某燃油直通管接头的65Mn钢弹簧垫圈在安装不到两个月后，其侧面发生大面积锈蚀。通过宏观观察、金相检验、扫描电镜及能谱分析、硬度试验和开路电位试验等方法，分析了弹簧垫圈锈蚀的原因。结果表明：弹簧垫圈侧面的锈蚀产物主要为Fe₂O₃；弹簧垫圈锈蚀的主要原因是其在装配过程中与平垫圈和锁紧螺母之间发生摩擦，导致其表面氧化膜部分发生脱落，在气密性检查残留的皂液环境中，造成了弹簧垫圈的锈蚀。

Less than two months after installation of the 65Mn steel spring washer of a fuel through pipe joint, a large area of rust occurred on its side. Through macroscopic observation, metallographic inspection, scanning electron microscope and energy spectrum analysis, hardness test and open circuit potential test, the reasons for corrosion of spring washer were analyzed. The results showed that the corrosion products on the side of spring washer was mainly Fe₂O₃. The main reasons for corrosion of spring washer were the friction between the flat washer and the lock nut during the assembly process, which caused the oxide film on its surface to fall off. In the soap liquid environment left by the air tightness check, the spring washer was corroded.