含镍量对QT400-18L低温冲击韧度的影响  

Effect of Ni Content on Impact Toughness of QT400-18L at Low Temperature

作　　者：路焱[1] 刘向东[1] 李勇[2] 李进福[1] 乌迪[1] 吕凯[1] 

机构地区：[1]内蒙古工业大学材料科学与工程学院,内蒙古呼和浩特010051 [2]呼和浩特铁路局集宁工务段铸造厂,内蒙古集宁012000

出　　处：《铸造技术》2006年第12期1342-1345,共4页Foundry Technology

摘　　要：球墨铸铁在低温下常发生脆断，限制了其在工程上的应用，采取适当措施，进行合金化和热处理控制组织，以解决球铁低温冲击韧度不足的问题。试验在球铁QT400—18L中加入0～110％的镍进行合金化并采用两阶段石墨化退火对铸件进行热处理；将无水乙醇与干冰在密封容器内按一定比例混合，模拟三种低温环境，将冲击试样放入，待试样达到预定温度后，测定其冲击韧度。分别测试试样在室温、-20℃、-40℃、-60℃条件下的冲击性能。试验结果表明，加入质量分数0．3％Ni的球铁，经热处理后具有良好的冲击韧度。在四种温度环境下，其冲击韧度αkv，分别可达到23．425J／cm^2、23、738J／cm^2、20．867J／cm^2和15．886J／cm^2。尤其在-40℃时，αkv〉12J／cm^2，可以满足球墨铸铁件在高寒地区的使用要求。Brittle failure of ductile iron at low temperature limits its application in engineering. Some measures such as alloying and heat treatment should be taken to change microstructure of ductile iron so as to improve impact toughness of QT400-18L at low temperature. QT400-18L were alloyed with 0- 1. 0wt% Ni addition, and then heat treated through two stage graphitisation. Three low temperature conditions were simulated using different formulation of mixture of absolute ethyl alcohol and dry-ice, The specimens were put into the container and hold for a certain time until they reached expected temperature, impact toughness of specimens were measured. The results show that excellent impact toughness of ductile iron can obtain with 0. 3wt% Ni addition and two-stage graphitization Impact toughness values αkv of the specimens reaches 23. 425 J/cm^2 at room temperature, 23.738 J/cm^2 at - 20 13, 20. 867 J/cm^2 at - 40 13 and 15. 886 J/cm^2 at - 60 13 respectively. Especially at -40 13, the impact toughness of ductile iron excess 12 J/cm^2 so that it can meet the requirements of ductile iron in the very frigid regions.

关 键 词：球墨铸铁 低温冲击韧度 合金化 石墨化退火 

分 类 号：TG113.25[金属学及工艺—物理冶金]