MICROSTRUCTURE & MECHANICAL PROPERTIES OF FERRITIC LOW DENSITY STEEL

Abstract

Weight reduction of automotive steels is required to lessen the fuel consumption, and therefore minimises greenhouse gas ejection. It is found that addition of Aluminium to steel is a excellent option to make steel lighter because of its compatibility with steel. Although Al addition in steel does retain its crystal structure Aluminium addition in steels provides greater mechanical strength without significant loss of ductility. In present work, different compositions of Fe-Al systems have been studied. We found density reduction up to 10% after addition of Al (11 wt %) along with this to get some better properties like hardness and strength we quenched our samples from various temperature but here it is found that there is no martensitic transformation takes place although quenched it from austenitic phase and with above critical cooling rate instead of martensite there is k-carbide formation with variation in size and distribution of and that is responsible for various changes in properties. The Maximum strength of adequate Fe-Al alloys is greater than traditional steels such as ultra low or low carbon steels. In this study we are trying to find the reason behind the formation of k-carbide instead of martensite. In this study after getting carbide in matrix of ferrite we are focussing on effect of Microstructure on erosion resistant property of materials. The effect of carbides on erosion behaviour of material is quite complex in nature. There are contradicting outcome have been observed in the literature regarding the impact of carbides on erosion behaviour. Carbides possess great significance specially as hurdle for the penetration of erosive particles into the material surface whereas they are also, vulnerable to rupture and hence matrix decohesion which adversely reduce the overall erosion strength of material. Reduction of carbon in the austenite matrix in coarse carbide which adversely reduce the strain hardening strengthening results in decline in erosion strength of the predominant material. In this study it is observed that after quenching low density steel when there is change in microstructure and carbide size and its distribution and erosion resistance is best in which carbide size are small and uniformly distributed throughout matrix.