关键词: 12Cr钢, 发射率, 红外测温仪, 水蒸气, 氧化

Abstract: The surface temperature of large rotating machinery is an indispensable parameter for the strength design and life assessment. The infrared radiation (IR) pyrometry is a type of non-contacting measurement technique which can be used to detect the surface temperature of rotating machinery directly. The oxidation film of steam turbine rotors, due to being operated in high parameters steam for long terms, is one of the most important factors for IR pyrometry. To study on the influence of oxidization on IR pyrometry, the 12%Cr steel samples were oxidized in supercritical water vapor (up to 24 MPa/400 ℃) in the presented device , then the emissivity of the oxidized samples were measured with a monochromatic pyrometer. The results show that growth rate of the emissivity measurements varying with temperature and their dispersion were decreased with the development of being oxidized gradually. It suggests that the monochromatic pyrometer can be used to detect the temperature variation of objects with setting fitted emissivity (such as 0.88). It is demonstrated that IR pyrometry could be applied to monitor the surface temperature of steam turbine rotors.

Key words: 12%Cr steel, Emissivity, Infrared radiation pyroemeter, Oxidization, Water vapor