The so-called recarburizer is to increase the content of carbon in the molten iron after it is added. Therefore, the fixed carbon content of the recarburizer must not be too low. Otherwise, to reach a certain carbon content, it is necessary to add a high carbon content. With more samples of recarburizer, this undoubtedly increases the amount of other unfavorable elements in the recarburizer, so that the ferrofluid can not obtain a better return.
Low levels of sulfur, nitrogen, and hydrogen are key to preventing the production of nitrogen holes in castings. This requires that the nitrogen content of the recharging agent be as low as possible. The other indicators of recarburizers, such as moisture, ash, and volatiles, the higher the amount of fixed breakage, so the high fixed carbon content of these harmful ingredients must not be high. For different smelting methods, furnace types, and sizes of smelting furnaces, it is also important to select an appropriate particle size of the carbon reductant, which can effectively increase the absorption rate and absorption rate of the recarburizer by the molten iron and avoid excessively small particles. Caused by oxidative damage to the breaker. The particle size is preferably: 100 kg furnace less than 10 mm, 500 kg furnace less than 15 mm, 1.5 tons furnace less than 20 mm, 20 tons furnace less than 30 mm. In the smelting of converters, when high-carbon steels are used, recarburizers containing little impurities are used.
The requirement for the recarburizer for top-blowing converter steelmaking is that the fixed carbon should be high, the content of ash, volatile matter and sulfur, phosphorus, nitrogen and other impurities should be low, and it should be dry, clean, and the grain size should be moderate. Its fixed carbon C> 97%, volatile matter <1.0%, S <0.5%, moisture <0.5%, particle size in l-5mm. The particle size is too fine to be easily burned, and it is too thick to float on the surface of the molten steel and is not easily absorbed by molten steel. The particle size of the induction furnace is 0.2-6mm, in which the steel and other ferrous metals have a particle size of 1.4-9.5mm, the high carbon steel requires low nitrogen, the particle size is 0.5-5mm, etc. The concrete need to be based on the specific furnace type smelting workpiece The details of the types and so on are specifically judged and selected.