LAUSR

ABSTRACT In this study, we have investigated the degradation characteristics of surface radiation heat transfer properties of stainless steel 304. The emissivity (ε) and absorptivity (α) of stainless steel has been measured for a surface unexposed to sunlight and that exposed to sunlight for various time intervals (240, 480, 720, and 960 h). The temperature dependence of these properties is also measured for the temperature range of 30–300°C at 10 equal intervals. It is observed that the emissivity of the material increased when it is exposed to sunlight and the temperature dependence is very strong beyond 180°C. The absorptivity of the material increases first and then starts to decrease with exposure time. The combined effect of decrease in absorptivity and increase in emissivity leads to reduction in aS/E ratio, which results in a higher rate of radiation loss for exposed surfaces when compared to that for the unexposed surfaces.