Steel Teeming Ladle and its Refractory Lining Nov08

Steel Teeming Ladle and its Refractory Lining...

Steel Teeming Ladle and its Refractory Lining Steel teeming ladle (STL) is needed in a steel plant to contain and transport liquid steel from the steel making furnace to the casting facility. These days STL is used in a significantly more complex manner than the older steel melting shops where ladles were used simply to transport liquid steel from a steel making furnace to the ingot moulds. Other functions carried out in the STL are temperature control, deoxidation, additions of carburizer and ferro-alloys and inclusion floatation. In the recent past, the demand for various grades of steel with stringent specifications has increased considerably. These steels are produced using secondary refining processes. The lining of the STL must withstand increasingly severe service conditions associated with the secondary refining processes. These severe conditions are longer holding time, higher liquid temperature and arc/chemical heating. Rinsing with inert gas and degassing of the liquid steel, alloying and use of synthetic slag also accelerate the wear of lining. Because of these activities the demand on the quality of STL refractories has increased very much. In present day steel melting shops STL functions as traveling components of skimming, rinsing, reheating, and degassing processes. The exposure time for a given heat in these shops has expanded from two to five times of the time earlier needed for ingot teeming. STL is also required to conserve heat by minimizing heat loss during transport and during the various process steps. In this regard, significant developments have been made to properly preheat ladles prior to the first heat, and to cycle ladles on subsequent heats in a manner to minimize heat losses. STL is designed to be heat resistant and strong. Also it is necessary to heat insulate the ladle. Proper heat insulation is...