Abstract:
Very common in steels with low carbon content, the presence of elements such as aluminum and calcium increase the amount of non-metallic inclusions immersed in the bath during refining. In Continuous Casting, liquid steel may be exposed to the atmosphere due to a failure in the sealing of the ladle slide gate, for example, resulting in re-oxidation of the metal bath, which may lead to obstruction of the ladle monobloc (ladle slide gate and ladle shroud), resulting in sequence cut or production deviation. Another operational emergency that affects internal quality is the non-instantaneous ladle opening. In order to avoid the loss of the heat, the ladle slide gate is unobstructed through a manual device coupled to an oxygen outlet, which, when activated, releases a flame that removes the solidified region at the valve outlet. However, this type of procedure generates a risk for the operator due to the possible projection of liquid steel at the time of unclogging, in addition to the exposure of the steel to the environment (open-jet) which may cause a downgrade in production due to re-oxidation. With the aim of bringing more safety to the operator and reducing the deviation of slabs cast with open jet, a device called SOS was implemented, that takes the operator out of the risk zone and brings more quality to the process in general. From the implementation of the device, a 32% reduction in slabs downgraded due to reopening event and non-instantaneous ladle opening was achieved.