Nb含量对过共晶高铬铸铁微观组织和力学性能的影响

Effect of Nb Content on Microstructure and Mechanical Properties of Hypereutectic High Chromium Cast Iron

摘要: 通过添加Nb元素来细化过共晶高铬铸铁中的初生碳化物。研究了在空冷条件下Nb含量对过共晶高铬铸铁组织及性能的影响。结果表明，添加Nb元素可在合金中先形成Cr₂Nb，并作为M₇C₃相形核的核心，提高M₇C₃的形核率，显著细化过共晶高铬铸铁中的初生碳化物，提高过共晶高铬铸铁的硬度。Nb添加量为1.5%时，试样硬度达到86.5 HRC。

Abstract: The primary carbide in hypereutectic high chromium cast irons（HCCIs） was refined by the addition of Nb during air cooling, and the influences of Nb content on the microstructure and mechanical properties of hypereutectic HCCIs in cooling condition were investigated. The results show that Cr₂Nb forms firstly in the alloy by Nb addition during the solidification process, increase nucleation rate and refine the proeutectic carbide, then increase the hardness of Nb contained hypereutectic HCCIs. The hardness reaches 86.5 HRC, when 1.5%Nb content is added.