低温高韧性球铁的制备及其性能的研究

Preparation of High Toughness Ductile Iron at Low Temperature and Its Properties

合理选择了材料的化学成分、球化处理及热处理工艺,采用中频感应电炉熔炼铁液,制备出低温高韧性球墨铸铁。结合金相显微镜、万能材料拉伸机、扫描电镜等分析方法对它进行了研究。结果表明,低温高韧性球墨铸铁的组织结构由铁素体及石墨球组成;其抗拉强度均大于400 MPa,断后伸长率均大于24%,拉伸试样断口的微观特征呈韧性断裂。在-20℃冲击韧度最小值达16 J/cm2,均值大于17 J/cm2,可以满足球墨铸铁件在高寒地区的使用要求。

Chemical composition, spheroidizing and heat treatment process were reasonably chosen. High toughness ductile iron at low temperature was prepared by using intermediate frequency induction electric furnace, which was studied by optical microscope, universal material testing machine and scanning electron microscope, etc. The results show that the microstructure of high toughness ductile iron at low temperature consists of ferrite and graphite nodule. The tensile strength is higher than 400MPa, the elongation rate is higher than 24%, the fracture micro-characteristic of the tensile sample was ductile rupture. The minimum impact toughness of the ductile iron at -20℃ reaches 16J/cm2, the average impact toughness of ductile iron is higher than 17J/cm2, so that it can meet the requirements of ductile iron in the very frigid regions.