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One of the tundish major functions,is the reduction of impurities,i.e.non-metallic inclusions.Various arrangements,which promote floating of non-metallic inclusions into slag,are provided by continuous casting techniques.The most effective method is the injection of argon into the liquid steel in the tundish through special purging plugs.Hence.the positive results are achieved with the reasonable selection of purging plugs location and argon flow rate.In the present paper,the results of physical modelling of non-metallic inclusions flotation process,are considered at gas purging into the tundish liquid bath.It is shown that these results depend upon the design of purging plugs,liquid flow direction,flow-rate of injected gas,etc.In industrial environment,it was found that at argon purging into the steel ladle,the amount of large single inclusions ( 1.5 points and over),is 10% - 25% lower than in reference slabs ( without purging).The best results were attained at gas flow-rate of 10 - 12 1/min per a purging plug.At higher argon flow-rates ( e.g.,15 - 16 1/min),the intense turbulence of steel and slag in the gate area of argon bubbles was observed,thus causing additional pollution in the tundish.The most beneficial effect can be achieved by the employment of porous purging plugs that provide venting in the bubbling mode with bubbles diameter under 3 mm.It is established that the most beneficial effect is attainable with the application of purging plugs placed at the tundish bottom around the tundish nozzle.