Metallurgy Failure Analysis for an Early Fracture Engine Intake Valve Made of 85Cr18Mo2V
By means of analysis technique such as scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS), and transmission electron microscopy (TEM), deep metallurgy failure analysis for an early fracture engine intake valve made of the martensite material of 85Crl8Mo2V was performed through macroscopical and microcosmic as well as chemical composition angles. According to the result of SEM, this valve belonged to fatigue fracture. The crack sources of dense micro-holes near the surface of intake valve and SiO2 impurity are the direct reasons to cause the valve failure. The EDS analysis for the fatigue source region approved that superfluous Si, O and Al impurity existed. The TEM observation of the slice cut from the region closing to the fracture surface showed that deep areas near the surface of valve were oxidized severely. The material structure got brittle due to the generation of Fe3O4. Cracks will be produced in these oxidation areas under high cycle fatigue loading. Consequently, the synthetical action of various factors finally caused the fracture of valve.
intake valve fatigue fracture 85Crl8Mo2V failure analysis interior oxidation
Zhang Yubo Xu Binshi Wang Haidou Yang Daxiang Zhu Lina
National Key Laboratory for Remanufacturing, Academy of Armored Forces Engineering, Beijing 100072, China
国际会议
西安
英文
148-151
2011-05-11（万方平台首次上网日期，不代表论文的发表时间）