为提高柴油机配气系统的可靠性与耐久性，对于工作条件恶劣的进、排气门座，大多采用合金铸铁材料制做。但是随着机器运转时间的增长，往往会发生气门座松动的故障，从而导致柴油机功率下降、排气冒烟、曲轴箱窜气及缸盖部分出现敲击声等的不良后果，严重时发动机停止运转。1气 In order to improve the reliability and durability of the diesel engine gas distribution system, most of the inlet and exhaust valve seats with poor working conditions are made of alloy cast iron. However, with the increase of the running time of the machine, the loosening of the valve seat often occurs, which leads to the adverse consequences of the decline of the power of the diesel engine, the emission of smoke, the blow-by of the crankcase and the sound of knocking on the cylinder head portion. In severe cases, the engine stops Run. 1 gas