Modification of oxide inclusions in calcium-treated Al-killed high sulphur steels

A study has been carried out to understand the modification of alumina inclusions in Al-killed high sulphur steel with calcium treatment. For calcium treatment to be effective, a general practice is to desulphurise the steel to prevent the formation of solid CaS inclusions that are harmful to steel quality and final properties. To avoid this additional desulphurising step, the authors developed a new approach of calcium treatment of steel at an industrial scale. This approach involves treating the liquid steel with calcium treatment at low aluminium levels which enables formation of liquid calcium aluminate inclusions (C12A7) in the melt and then adding remaining amount of required aluminium. Based on this principle, Al-S diagram has been developed and calcium treatment has been modified accordingly. The inclusion transformation and morphology were studied using scanning electron microscope /energy dispersive spectroscopy analysis and. activity of CaS was calculated.Accepted Author Manuscript(OLD) MSE-

Grain Boundary Serration in Nickel-Based Superalloy Inconel 600: Generation and Effects on Mechanical Behavior

Grain boundary serration in the superalloy Inconel 600 was studied. Two microstructural variants, one with nonserrated and the other with serrated grain boundaries were generated by altering the heat-treatment conditions, while keeping other aspects of the microstructure unchanged. The effect on the creep response between 700 °C and 900 °C was measured, and the different failure modes and accumulated damage were quantified using high-angular resolution electron backscatter diffraction analysis in the scanning electron microscope and also by X-ray computed tomography. It is found that serration plays a more crucial role in the high-temperature/low-stress regime when an intergranular cracking mechanism involving cavitation is operative; here it plays a role in improving both creep life and creep ductility. Any effect of serration is less prevalent at low temperatures where transgranular failure is dominant