Effects of Microstructure and Morphology on Slurry Erosion Performance of Low-Carbon Bainitic Steels

An improved resistance of a low-carbon bainitic steel to slurry erosion was achieved by utilizing a heat treatment to alter the distribution map of M/A constituent,which refered to austenite and its transformation products. In light of elastic and plastic theorems such an improvement was attributed to that one particular M/A distribution had the capability to optimize the stress concentration intensity and therefore the erosion performance. The steel studied here was transformed into four different metallurgical structures: bainite with thin-film M/A,bainite with granular M/A,pearlite and martensite. It is found that pearlite and martensite had the worst erosion resistance due to the mismatch of strength and toughness,and that bainite with granular M/A also had a relatively low erosion resistance since the cracks on the erosion surface grew into the inner part of the steel resulting from the point of stress concentration itself extending inwards. Bainite with thin-film M/A,however,had the best erosion resistance because the particular stress concentration prevented cracks from propagating inwards.