Influence of Austenite Phase Transformation on Existing Microstructure of Low C-Mn Steel

S. H. Abro, A. Chandio, A. R. Jamali, S. A. Shah


Cold heading quality CHQ steel is widely used for making small components due to its excellent cold heading response. Austenite nucleation and growth morphology of a commercial CHQ steel has been studied by continuous heating experiments using lead-bath up-quenching at different heating temperatures. Modern optical microscope Olympus GX51, scanning electron microscopy techniques have been deployed to reveal and interpret the microstructure. It was found that at 740°C the microstructure shows lack of homogeneity, hence the cold-head-ability of CHQ steel is anisotropic. At high temperatures, in austenite domain, at 60sec, the resultant austenite is highly homogenous. Then the cold-head-ability properties of CHQ steel turned to be isotropic.


CHQ steel; up-quenching; phase transformation; microstructure; heating rate; austenite

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