传统的轨道交通铸件通常采用低牌号(QT400~QT600)球墨铸铁件。 本文主要研究高牌号的等温淬火球墨 铸铁QT800-10 轨道交通壳体铸件。 使用MAGMA模拟软件对轨道交通壳体铸件进行铸造工艺设计，通过增加冷铁的 方式对工艺进行优化。 采用金相、硬度和抗拉强度等测试方法，研究了不同合金元素对铸件组织和性能的影响。 结果表 明，加入3.65%C、2.52%Si，0.38%Mn 和 0.44%Cu 并同时加入 0.15%(质量分数)含铋孕育剂试样的抗拉强度、屈服强度、 延伸率达到最好状态。 经等温淬火处理后，铸件性能提升，达到客户标准要求。

 Conventionally, rail transit castings have been fabricated from low-grade ductile iron (QT400~QT600). This paper focused on the research and development of rail transit housing castings made of high-grade austempered ductile iron (QT800-10). The process design of rail transit housing casting was carried out via the simulation software MAGMA and optimized via the addition of chills. Through microstructure examination, hardness testing, tensile strength testing, and other methods, the influence of different alloying elements on the microstructure and properties of the casting was investigated. The research results indicate that when the alloy composition is 3.65 wt.% C, 2.52 wt.% Si, 0.38 wt.% Mn, and 0.44 wt.% Cu, along with 0.15 wt.% bismuth-containing inoculant, the tensile strength, yield strength, and elongation of the sample reach peak values. After austempering, the casting properties are enhanced, meeting the standard requirements of customers.