硅元素对铁素体球铁曲轴硬度的影响规律

研完了稀土、锰和硅元素对冰箱压缩机铁素体球铁曲轴硬度的影响，并依据铁素体的固溶强化机理进行了理论分析。测试了球铁试样的力学性能，并观察了材料的金相组织。结果表明：影响铁素体球铁曲轴硬度的主要元素是硅。硅溶于铁素体（α-Fe）形成置换固溶体，造成晶格畸变，引起硬度提高。在试验范围内．铁索体球铁硅含量与其布氏硬度成正比关系。通过调整硅含量，控制曲轴的硬度达到140～160HB，满足了机加工对曲轴切削加工性的要求。

Influence of Silicon on Ferrite Hardness of Nodular Cast Iron for Crank Shaft

The effects of rear earth, manganese and silicon elements on ferrite hardness of nodular cast iron used for crank shaft were analyzed. Samples of ferrite nodular iron crank shaft were fabricated. Mechanical properties of samples were measured and microstructures of materials were observed. Silicon was the main element which dissolved into ferrite to form suhstitutional solid solution, and caused lattice distortion and increased haMness. Within the tested range, the silicon content of the ferrite nodular iron was linear with hardness. During production, the haMness range of the crank shaft might be controlled through adjusting the silicon contents of the molten iron. Thus the demand of machinability was satisfied.