Investigation of Residual Stress and Elastic Parameters Affected Due to Variations in Manganese Content and Cast Section Size in Wear Resistant High Chromium Irons

The ferrous-based system especially high chromium alloyed irons are known for superior wear behavior in view of possessing hard carbides in a martensitic phase, but prone to failure upon load application. The improvement to withstand load is possible through the addition of manganese element to chromium as it serves as an austenite stabilizing agent. These alloys are subjected to different processing conditions, such as designing of alloy systems, heat treatment cycles, cooling rates etc., before considered for actual field applications such as grinding media, liners, impellers in thermal power plants. These components are subjected to various manufacturing processes resulting in onset of residual stress in the form of plastic strain. During the processes such as casting, machining, welding and heat treatment, one region of a part gets constrained by the adjacent region resulting in expansion or contraction, releasing elastic strains, thus introducing residual stress. These stresses have impact on the mechanical performance involving elastic parameters such as Young’s and Shear modulus as well as Poisson’s ratio. Therefore, it is very much required to enlarge the scientific database of chromium manganese irons on the parameters relating to residual stress and elastic constants as they are significantly less explored. In this study, chromium irons have been prepared in grey cast iron moulds by induction melting and subjected to hardness, residual stress, sonic tests and microstructure involving carbide morphology in the heat-treated conditions. The data gathered due to the change in cooling rate through the variation in cast section thickness from 12 to 40 through 24 mm in 5% and 10% Mn-added chromium irons, have resulted in better correlations among residual stress, elastic constant, hardness and metallurgical parameters.