Selection of Mould Fluxes for Production of High Quality Steel Ingots

Introduction Ingot products account for 8.3% of the total crude steel produced in the world. It is produced either by top pouring or bottom pouring of the liquid in the moulds. The increasing demand for quality steels led to the evolution of bottom pouring technology for casting of steel ingots. This process constitutes of a set up involving pouring sprue and runner system to deliver liquid steel into the bottom of one or more cast iron moulds as shown in Fig.1. The application of this bottom pouring technology for production of quality ingots has been mainly due to the reduced turbulence of steel in the mould caused by controlled flow of liquid steel in the mould to result in quiet meniscus leading to superior as cast ingot surface, minimal splashing of liquid metal droplets from ladle stream providing freedom from scab type defects, application of steel meniscus during teeming for completely covering the slower teeming rates that reduce turbulence, longitudinal cracks meniscus and maintaining a powder layer through out the casting formation & minimize laps and ripple marks and finally, process that helped in drastically reducing or even eliminating improved mould life. defects such as laps, ripple marks, entrapment of oxides, surface The application of fluxes for bottom pouring has been a common cracks and pinhole porosity of the ingots. Ever increasing demand practice for a long time. These are added to the top of the rising for quality steel products accelerated the continuous development