节流阀失效分析

Analysis on Throttle Valve Failure

某型节流阀的阀片,材料为20CrMo钢,经渗碳、淬硬处理,最终检验时发现有1件失效。检测了失效阀片的外观、化学成分、显微组织、非金属夹杂物和表层硬度分布,并与正常的阀片作了比较。结果表明:节流阀阀片失效是由于热处理工艺和操作不当,导致残留奥氏体较多所致。

From final examination it was found that one valve clack of a certain throttle valve, made of 20CrMo steel and carburized and hardened, was failure to be used. The failed valve clack was tasted for appearance, chemical composition , microstructure , nonmetallic inclusion , and hardness profile , and compared with those of the normal valve clack. The result indicated that the valve clack failure was attributed to more retained austenite which arose from improper heat treating process and operating.