inoculation process of gray cast iron
In recent years, the inoculation process of gray cast iron has developed rapidly, and there are many effective inoculation methods.For the production of gray cast iron, it is very important to choose a suitable inoculation treatment method, which is often a key factor in determining product quality.Each inoculation treatment method has its advantages, but also has certain limitations. So far there is no treatment method that can adapt to various production conditions. All foundry enterprises should select the method that best suits the characteristics of the enterprise through experiments according to their own specific conditions.
The widely used inoculation treatment methods mainly include:ladle inoculation, post inoculation, there are also exit the pretreatment before inoculation methods, here main focus on the ladle and post (in-stream) inoculation.
1.Ladle inoculation: It is an inoculation treatment used when molten iron flows from the melting furnace or holding furnace to the ladle.This processing method is simple and convenient, it is currently the most widely used process,It is best to start the inoculation treatment after the iron is tapped and the amount of molten iron in the ladle is about 1/4 of the amount of iron tapped, and the granular inoculant is evenly and dispersedly scattered to the liquid stream through a quantitative funnel, to the amount of molten iron in the ladle, the treatment ends at about 4/5 of the iron output.This ladle inoculation process of gray cast iron can make use of the stirring effect of the liquid stream to completely dissolve the inoculant in the high-temperature molten iron and improve its utilization rate. The particle size of the inoculant varies slightly depending on the amount of molten iron processed: when the amount of molten iron is less than 500kg, the particle size should be 2-5mm;when is 500kg, the particle size should be 5-8mm. The addition amount is generally 0.2~-0.4% of the amount of molten iron to be processed, which can be adjusted according to the type of inoculant and the wall thickness of the casting and determined by experiment. When iron is used for inoculation treatment with 75 ferrosilicon, the inoculation effect will quickly decline with the passage of time, 5-7 minutes after incubation, the decline of the effect can be more than 50%, after about 15 minutes, the inoculation effect will be mostly to all disappeared. In order to ensure the quality of castings, the pouring is usually completed within 10 minutes after the incubation, and it is best to incubate again when the molten iron is poured into the mold from the ladle.
2.Post(in-stream) Inoculation: it is the inoculation process of gray cast iron when the molten iron is poured into the mold from the ladle. The fine-grain inoculant can be added to the liquid stream.There is no problem of inoculation decay during inoculation and pouring of fine-grain inoculants. Generally, the used inoculant is 75 ferrosilicon, and inoculants containing other alloy elements can also be used when there are special requirements. In order to make the inoculant quickly dissolve in the molten iron and be evenly distributed in the molten iron, fine particles should be used generally 0.2-0.8mm. The added amount is roughly 0.15% to 0.2% of the molten iron.
There are several different inoculants for gray cast iron, such as ferrosilicon, barium silicon, barium ferrosilicon, silicon carbide etc, Anyang Huatuo Metallurgy Co., Ltd has in various inoculants for more than 10 years, also own rich experience for inoculation process of gray cast iron, so if any confused just contact us.