二次孕育及终硅量对铸态铁素体球墨铸铁组织性能的影响

Effect of Last-Silicon Content on Microstructure and Mechanical Properties of Ferrite Ductile Iron Obtained by Secondary Inoculation

将铸态球墨铸铁经退火处理生产铁素体球墨铸铁的工艺复杂、周期长。本研究进行了调整终硅量及采用二次瞬时孕育处理工艺直接得到铸态铁素体球墨铸铁的试验。结果表明，采用稀土镁球化剂和硅铁孕育剂，对铁液进行立即孕育、立即浇注的瞬时孕育处理，并控制终硅量为2.95％～2.99％，可直接获得铁素体球墨铸铁，石墨球径仅为0．019～0．017mm，球化级别提高至3～2级，铁素体量多达88．4％～94．7％，力学性能完全达到国家标准。

At present,the fabricating of ferrite ductile iron by heat treatment exhibits some problems such as complex process and long production period.In this paper,the ferrite ductile iron was obtained by secondary instantaneous inoculants and the effect of last-silicon content on its microstructure and properties were investigated.The results show that by controlling the ferrite ductile iron with final silicon content 2.95~2.99%,the graphite size is 0.019~0.017mm in diameter.The graphite nodularization degree increasing up to 2~3 grades with ferrite content of 88.4~94.7% can be directly produced by the instantaneous inoculants and casting.The mechanical properties of ferrite nodular cast iron agree with the requirement of the national-specified standard.