低温退火中保温时间对QT500球墨铸铁微观组织及力学性能的影响  

Effects of Holding Time on Microstructure and Mechanical Properties of QT500 Ductile Iron during Low Temperature Annealing

作　　者：温长浩 修俊杰 WEN Changhao;XIU Junjie(College of Nuclear Equipment and Nuclear Engineering,Yantai University,Yantai 264000,China)

机构地区：[1]烟台大学核装备与核工程学院,山东烟台264000

出　　处：《热加工工艺》2024年第22期105-108,共4页Hot Working Technology

基　　金：山东省自然科学基金项目(ZR2016EEP14,ZR2015EQ014)。

摘　　要：将铁素体-珠光体混合基体球墨铸铁(QT500)进行740℃低温退火,分别保温2、4、6 h,用金相显微镜和维氏显微硬度计检测保温时间对球墨铸铁试样微观组织与力学性能的影响。结果表明:随着保温时间的增长,球墨铸铁试件出现脱碳现象,基体组织从铁素体-珠光体混合基体逐渐向铁素体基体转变,并且出现铁素体晶粒粗化现象。保温时间2 h,球墨铸铁的试件硬度值最大为197 HV。保温时间加长,硬度开始逐渐下降,在保温时间6 h的时候,球墨铸铁试件的硬度为138 HV低于原始球墨铸铁试件的硬度148 HV。因此,通过对低温退火热处理中保温时间的改变,可以得到所需性能的球墨铸铁材料。The ferrite-pearlite mixed matrix nodular cast iron(QT500)was annealed at 740℃and held for 2 h,4 h and 6 h,respectively.The effects of holding time on the microstructure and mechanical properties of the nodular cast iron samples were detected by metallography microscope and Vickers microhardness tester.The results show that with the increase of holding time,the decarbonization phenomenon occurs in ductile iron specimens,and the matrix structure gradually changes from ferrite-pearlite mixed matrix to ferritic matrix,and the ferrite grain coarsening phenomenon occurs.The maximum hardness of nodular cast iron is 197 HV after holding for 2 h.When the holding time is prolonged,the hardness begins to decrease gradually.When the holding time is 6 h,the hardness of nodular cast iron specimen is 138 HV,lower than that of original nodular cast iron specimen 148 HV.Therefore,ductile iron materials with desired properties can be obtained by changing the holding time in the low temperature annealing heat treatment.

关 键 词：球墨铸铁 低温退火 石墨球 基体组织 力学性能 

分 类 号：TG156.2[金属学及工艺—热处理]