matters needing attention in the production of castings from scrap steel
Synthetic cast iron means that the charge does not use pig iron, and is mainly composed of scrap steel, reclaimed charge, and iron filings. The recarburizer is added in the smelting to obtain the required carbon from the molten iron, and it is obtained by rational use of the temperature characteristics of the intermediate frequency induction furnace and the effect of electromagnetic stirring. High-quality molten iron. A process method to obtain high-quality cast iron products by strengthening inoculation during pouring.
The key points of making synthetic cast iron are:
1.High-quality raw materials. Including scrap steel, recarburizers, inoculants, spheroidizing agents, etc. The scrap steel is preferably carbon scrap with low carbon, low sulfur, low phosphorus and no impurity elements. The current carbon steels are all aluminum-killed steels, and the remaining aluminum in the cast iron may cause defects such as casting pores, which must be paid attention to. The recarburizer is preferably calcined petroleum coke after high temperature graphitization treatment. Nowadays, the manufacturers of recarburizers are everywhere, and the quality is uneven, which also requires attention. According to the form of carbon, recarburizers can be divided into crystalline graphite recarburizers and amorphous graphite recarburizers. The crystalline graphite recarburizer undergoes high-temperature graphitization treatment, and its C atoms change from the original disorderly arrangement to the sheet-like orderly arrangement, which can become a good graphite nucleation core. Severely rusty and humid charge will bring in a large amount of oxygen and hydrogen and consume the carbon in the recarburizer, so it should be avoided as much as possible. Synthetic cast iron eliminates the genetic adverse effects of raw materials such as pig iron. The smelting process is stable, the composition is uniform, and the structure is stable. Synthetic cast iron can consume raw materials such as recycle materials and chips, which can effectively reduce production costs.
2.The choice of inoculants. The characteristics of the hot metal of the electric furnace are quite different from that of the cupola hot metal. Its supercooling degree is high and the crystal nucleus is less, so it must be inoculated. This is crucial. According to the current inoculation theory, if you do a good job of inoculation with the flow, also known as immediate inoculation, you should choose a long-acting inoculant containing barium, calcium, strontium and other trace elements. There are thousands of inoculants on the market now, and you need to choose the products and inoculation process that suit your own use.
3.Silicon carbide pretreatment. Silicon carbide pretreatment is also a hot process in recent years. However, due to the uneven quality of silicon carbide in the domestic market, the inherent concept has not been changed in time, the operation process and details have not been in place, resulting in various problems in the use of silicon carbide. Affected its promotion. You must carefully explore the brand craftsmanship suitable for your own use.
4.High temperature and overheating and stand still treatment. The advantage of high temperature overheating is that it improves the uniformity, facilitates the floating of slag gas, and greatly improves the quality of molten iron.
5.Reasonable feeding sequence and power distribution system. The temperature controllability and electromagnetic stirring effect of the intermediate frequency induction furnace provide good conditions for the production of synthetic cast iron. A reasonable power distribution system and feeding sequence can reduce the energy consumption per ton to the greatest extent.Is there any confused of castings, haha we Anyang Huatuo Metallurgy would like to share more experience with you.