柴油机排气阀杆断裂失效研究

On Fracture and Failure of Exhaust Valve Stem of Diesel Engine

本文对排气阀杆断裂进行了宏观断口分析、扫描电镜断口研究、金相观察及成份性能分析。研究表明;造成阀杆断裂主要是由于逆硬化现象产生的应力集中及组织遗传现象产生的粗大晶粒,致使阀杆出现的热疲劳断裂。

This article is devoted to the research on the macroscopic fracture analy- sis, scanning electron microscope fractographs analysis, metallography analysis, chemical analysis and mechanical properties analysis in the exhaust valve stems. It is shown that the fracture in exhaust valve stems is mainly of thermal fatigue caused by the stress con- centration from inversehardening and by the coarse grain from microstructural heredity.