某型排气阀阀座失效机理研究

Study on the Failure Mechanism of an Exhaust Valve Seat

针对某排气阀阀座外圆水槽断裂失效的问题,采用主机试验、数值模拟、金相检测以及材料化学分析的方法研究排气阀阀座断裂失效机理。结果表明:该型排气阀阀座结构设计合理,过盈量的设计参数值对结构强度的影响较小;失效阀座中的化学成分及硬度满足技术要求。阀座材料碳含量较高,经热处理以及液氮冷却安装后脆性增加是造成开裂的主要原因。减少材料中的碳含量,能有效解决排气阀断裂失效的问题。

Aiming at the problem of fracture and failure of the outer circular water tank of a certain exhaust valve seat,use host test,numerical simulation,metallographic detection and material chemical analysis methods to study its failure mechanism.The results show that the valve seat structure design of this type of exhaust valve is reasonable,the design parameter value of its interference has little effect on the structural strength;the chemical composition and hardness in the failed valve seat meet the technical requirements.The exhaust valve seat material has a higher carbon content,the increase in brittleness after heat treatment and liquid nitrogen cooling and installation is the main cause for its cracking.Reducing the carbon content in the material can effectively solve the failure of the exhaust valve.