Refinement of primary carbides and improvement of wear resistance of hypereutectic high chromium cast iron after modification

Abstract

The effect of the modification treatment on the refinement of primary carbides and wear resistance of 35% Cr-4.0% C hypereutectic high chromium cast iron (HHCCI) was investigated using the first-principles calculations, XRD, SEM, TEM, hardness tests, and wear tests. The addition of N elements to HHCCI refined the size of the M7C3 primary carbide from 13.25 ± 0.72 μm to 11.67 ± 0.33 μm under the effect of adsorption refinement. When the compound modification elements (N + Ti + V + RE-Mg) were added, the combination of adsorption refinement and heterogeneous nucleation refinement significantly reduced the carbide size to 5.35 ± 0.15 μm. The refinement of the M7C3 primary carbide can be attributed to two components: 1) the refinement of the heterogeneous nucleation of TiC and VC. 2) the combination of N, Ti, and V with the M7C3 preferred growth surface (0001) resulting in the refinement by adsorption and reduce the size of the primary carbide. The hypereutectic high chromium cast iron after the compound modification exhibited excellent wear resistance. Under dry sliding wear condition, Compared with the unmodified sample, the wear resistance increased by 75%. Under corrosive wear conditions, the wear resistance is increased by 98.1%.

Keywords

• Hypereutectic high chromium cast iron
• Modification
• Primary carbide
• First principle calculation
• Wear resistance