At present, the chemical composition of the mainstream high chromium cast iron at home and abroad are: carbon 2.4% – 3.6%, chromium 15%, alloy Mo 2%, Cu 1%
We adjust the chemical composition of high chromium cast iron as follows:
Carbon, with low carbon design, aims to further improve toughness
Chromium, reduce chromium content, and save chromium to the maximum extent under the condition of ensuring the formation of main anti-wear structure (Cr7C3)
Low alloyed, save Mo, Cu and other metals to reduce manufacturing cost
Molybdenum is mainly used to refine the matrix, stabilize the pearlite, refine the carbide, and improve the electrode potential and corrosion resistance of the matrix
Nickel is the element of austenite formation. Its main function is to improve hardenability, prevent transformation of austenite to pearlite, and promote the formation of martensite. In addition, nickel can also improve the electrode potential of the matrix and improve corrosion resistance, but it is uneconomical to add more, and a small amount will play a role
Rare earth compound modifier, rare earth is a rich mineral resource in China, adding a small amount of rare earth has a significant effect. The role of rare earth is deoxidization, desulfurization, inhibiting the segregation of inclusions in the microstructure grain boundary, improving the grain boundary condition. Because rare earth element segregation, adsorption in the preferred growth direction of carbide, the growth of carbide is inhibited, so that it becomes even and isolated, However, other modified elements can form dispersed carbon and nitrogen compounds, which can prevent grain growth and refine grains. Therefore, the re composite modifier can change the microstructure of the material, improve the hardness and impact toughness of the material
Because of the decrease of carbon content, the microstructure of the designed material is closer to that of steel rather than iron, so the designed wear-resistant material is named high chromium cast steel. Comparison of chemical composition between high chromium cast steel and common high chromium cast iron.