Classification of inoculants (1) Ferrosilicon inoculant. Ferrosilicon inoculants are divided into three types: 45FeSi, 75FeSi, and 85FeSi. The treatment effect of 45FeSi inoculant is poor, and the cost of 85FeSi is higher, and 75FeSi is commonly used. Ca and Al in 75FeSi have a great influence on the inoculation effect, among which Ca has a great influence, and when it is greater than 0.5%, it has a strong ink-forming ability. Generally, 75FeSi chooses the following chemical composition ranges, Si: 74% to 78%; Ca: 0.5% to 1.0%; Al: 0.8% to 1.5%. (2) Silicon barium inoculant. Silicon barium inoculants are mainly used in the production of gray cast iron and ductile iron. It can significantly increase the number of graphite nodules when used in ductile iron, and can reduce the tendency of white mouth when used in gray cast iron. Refine grains and improve graphite morphology. In addition to high mechanical properties, this kind of inoculant also has strong anti-recession ability. Generally, the inoculant contains Ba between 2% and 3%.

The effect of temperature on inoculation Proper superheating of molten iron in the furnace can improve the inoculation effect and improve the mechanical properties of cast iron. However, if the heating temperature is too high, some SiO2 that can become the nucleation matrix is reduced sharply by carbon reduction, and the inoculation effect is reduced. Experiments show that the tensile strength of low-carbon gray cast iron after inoculation is more affected by the superheating temperature of molten iron than that of cast iron with higher carbon content. The temperature of inoculation treatment should ensure that the inoculant can be fully melted. Excessive molten iron temperature will reduce the activity of carbon in molten iron, reduce the graphite nucleation rate, and accelerate the melting of the inoculant, leading to the early occurrence of the inoculant recession process. Various inoculants have their own suitable processing temperatures: 1380-1420 ℃ for 75 ferrosilicon and silicon-based composite inoculants, 1400-1430 ℃ for silicon-calcium inoculants, and 1430-1460 ℃ for carbon-silicon inoculants. No matter which inoculant is used, the inoculation temperature of ductile iron should generally not be lower than 1350℃.

The relationship between inoculants and infertility decline Inoculants and inoculants are closely related. The inoculation time of silicon is short, because it mainly exerts the inoculation effect by stimulating the generation of autogenous nuclei. Long-term heat preservation at high temperature will weaken the concentration fluctuation and energy fluctuation through diffusion, which will lead to the gradual reduction of authigenic nuclei. Barium is a good inoculant element, it generates ionic barium dicarbide, which is relatively stable. In addition, its specific gravity is larger than that of calcium, it has a smaller vapor pressure, and the decay time can be prolonged. It is a promising inoculant. Aluminum, titanium, zirconium and cerium have strong deoxidation ability except that their own carbides can be used as crystal nuclei. They further deoxidize molten iron, reduce the combination of oxygen and calcium, create favorable conditions for the combination of calcium and carbon, promote the formation of calcium dicarbide nuclei, and protect calcium dicarbide from functioning for a longer period of time.

(1) The amount of inoculant added in ductile iron is generally higher than that in gray cast iron; (2) If the pouring time of the molten iron after inoculation treatment is long, the addition amount should be increased due to inoculation decline; (3) Thin-walled castings are prone to white mouth, and the amount of inoculant added should be increased accordingly;