No abstract

No abstract

Synopsis:Contribution of tundish slag entrainment, reoxidation, and refractory errosion, to the amount of large nonmetallic inclusions occurring during teeming in continuously cast slabs has been determined with tundishes of varying design equipped with different type of nozzles. Reoxidation taking place during teeming from ladle to tundish, travelling in tundish, and teeming through tundish nozzle, has also been evaluated separately. The fraction of large inclusions occurring from the entrainment of tundish-or mould-slag has been examined by use of La2O3 or CeO2 as tracer. Most of large inclusions has been found to be of exogenic origin arising mainly from air reoxidation and tundish slag entrainment.On the basis of these observations, a combination of specifically designed tundish and tundish nozzle has been developed to virtually remove inclusion accumulation in the upper quarter thickness of continuously cast slabs for deep drawing-ironing strip steel and control-rolled high strength strip steels.

No abstract

The effect oj fluid flow in crater on the amount and distribution of large oxide inclusions in continuously cast slab has been investigated with two types oj bi/urcated submerged nozzles on a bow tytJe caster with radius oj 10 m. A bottle tytle nozzle, which gives shallower twzetration oj casting streall! and hence inclusion into crater, has resulted in a narrower and weaker accumulation oj inclusions in through-thickness direction of the inner radius side of slab. The accumulation disappears by decreasing the pelletratioll depth oj inclusion to be less than about 1. 5 m .