QT500-7球墨铸铁拉伸试样断口异常分析  

Abnormal Analysis on Fracture of QT500-7 Ductile Iron Tensile Specimen

作　　者：方元 FANG Yuan(Wuhu Bethel Automobile Safety System Co.,Ltd.,Wuhu 241000,China)

机构地区：[1]芜湖伯特利汽车安全系统股份有限公司,芜湖241000

出　　处：《理化检验（物理分册）》2020年第3期36-38,60,共4页Physical Testing and Chemical Analysis(Part A:Physical Testing)

摘　　要：拉伸试验中QT500-7球墨铸铁拉伸试样断裂后断口存在颜色较深的异常区。通过宏观观察、化学成分分析、金相检验、力学性能测试等方法对异常区形成原因进行了分析。结果表明:球墨铸铁铸造过程中局部石墨球化不良或球化衰退造成了该区域显微组织中有大量的蠕虫状石墨,导致球墨铸铁拉伸试样断口异常,这严重降低了球墨铸铁材料的屈服强度、抗拉强度和断后伸长率等力学性能。In the tensile test,the fracture surface of QT500-7 ductile iron tensile specimen had dark abnormal area on the fractured specimen.The causes of the abnormal area were analyzed by means of macroscopic observation,chemical composition analysis,metallographic examination and mechanical property test.The results show that there were a lot of vermicular graphite in the microstructure of ductile iron caused by the poor spheroidization or the degradation of spheroidization during the casting process,which led to the abnormal fracture of ductile iron tensile specimen,which seriously reduced the mechanical properties of ductile iron such as yield strength,tensile strength and elongation after fracture.

关 键 词：球墨铸铁 蠕虫状石墨 球化不良 力学性能 

分 类 号：TG143.5[一般工业技术—材料科学与工程]