Research On Spectral Emissivity Characteristic Of Several Commonly Used Steels

Steel is one of the most basic metal materials,which is widely used in many fields.Accurate measurement of temperature is critical in the production and processing of steel.The accurate temperature measurement will not only affect the quality and characteristics of steel,but also related to the level of energy consumption.The traditional contact method of temperature measurement can not be effective in most cases.Currently,radiation temperature measurement technology has been widely used in metal smelting and processing,and the problem of radiation temperature measurement technology is the uncertainty of spectral emissivity.Due to the factors such as temperature,oxidation,the emissivity of material is often a complex variable,which has become a problem restricting the development of radiation thermometry technology in the industrial processes.There are many types of steel,and the spectral emissivity characteristics are not the same.In this article,the spectral emissivity of five kinds of steel under different conditions was measured by using a set of spectral emissivity measurement system based on Fourier infrared spectrometer and a set of reflection emissivity measurement system.The effects of surface roughness,alloy composition and oxidation process on the steel emissivity were studied.The characteristics and the current problems of steel emissivity are introduced,and the present research status at home and abroad is summarized and analyzed systematically in the first chapter of this paper.The three research contents of this paper are also described.In the second chapter,the fundamental theory of the material spectral emissivity is described in detail.The spectral emissivity measurement system based on the Fourier transform infrared spectroscopy is introduced.The main components and measurement method are described,and the background radiation and response coefficients of the measuring device are tested.In the third chapter,the effects of surface roughness on the steel emissivity before and after oxidation are investigated by comparing the emissivity of six kinds of surface-treated E235 B steel at 2-15?m.The result shows that the effect of surface roughness on the spectral emissivity in different wavelength ranges and temperatures is different.It is also verified that the optical roughness can indeed be used as a parameter to evaluate the effect of surface morphology on the spectral emissivity.However,the surface morphology cannot be described with a single parameter absolutely.It is also observed that the spectral emissivity of the steel samples after oxidation is significantly increased,and the emissivity curve is oscillating.In the fourth chapter,the influence of alloy composition on the steel emissivity before and after oxidation is investigated by measuring the emissivity of the low carbon steel(310),the medium carbon steel(45 #)and the high carbon steel(T10)at 2-15?m.The result shows that the alloy composition will effect the steel emissivity,and this effect due to the difference in is different before and after oxidation.Nevertheless,the emissivity differences caused by alloy composition not more than 0.05,and it is observed that the color of the oxide film is different after the oxidation process.In the fifth chapter,the emissivity of steel Q235 A is measured from 300 K to 923 K by using a reflection emissivity measurement device in real time.The effect of oxidation process on the steel emissivity is investigated.The result shows that oxidation process has a significant effect on the steel emissivity.The emissivity of steel Q235 A is not always increasing in the heating process.There will be some fluctuations in the emissivity curve.Finally,the thickness of the steel oxide layer is estimated by using the interference theory.The purpose of this article is summarizing the general law of the steel spectral emissivity by studying the various factors affecting the steel emissivity,and enriching the emissivity data of steel.Hopefully these data can promote the further research on the steel emissivity and their characteristics under different conditions.