发动机排气门锥面局部出现麻坑的原因

Pitting Analysis of the Local 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发动机锥面局部有麻坑的发动机排气门进行了分析。结果表明:因摇臂与排气门杆部端面接触点不恰当导致气门不旋转,造成排气门杆部偏磨和排气门锥面局部漏气,最终使排气门锥面局部出现麻坑。

Analysis of the exhaust valve seat with local pitting was conducted by means of macrostructure and microstructure examination, chemical composition analysis and hardness test. The results indicate that the rocker was not well contact with the valve top of the exhaust valve. It caused the valve could not rotate,which resulted in the eccentric wear of the stem and local leakage of the seat of the exhaust valve. Finally the exhaust valve seat appeared pitting at local position.