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Selection requirements of refractories for refining ladle slag line

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  In the past, magnesia-chrome bricks and high alumina bricks were mainly used for refining ladles as lining refractories for slag line parts and low-corrosion areas respectively. Considering the requirements of environmental protection, except for the vacuum deoxidized ladle, all chromium-free have been realized, and ladle magnesia carbon brick or magnesia-carbon-calcium brick is used as the refractory material for the lining of the slag line, and the molten steel is vacuum refined (Including refined low-carbon and super-carbon steel) The lining of the ladle slag line is made of low-carbon magnesia-carbon bricks. The choice of ladle magnesia carbon bricks or magnesia-carbon-calcium bricks for the refining ladle slag line mainly depends on the refined steel type, slag characteristics and operating conditions. The advantages of magnesia-carbon-calcium brick: The research results show that: in the CaO-SiO2 system slag (low alkalinity slag), the magnesia-c...
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What causes tundish nozzle clogging

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  Tundish nozzle clogging introduction: Clogging of the tundish nozzle is a major castability problem in continuous casting of steel for several reasons. Firstly, clogging increases the frequency of operation disruptions to change nozzles or tundishes or even to stop casting. These extra transitions increase operating cost, decrease productivity, and lower quality. Secondly, clogging can lead directly to a variety of quality problems. Clogs change the nozzle flow pattern and jet characteristics exiting the ports, which can disrupt flow in the mold, leading to surface defects in the steel product and even breakouts. Dislodged clogs also disturb the flow and either become trapped in the steel or change the flux composition, leading to defects in either case. Quality problems also arise from the mold level transients which occur as the flow control device compensates for the clogging. Clogging is a complex problem which has received a great deal of past study....
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Factors affecting the quality of tundish repair

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  1. Loose Wall The looseness of the tundish wall is mainly reflected in the contact position between the tundish wall and the bottom of the tundish. The looseness of the wall is manifested in two forms: one is that it extends longitudinally from the position of the wall to form an irregular surface; The other is that the elongated powder falls down to form a "slit shape". There are two reasons for the looseness: one is that the binder volatilizes, resulting in a decrease in the overall bonding strength, especially the outermost one; the other is that the fine powder containing resin does not wrap the particles, which eventually causes slag to fall off easily. The low-temperature baking strength and medium-temperature strength of the dry-type material can be better improved by mixing boron glass powder and phenolic resin in the magnesium dry-type material . Based on the site conditions, it was found that the reasons for the low quality of the tundish re...
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Advantages of exchangeable system via sizing nozzle

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  1. Applying the technology of exchangeable the sizing nozzle can avoid excessive casting speed and steel leakage accidents caused by excessive nozzle erosion. 2. Increase the number of single-ladle continuous casting furnaces, reduce excess steel in tundishes, improve slab yield and slab quality, and achieve the purpose of reducing costs and increasing benefits. 3. It can realize quick stop of pouring, re-starting of pouring and replacement of sizing nozzles with different apertures during the casting process, so as to adapt to the best matching of molten steel temperature, fluidity and casting speed in the later stage of casting, as well as the matching with the supply of molten steel in front of the furnace, and promote production organizational balance and stability. 4. Improve the service life of the tundish, reduce the consumption of tundish lining refractory materials, baking energy, and manpower for laying the tundish. However, the exchangeable syst...
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Tundish masonry quality improvement plan

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  1. Optimizing the dry material composition and standardizing the fabric The continuous casting tundish plays an irreplaceable role, and the working layer of the tundish is the basis for protecting the normal and safe operation of the tundish. At present, the material of the tundish is magnesium dry material , and the uniformity of the cloth needs to be ensured, and the uniformity of the cloth of the working layer is the basis for the corrosion resistance of the refractory material. Therefore, starting from the operation, the following optimization schemes are proposed: (1) According to the research of Chen Changping, the strength of the working layer after demoulding is increased to meet the construction requirements, and the strength after high-temperature firing is reduced to meet the needs of disintegration of residual lining after offline. The amount of resin added in the dry material (w) is controlled at 1% to 3%; (2) The three sides of the ...
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Measures of magnesium dry material in continuous casting workshop

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  1. The situation before switching Due to the history and production status and other reasons, the tundish working layer used in the production of Tanggang No. 2 Steel mill is mostly silicon plate, only one continuous casting machine uses part of magnesium coating, the average life of the tundish is only 6 ~ 7h, the operation rate of the continuous casting machine is only about 70%. Because the life of tundish is too low, and the amount of head and tail billet and tundish is too large, the consumption of steel material is too high, the average consumption of steel material is about 12kg. Moreover, due to the poor sintering effect and sintering strength of the silicon plate, the pollution of the silicon plate to the molten steel is too large, which can not meet the requirements of casting purity. 2. Use specific measures and effects (1) Improve and optimize the materials of the intermediate working layer Tundish working layer is the key point of tundis...
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Brief introduction of Electric Arc Furnace lining repair

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  Furnace repair is mainly the vulnerable parts in the EAF gunning furnace , which mainly includes: (1) Furnace wall slag line position The part of the lining in the steelmaking furnace that is close to the slag layer is called the slag line part of the lining because it is often in contact with the steelmaking slag. The slag contains calcium oxide (CaO), silicon dioxide (SiO2), ferrous oxide (FeO), calcium fluoride (CaF2), manganese oxide (MnO), aluminum oxide (Al2O3), etc. At high temperature, the acidic oxides in the slag react chemically with the basic furnace lining to form low-melting point compounds, which reduce the refractoriness of the furnace lining. Coupled with the physical scouring effect of the slag flow, the slag line of the furnace lining is severely damaged. The nearby slag line is more seriously damaged due to the high temperature radiation of the arc light. (2) Furnace wall hot spots The arc temperature reaches about 4000°C, and the area ...
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