Synergism between effects of velocity, temperature, and alloy corrosion resistance in laboratory simulated fluidised bed environments

Abstract

In studies of the erosion of alloys at elevated temperature, the combined effects of velocity, temperature, and alloy corrosion resistance are not well understood. Wide variations in the effects of velocity have been observed for alloys of different corrosion resistance in various erosion–corrosion environments. There is also some evidence that temperature can affect this relationship. The object of the present work was to undertake a systematic study of the effects of erodent velocity for two alloys, mild steel and 310 stainless steel, at elevated temperatures (300 and 600°C). The velocity was controlled at values between 1·5 and 4·5 m S−l. Weight change data and analytical scanning electron microscopy were used to characterise the degradation in the various conditions. The results showed that the ranking order of the erosion–corrosion rates of the two different alloys varied as a function of velocity. The velocity at which the ranking of the two alloys reversed increased with increasing temperature. The reasons for such behaviour are discussed in terms of the dependence of the erosion–corrosion rate on the velocity in the various erosion–corrosion regimes.MST/3188