Conventional elements impact on the performance of cast iron - bearing knowledge

Carbon ( C) : in the cast iron exist in two forms, one is free carbon ( Graphite) , mainly exists in cast iron, the other is a compound carbon ( Iron carbide) , mainly exists in steelmaking pig iron, iron carbide hard and brittle, low plasticity, appropriate content can improve the strength and hardness of the cast iron, the content is too much, then make the cast iron is difficult to cut cut processing, that is the reason why steelmaking pig iron cutting performance is poor. Graphite is soft, low intensity, it can increase the cast iron casting performance. Silicon ( Si) : to cast iron contains carbon separation for the graphite shape, can go to oxygen, can also reduce the air cavity casting, can improve the liquidity of molten iron, reduce the shrinkage of casting, but too much containing silicon, will also make the cast iron hard brittle. Manganese ( Mn) : soluble in ferrite and cementite. In the blast furnace refining pig iron, manganese content, appropriate can improve the performance and cutting performance, cutting cast iron casting of manganese in the blast furnace can also be harmful impurities and sulphur manganese sulfide formation, into the slag. Phosphorus ( P) : belongs to the harmful elements, but phosphorus can increase the liquidity of molten iron, this is because the reduced sulfur melting of cast iron, so often of high phosphorus content in some products. However, the presence of phosphorus and iron increase hard brittle, fine iron phosphorus content should be less, sometimes in order to increase liquidity, phosphorus content can reach 1. 2%. Sulfur ( S） : in the cast iron is a harmful element, it makes the combination of iron and carbon, iron hard brittle, and synthesis of low melting point of iron sulfide and iron, pig iron to produce hot brittleness and reduce the liquidity of iron liquid, despite high sulfur is not suitable for casting of cast iron pieces. Casting cast iron of sulfur content in the provisions shall not be more than 0. 06%