Cu含量对QT600-10显微组织和力学性能的影响

Influence of Cu Content on the Microstructures and Mechanical Properties of QT600-10

QT600-10球墨铸铁主要用于差速器、凸轮轴等核心零部件,然而随着产品轻量化的快速发展,对QT600-10屈强比提出了更高要求。Cu有助于提升QT600-10的屈强比,但是在工厂生产条件下根据经验严格限定了Cu含量不超过0.2%(质量分数),这极大地影响了Cu对铸态QT600-10屈强比的调控作用。本文针对该经验参数的合理性开展研究,在稳定工厂生产条件下制备了具有不同Cu含量的铸态QT600-10球墨铸铁,并采用多种表征和测试手段对其组织形貌、元素分布、硬度及拉伸性能等进行分析。结果表明,0.2%(质量分数)Cu含量上限并不具有合理性,Cu含量提升至0.456%(质量分数)时对铸态QT600-10的显微组织不产生显著影响且不引发有害相变,同时提升了铸态QT600-10的屈强比和硬度,并保持较高的伸长率。

QT600-10 ductile iron is mainly used in core components such as differentials and camshafts.However,with the rapid development of lightweight products,higher requirements have been put forward for the yield ratio of QT600-10.Cu contributes to improving the yield ratio of QT600-10.Nevertheless,under factory production conditions,the upper limit of Cu content is empirically restricted to 0.2%(mass fraction),which severely restricts the tailoring effect of Cu on the yield ratio of as-cast QT600-10.In this paper,the rationality of this empirical parameter was studied by preparing as-cast QT600-10 ductile iron samples with different Cu contents under stable factory production conditions,and analysing the corresponding microstructure,elemental distribution,hardness and tensile properties via various characterization and testing methods.The results show that the empirical limit of 0.2%(mass fraction)Cu is not always rational,for no significantly effect on the microstructures of the as-cast QT600-10 and no harmful phase transitions are found with increasing the Cu content to 0.456%(mass fraction).Meanwhile,the 0.456%(mass fraction)Cu content increases the yield ratio and hardness of the as-cast QT600-10 while maintaining a high total elongation.The findings of this research will provide an experimental basis for optimizing the composition of as-cast QT600-10 ductile iron and controlling the quality of the on-site casting process.