Study of SG iron and its tribological behaviour

Abstract

Erosive wear tests were performed on different alloys composition of SG iron using air jet erosion test rig. Erosion damage was measured by the removed material volume at impact angles 30¢ª, 45¢ª and 60¢ª. The effect of impact angle, standoff distance and pressure in wear features of specimens were discussed as mechanism of erosive wear by using the taguchi¡¯s analysis. The objective was to investigate which design parameter significantly affects the erosion wear. It was found that the pressure and impact angle is the most powerful factor influencing the erosion wear rate. The surface morphology shows erosion mechanism of the spheroidal graphite at the surface deforms gradually, lips are produced in the direction of the blast, and they extend, and finally drop off. This process of growth, extension, and dropping off is repeated, but life spans are different depending on the material. The basic mechanism of the erosion damage is at first the plastic transformation near the surface due to the impacts. In this study we deal with determination of crystallite-size distribution and microstrain measurement of SG iron by the means of x-ray diffraction line broadening method. XRD analysis shows that only ferrite phase is present mainly in all samples of SG iron. It was shown that nodular cast iron has excellent erosion resistance and it is expected to find wide applications as a wear-resistant material. Nodular cast iron (SG iron) shows the highest wear resistance probably due to its graphite morphology which controls crack propagation and thermal conductivity.