Mathematical model to predict effects of fly ash hardness and angularity on erosion response of typical boiler grade steels

摘要

A theoretical model has been developed embodying the ductile erosion mechanisms involving cutting wear, plastic deformation and surface temperature on the erosion response of typical boiler grade steels. The parametric sensitivity of erosion response of these steel grades as a function of particle impact velocity, angle of impingement and steel surface operational temperature has been investigated, which also accounts for particle properties such as hardness (silica content) and shape (angularity). The investigation demonstrated that a minor rise in the fly ash hardness can considerably enhance the erosion rate of the steel surface, signifying that the hardness of fly ash can be a crucial parameter for characterising the ductile erosion potential of various boiler grade steels. The effect of fly ash angularity (shape) on the erosion behaviour is also studied. The erosion resistance of the surface is found to be dependent on the steel composition, specifically the amount of chromium content and tensile properties (yield strength) of the steel.