In the process of smelting steel, due to improper ingredients or charging and excessive decarburization, sometimes the content of steel or iron does not meet the expected requirements. At this time, it is necessary to increase carbon in steel or molten iron, and add petroleum coke to increase carbon. Agent. Tar recarburizer is a substance usually used to increase carbon. The recarburizer is added to the metal smelting furnace to increase carbon through the dissolution and diffusion of carbon in the molten iron. The absorption rate depends on the dissolution and diffusion rate of the recarburizer and oxidation loss Speed promotes the increase of the carbon content in the molten iron, the reduction of the oxygen content in the molten iron, and more importantly, the improvement of the mechanical properties of the smelted metal or castings. That is, castings can be smelted from the worst scrap steel by using recarburizers.
Quality of tar recarburizer
Compared with the traditional process of smelting with recarburizer, there are many coarse hypereutectic graphite in pig iron. This coarse graphite has hereditary properties, the melting temperature is low, and the coarse graphite is not easy to be eliminated. The coarse graphite inherits from the liquid to the solid cast iron structure. In the process, on the one hand, it reduces the strength that the cast iron can achieve and reduces the performance of the material. On the other hand, it weakens the expansion effect of graphitization precipitation that should have occurred during the solidification process, and increases the shrinkage tendency during the solidification of molten iron. During cupola smelting, minimize the amount of pig iron charge, use a recarburizer to ensure high carbon equivalent, and relatively increase the amount of scrap. In this way, under the conditions of high-temperature smelting, carbon with good activity and more significant graphitization can be obtained by carburizing. It reflects the better shape of graphite on castings, which is beneficial to improve mechanical properties, reduce shrinkage tendency, and improve processing performance. During electric furnace smelting, high-quality molten iron can be obtained by carburizing with low pig iron consumption or even zero consumption. In terms of material properties, the large proportion of pig iron used in the past has a half-grade lower mechanical properties than high scrap steel with the same composition. Therefore, the new smelting process with recarburizer is superior to the traditional large proportion of pig iron in terms of cost and finished product performance.