The most significant difference between high silicon nodular cast iron and ordinary nodular cast iron is the high content of silicon. In ordinary Ferritic Ductile Iron, the content of silicon can reach 3.0%, but in High Silicon Ductile Iron, the content of silicon is higher. Silicon is an element to promote graphitization. It is known from the experiment that the content of silicon element in high silicon nodular cast iron has a certain range. The content of silicon is generally controlled at 3.0% ～ 4.3%. Beyond this range, the performance of high silicon nodular cast iron will decline. Silicon can also play an anti-oxidation role in high silicon nodular cast iron, which can effectively form a thin oxide film on the metal surface to prevent the oxidation inside the metal. In addition to silicon, there are other chemical components in High Silicon Ductile Iron, including carbon, manganese, phosphorus, sulfur, etc. Sulfur and phosphorus are harmful elements, and both have anti graphitization effect. Although phosphorus does not affect the spheroidization of High Silicon Ductile Iron, segregation produces phosphorus eutectic. Severe segregation will sharply reduce the mechanical properties of High Silicon Ductile Iron, and the content is generally less than 0.03%. Sulfur is not only harmful, but also can cause poor nodularity of cast iron, resulting in many defects. Therefore, the sulfur content should be controlled less than 0.025%. Manganese is an element that promotes the stability of austenite and promotes the formation of pearlite. The matrix of High Silicon Ductile iron is ferrite, so the content of manganese is controlled less than 0.2%. Copper is an element that promotes the formation of pearlite, and it is very strong. The content of ferrite in high silicon nodular cast iron is ferrite, avoiding the formation of too much pearlite. Generally, the content of copper is less than 0.1%.

High silicon nodular cast iron is a kind of nodular cast iron formed by silicon solid solution strengthening ferrite matrix. Solution strengthening is to form a solid solution by dissolving some solute element to strengthen the metal, so as to increase the strength and hardness of solid solution. When the concentration of solute element is appropriate, the strength and hardness of material can be improved, High silicon nodular cast iron uses silicon solution strengthening to achieve the purpose of strength and toughness. The matrix structure is mainly composed of ferrite, and the content of pearlite is less than 5%, and the content of free cementite is also very low, less than 1%.

High frequency infrared multi-element analyzer can accurately measure the content of silicon, carbon, sulfur, manganese, phosphorus and other elements in ductile iron. Nanjing Nuojin high-speed analytical instrument factory is a professional high-tech enterprise which takes the lead in R & D, production, sales and after-sales service of high-speed analytical instruments in China. It can accurately analyze the contents of carbon, sulfur, manganese, silicon, phosphorus, chromium, nickel, molybdenum, copper, aluminum, titanium, vanadium, niobium, iron, rare earth, magnesium and other elements in ordinary carbon steel, cast iron, nodular iron, high, medium and low alloy steel, copper alloy, aluminum alloy, iron alloy, iron alloy and ore. It is an ideal choice for industrial production and scientific research.

Nanjing Nuojin high speed analytical instrument factory

October 13, 2017