接頭碳化物帶形成機(jī)制
(1. 西北工業(yè)大學(xué) 材料科學(xué)與工程學(xué)院，西安 710072；
2. 中國(guó)兵器工業(yè)七零研究所 增壓器廠， 大同 037036)
摘 要: 采用摩擦焊接連接發(fā)動(dòng)機(jī)渦輪增壓器高溫合金K418渦輪盤與調(diào)質(zhì)鋼42CrMo轉(zhuǎn)子軸時(shí)， 其接頭常會(huì)發(fā)生低應(yīng)力破壞和表面缺陷， 拉伸斷口外圈出現(xiàn)“光亮圓環(huán)”。 接頭金相組織、 斷口微觀形貌及接頭元素成分分析表明， 由于兩種材料物理與化學(xué)性能的差異，焊接過(guò)程中發(fā)生了摩擦界面轉(zhuǎn)移現(xiàn)象， 新形成的“次生摩擦面”誘導(dǎo)碳元素在其上聚集， 從而在高溫合金一側(cè)形成了一條沿著次生摩擦面分布的碳化物帶， 導(dǎo)致接頭的低應(yīng)力破壞。
關(guān)鍵字: 摩擦焊接； 異種金屬； 碳化物； 渦輪轉(zhuǎn)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
