A mold powder is defined as a powder or granular material added to the top of molten steel in the continuous casting mold, which partially melts forming a liquid layer next to the molten steel. This liquid, now known as a mold flux, protects the steel from reoxidation, absorbs the non-metallic inclusions, lubricates the steel shell as it passes through the mold, and controls the heat transfer from the solidifying steel shell to the mold. Particle size, shape, and bulk density will affect the flow ability of powder material.