The usage of casting inoculants can promote graphitization, reduce the tendency of white mouth, improve the shape and distribution of graphite, increase the number of eutectic groups and refine the matrix structure. It has good effect in short time (about 5-8 minutes) ) after inoculation treatment.
Inoculants is mainly suitable for general conditions or late transient breeding in various situations. There is a wide variety of casting inoculants to treat the grey cast iron, following introduce several general types:
1.75 ferro silicon inoculant. It is the most commonly used inoculant, and the content of aluminum and calcium plays an important role in the inoculation effect. It has been reported that the ferrosilicon without aluminum and calcium has little or even no effect on the inoculation of grey cast iron. Generally think that , in the molten iron, aluminum and calcium will react with oxygen and nitrogen to be the compound with high melting point and to be the core of graphite crystal. What is more, after adding the inoculant, it will form the partial silicon-rich microdomains in molten iron which is advantage to the graphite precipitation.
For the 75 ferro silicon inoculant, the relevant US standards stipulate that the aluminum content is 0.75~1.75%, and the calcium content is 0.5%~1.5%. In China according to the GB/T 2272-1987 stipulate the 75 ferrosilicon in different content of aluminum, the max content of aluminum are 0.5%,1.0%,1.5% and 2.0%, the max content of calcium is 1.0%.
2. Silicon barium alloy inoculant. It is one type of inoculant which can be suitable for grey iron and ductile iron, can promote ‘A”-type graphite to be whole graphite ball. It can be nucleation in wider temperature range, owe strong nodulizing and recession-resistant ability, can prevent the tendency of castings cutting whiten efficiently. Deoxy effectiveness will be more thorough than other deoxy ferroalloy, and the quantity adding into is 35%-55% of 75 ferrosilicon.
The silicon barium alloy contain 20~30% barium as the inoculant can obviously reduce the tendency of white mouth for grey cast iron, and can lengthen the time of inoculant effect to be 30 minutes, especially suitable for the large casings.
There are also other inoculants such as the ferrosilicon with strontium, the ferrosilicon with barium, silicon calcium alloy, carbonaceous inoculant and etc. In general, the most widely used casting inoculant is 75 ferrosilicon. Anyang Huatuo Metallurgy Co.,Ltd has in the manufacture and export of casting inoculants for more than 20 years, we own the advance equipment and professional team, adhere to the “Honest Management, Quality First, Mutually Beneficial”, trust us can provide best service and product, any need just leave your message.