Spherical clad sand casting

Sulfur is a harmful element in cast iron. It is completely dissolved in the ferrofluid in the form of iron sulfide, which can reduce the solubility of carbon in iron (1% sulfur can reduce 0.5% points, characteristics and the form of existence are determined by the content of manganese and other elements in cast iron.

In addition, when there is a large amount of sulfate in the ferrofluid, the recyclability of the ferrofluid is reduced, leading to disadvantages such as poor shrinkage performance and easy cracking. Thus, the sulfur content in gray cast iron is generally limited to 0.1 - 0.12% below. Phosphorus has little effect on the graphitization of cast iron. When the phosphorus content in the ferrofluid reaches 1%, phosphorus and silicon can offset the carbide point of cast iron, so that the carbide point carbon content in the ferrofluid is reduced by 0.3%.

Castings produce slag, porosity and other defects tend to significantly reduce the trend of fusion die precision casting cylinder plug in production practice of cast iron containing high levels of phosphorus. Phosphorus can also reduce the liquid phase line temperature, improve the flow, which is conducive to fusion die precision casting joints to obtain a complete casting, especially in the casting of thin-walled parts, phosphorus content of up to 0.5%-0.8%. In order to improve the wear resistance of some cast iron, phosphorus content up to 0. High phosphorus cast iron is called 6% or more, and sometimes add some phosphorus purposely, such as machine beds, cylinder liners, pistons, etc.