Carbon is the main element in steel and plays a decisive role in the matrix structure of steel. A small amount of carbon is dissolved in ferrite, and the rest exists in the form of cementite. Carbon is the main element of strengthening, but in order to reduce the stress and brittleness of castings, the carbon content is set at 0.3% ~ 0.5%.
Silicon has the characteristics of strongly inhibiting carbide precipitation in the process of bainite transformation, so that there is no carbide precipitation in bainite, Si can stabilize and refine austenite, increase the segregation of C and Mn, inhibit the nucleation and growth of bainite, and move the C-curve of the alloy to the right.
The main function of manganese in cast wear-resistant steel is deoxidation, neutralizing the harmful effect of sulfur and preventing defects such as hot crack in castings. Manganese can be dissolved in a small amount of ferrite and has the effect of solid solution strengthening, so as to improve the yield strength and tensile strength of steel, and basically do not reduce the plasticity and toughness of steel. Manganese can increase hardenability and uniformity of section hardness. It is the main element to ensure self hardening as cast. Combined with silicon, it can improve the strength and hardness and maintain high impact toughness.
Nickel is dissolved in ferrite or pearlite to strengthen the solid solution, which can improve the strength and hardness of cast iron.
Chromium is one of the most strongly stable and carbide forming elements. Chromium can improve the wear resistance and hardenability of the matrix.
Number | C | Si | Mn | Ni | Cr |
1 | 0.38 | 1.0 | 0.9~1.2 | 0.5~0.7 | 1.5 |
2 | 0.38 | 1.5 | 0.9~1.2 | 0.5~0.7 | 1.5 |
3 | 0.38 | 2.0 | 0.9~1.2 | 0.5~0.7 | 1.5 |
4 | 0.43 | 1.0 | 0.9~1.2 | 0.5~0.7 | 1.5 |
5 | 0.43 | 1.5 | 0.9~1.2 | 0.5~0.7 | 1.5 |
6 | 0.43 | 2.0 | 0.9~1.2 | 0.5~0.7 | 1.5 |
7 | 0.48 | 1.0 | 0.9~1.2 | 0.5~0.7 | 1.5 |
8 | 0.48 | 1.5 | 0.9~1.2 | 0.5~0.7 | 1.5 |
9 | 0.48 | 2.0 | 0.9~1.2 | 0.5~0.7 | 1.5 |
To sum up, according to the service conditions of the shovel teeth, the composition design is listed in the table.