接头碳化物带形成机制
(1. 西北工业大学 材料科学与工程学院，西安 710072；
2. 中国兵器工业七零研究所 增压器厂， 大同 037036)
摘 要: 采用摩擦焊接连接发动机涡轮增压器高温合金K418涡轮盘与调质钢42CrMo转子轴时， 其接头常会发生低应力破坏和表面缺陷， 拉伸断口外圈出现“光亮圆环”。 接头金相组织、 断口微观形貌及接头元素成分分析表明， 由于两种材料物理与化学性能的差异，焊接过程中发生了摩擦界面转移现象， 新形成的“次生摩擦面”诱导碳元素在其上聚集， 从而在高温合金一侧形成了一条沿着次生摩擦面分布的碳化物带， 导致接头的低应力破坏。
关键字: 摩擦焊接； 异种金属； 碳化物； 涡轮转子； 次生摩擦面
friction welding joint of superalloy K418 and steel 42CrMo
（1. School of Materials Science and Technology，
Northwestern Polytechanical University， Xi′an 710072， China；
2. Supercharger Factory， China North Engine Research Institute，
Datong 037036， China）
Abstract:The friction welding of the superalloy turbo disk and the steel rotor axial is a key technique of the engine manufacture. The lower stress destruction and surface defect are frequently occurred at welding joint. The outside of tension fracture surface appears as “bright cirque”. The microstructure， fracture surface and element distribution of joint were analyzed. The results show that because of the difference between the physical and chemical performances of the welded materials， the friction interface transforms from the interface between superalloy and steel to the interior of superalloy， and forms a “secondary” friction interface. The carbon enriches at the secondary friction interface at high temperature. During cooling， the carbide bond forms on the secondary friction interface of superalloy， resulting in the lower stress destruction of welding joint.
Key words: friction welding； dissimilar metal； carbide； turbo rotor； secondary friction interface
