaging with infrared temperature measurement in a flexible manner, high-temperature camera thermometers serve as an excellent tool to optimize monitoring and temperature detection performance. This integration opens up new solutions for steel plants that have not previously adopted monitoring cameras, and notably simplifies furnace maintenance. This article focuses on the potential application scenarios of high-temperature camera thermometers in steel mills, and introduces temperature measurement for solid and liquid steel.
Temperature Measurement in the Iron and Steel Industry
In general, accurate infrared temperature measurement on steel is challenging due to its low emissivity. Emissivity is an inherent material property that indicates the amount of infrared radiation emitted by a surface, compared with a perfect blackbody (emissivity = 1, an ideal full radiator). A higher emissivity value means greater radiant energy received by the detector. Fundamentally, the higher the emissivity, the easier it is to measure the surface temperature of an object.
For steel products, emissivity varies with temperature, surface conditions and chemical composition. Surface condition is a key variable that greatly affects emissivity. For instance, non-oxidized stainless steel in processing conditions has an emissivity of approximately 0.4. Heavily oxidized, dark surfaces have an increased emissivity of 0.8, while polished, bright surfaces drop to around 0.2.
High-temperature camera thermometers support flexible, independent emissivity adjustment for any cursor-selected area on the display screen. Therefore, reliable and accurate temperature readings can be obtained as long as the parameters and characteristics of the processed steel materials are clearly defined.
