锥面氮化排气门台架试验出现凹坑分析

Pit Analysis of the Nitriding Exhaust Valve Seat of Engine

采用宏观和微观检验、化学成分分析和硬度测试等方法对锥面有凹坑的氮化排气门进行了分析。结果表明:因气门锥面氮化层次表面存在脆性的脉状组织,在气门锥面与座圈配合接触时,氮化层剥落形成凹坑。

Analysis of the nitriding exhaust valve seat with pitting was conducted by means of macroexamination and microstructure examination, chemical composition and hardness test. The results indicate that there is brittleness nervation structure at the nitriding valve seat hypo-surface, when the valve seat contacted with the seat, the nitriding layer flaked off, finally there are pit at the valve seat.