Turbo-stop: Turbulence inhibitor or commonly known as turbo-stop is a specially designed alumina base low cement castables. It is a pre-cast pre-fired(PCPF) refractory product which is placed over the impact plates or impact pads of the ladle stream. It homogeneously distributes the volume of steel flow to all the strands. It also minimizes the erosion of the permanent lining in the pouring area by reducing the molten steel turbulence and also directs the flow of steel upwards to enable capturing of non-metallic inclusions in the tundish surface layer.
Impact pad: An impact pad is placed underneath the turbo stop. The purpose is to resist the strong mechanical aggression by the steel stream when the turbo stop becomes worn out or damaged. The impact pad ensures proper sitting of the turbo-stop and equally distributes the impact pressure of the impinging metal stream on to the turbulence inhibitor. It is an alumina-based low cement castable PCPF refractory product.
Spray Mass: In most cases, a basic spray mix is used for the working lining, with a composition that is chemically inert towards liquid steel. (Normally, 68% – 70%MgO which ensures longer casting duration).The working lining facilitates easy removal after rendering its service and is to be newly applied after every cast sequence. The thickness of the spray-gunned layer is about 40 mm in the wall area and about 50 mm on the bottom. After spraying, the tundish should be dried as per the drying schedule.
SEN: Submerged entry nozzles (SEN) is a refractory material that feeds the molten steel into the copper mold from the tundish. The body of the SEN is usually made up of alumina carbon of 20-25% C (94% graphite) and 70-75 % alumina(tabular fused alumina with mullite additions) while the top part of the body consists of lower carbon and no zirconia while the slag line may contain 0-5% zirconia with 25%C. Antioxidants like Al, Si may be added to protect the carbon. Interior liner of low silica or carbon or high free lime may be added to prevent buildups. The body of the SEN is covered by the ceramic paper to prevent heat loss from the nozzle during the time of preheating and service. SEN helps to regulate the flow pattern of the molten steel in the mold. It also prevents the contamination of metal with air and minimizes the loss of heat to the outer environment.
MBS:- Monoblock stopper is the special type of flow control refractory product which controls the flow of the molten steel into the tundish. It is usually made up of Alumina graphite mix [20-25% C(94%graphite) and 70-75% alumina with mullite additions]. The tip is an area of high wear and will normally have zirconia or alumina for a standard tip but magnesia in case of high amount of calcium grades. The slag line composition is chosen to match the tundish slag composition and is basically alumina or zirconia or magnesia with carbon mix. Antioxidants like Al, Si may be added to protect the carbon. Sometimes permeability is ensured to promote optimum argon gas flow. Positive pressure is maintained inside the stopper to avoid air suction. The material possesses good resistance to erosion by steel and slag. The primary function of MBS is to regulate metal flow from tundish to the mold.
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