In the national standard, the content of each element in the pig iron castings is less
In addition to pig iron, also contains carbon, silicon and manganese, phosphorus and sulfur and other elements. These elements have a certain influence on the performance of pig iron. Carbon (C) exists in two forms: one is in pig iron, free carbon (graphite cast iron), mainly in the cast iron, the other is the combination of carbon (Fe3C) mainly exists in the steel and iron, iron carbide, hard and brittle, low plasticity, appropriate content can improve the strength and hardness of cast iron, the iron content is too much, it is difficult to cut processing, steel-making pig iron causes poor cutting performance.
This is because the pig iron to reduce the sulfur melting point, so in some products, often with high phosphorus. However, the existence of phosphorus and iron increase of brittle iron, phosphorus content should be less good, sometimes in order to increase the mobility of phosphorus sulfur can reach 1.2%. (S): in the pig iron is the harmful element, make it a combination of iron and carbon, the iron hard brittle, iron sulfide and chemical synthesis of low melting point and iron, the brittle cast iron heat generated and reduce the mobility of liquid iron, iron sulfur Gu high not suitable for casting small pieces. The sulfur content in the cast iron casting provisions shall not exceed 0.06% (except iron wheels).
Graphite is soft, low intensity, it can increase the performance of pig iron casting. The silicon (Si): to make pig iron contained in the graphite like carbon sequestration, can also reduce the air oxygen, casting, can improve the fluidity of molten pig iron to reduce the casting shrinkage, but silicon containing too much. It will be hard brittle cast iron. Manganese (Mn): can be dissolved in ferrite and cementite. In blast furnace refining iron, manganese content is proper, can improve the performance of pig iron casting and cutting performance of manganese in the blast furnace can also be harmful impurities and the formation of manganese sulfide sulfur, phosphorus (into the slag. P): belongs to the harmful elements, liquidity but can make the increase of iron phosphorus,
