Effect of Manganese and Molybdenum on the Microstructure, the Shape of Secondary Precipitation, and the Wear Behavior of a High Chromium Cast Iron

In various industrial fields, where the material wear is a prevalent stress, the microstructure of wear-resistant materials plays a very important role. The operational behavior of these materials differs depending on whether the microstructure consists of an austenitic or martensitic matrix. Moreover, the type, shape, and morphology of the secondary carbides produced by the heat treatment have a significant effect on the wear resistance of the material. This work investigates the effect of manganese and molybdenum on the microstructure type, the secondary precipitation, the thermal behavior, the microhardness, and the wear resistance of high chromium cast iron balls, used for raw material grinding. Basic and alloyed cast iron samples were processed in an induction furnace and characterized by spectroscopic, optical, and SEM microscopy, XRD, and DSC techniques. The secondary precipitation grain surface was measured using the ImageJ software. Microhardness and wear tests were considered to check the sample abrasion and friction resistance. The obtained results show the effect of manganese and molybdenum on the microstructural and wear properties of the cast iron. Compared to the basic cast iron, the addition of 3% of manganese favorably affects the secondary precipitation by inducing dense precipitation of carbides with polygonal morphology. On the other hand, the effect of the addition of manganese and molybdenum was reduced by a factor of six, resulting in a lower proportion of secondary carbides but better wear properties. The recorded thermograms show that molybdenum shifts the eutectic transition peak to higher temperatures compared to the manganese effect.