Effect of retained austenite on abrasion resistance of high-Cr white cast irons

Superior abrasive wear resistance, combined with relatively low production costs, makes high-Cr white cast irons particularly attractive for applications in the grinding, milling and pumping apparatus used to process hard materials, such as ore, coal, gravel and cement. in this study, 5x5x18 cm iran blocks, with a composition of 3.1 C and 24.5 Cr (wt%), were cast into sand molds. The blocks were heat-treated in five different schedules to vary the retained austenite content. A pin abrasion test and a single scratch test,were used to determine the abrasion characteristics of the test specimens. Hardnesses and impact fracture energies of the as-cast and heat-treated samples were also measured. Optical and scanning electron microscopy (SEM) and an x-my diffraction techniques were used to characterize the microstructures and the wear surfaces. The results indicate that better abrasive wear resistance is obtained when the matrix contains a mixture of austenite and martensite. A fully martensitic matrix, on the other hand wears the fastest, with extensive plastic deformation and fracturing of the wear surface.