SYNERGISM BETWEEN EFFECTS OF VELOCITY, TEMPERATURE, AND ALLOY CORROSION-RESISTANCE IN LABORATORY SIMULATED FLUIDIZED-BED ENVIRONMENTS

In studies of the erosion of alloys at elevated temperature, the combi ned effects of velocity, temperature, and alloy corrosion resistance a re not well understood. Wide variations in the effects of velocity hav e been observed for alloys of different corrosion resistance in variou s erosion-corrosion environments. There is also some evidence that tem perature can affect this relationship. The object of the present work was to undertake a systematic study, of the effects of erodent velocit y for two alloys, mild steel and 310 stainless steel, at elevated temp eratures (300 and 600 degrees C). The velocity was controlled at value s between 1.5 and 4.5 m s(-1). Weight change data and analytical scann ing electron microscopy were used to characterise the degradation in t he various conditions. The results showed that the ranking order of th e erosion-corrosion rates of the two different alloys varied as a func tion of velocity. The velocity at which the ranking of the two alloys reversed increased with increasing temperature. The reasons for such b ehaviour are discussed in terms of the dependence of the erosion-corro sion rate on the velocity in the various erosion-corrosion regimes. (C ) 1995 The Institute of Materials.