Abstract
Microalloying can significantly enhance the strength levels of low- and higher-carbon steels through grain refinement and precipitation. The role of niobium and titanium microalloying additions on the ferrite/pearlite banded microstructure and properties of low carbon hot rolled steel has been studied. A banded structure and microsegregation were observed which primarily contributed towards the anisotropic behaviour of the steel. The changes observed in the fracture morphology along and across the rolling direction of the impact specimens were consistent with banded microstructure. It was noted that microstructural and microchemical banding occurs primarily as a consequence of the rejection of substitutional alloying elements during solidification. However finer prior austenite grains may also be associated with the well defined banded microstructure observed in the steel containing microalloying additions. The grain refinement and precipitation strengthening in addition to change in the morphology of the non-metallic inclusions can be attributed to the microalloying additions in the steel.
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