Effect of microstructure on slurry erosion behaviour of weld hardfacing alloys

Abstract

In the present work, the slurry erosion behaviour of weld hardfacing alloys was investigated by systematic variation of identified test parameters and the response data were generated from a suitably designed experimental plan. The identified groups of parameters were operational parameters; velocity, slurry concentration, and particle size of the erodent; and relative hardness of erodent particle and the microstructural parameter, carbide volume fraction (CVF). The slurry erosion experiments of hardfacing alloys with different Cr and C content were conducted using a pot-type slurry erosion tester with silica sand slurry of different concentration over a range of velocities. The slurry erosion volume loss of hardfacing alloys exhibited different trends under different test conditions with identified parameters. The slurry erosion volume loss decreased with increasing CVF and H_e/H_t, (ratio of hardness of erodent to hardness of target) except under severe erosion test conditions where the reverse trend was observed. An empirical correlation was proposed, in which the slurry erosion rate was expressed as a product of operational parameters, microstructural parameter, and relative hardness of erodent particles. Scanning electron microscopy observations were focused on gaining additional information associated with the mechanism of material removal under different experimental conditions.