Effect of Si on Microstructural and Magnetic Behaviour of Heat-Treated High Carbon Steel

SiliconSilicon (Si) is a versatile alloying element that can enhance the performance of high carbon steelHigh carbon steel by contributing to deoxidation, grain refinement, hardenability, strength, and toughness. The study investigates the influence of Si (0.8–3.6%) on the microstructural and magnetic properties of high carbon steelHigh carbon steel. The arrangement and density of magnetic moments, which are affected by the microstructure determines the saturation magnetisationSaturation magnetisation of the material. Industrial-grade high carbon steel samples with varying silica were microstructurally tailored to obtain multi-phase steel microstructures. The optical and SEMScattering electron microscopy (SEM) analyses revealed a combination of cementite and plate martensiteMartensite, wherein the martensitic structuresStructure became finer with higher Si content. The evolution of martensitic microstructures along with mild oxidation of Si inclusions in the grain boundaries of the surface were observed using Confocal microscopy. An increase in the cementite with an accompanied decrease in the martensitic fraction was determined by the quantitative analysis of the X-ray diffractograms. The saturation magnetisationSaturation magnetisation (MS) of the samples witnessed a gradual decrease with increase in the Si content. SiliconSilicon’s role in high carbon steelHigh carbon steel is quite notable, therefore, the nature of heat treatmentHeat treatment and level of Si addition can be adjusted to limit the formation of cementite and increase the ferritic martensiteMartensite or austenite in the microstructure.