凸轮轴工作面点蚀坑冷焊再制造工艺与性能研究

Investigation of cold-welding remanufacturing process and performance of camshaft working surface′s pitting corrosion

凸轮轴在服役过程中工作表面容易发生磨损,严重影响机器的正常运转。采用冷焊设备修复凸轮轴工作表面点蚀坑,通过金相显微镜观察修复区域显微组织,利用X射线残余应力测试仪、硬度测试仪表征补焊点周围的残余应力分布以及硬度分布规律。结果表明,补焊点与基体结合良好,从奥氏体中析出的碳化物弥散分布于基体组织中,补焊点位置呈现出最小的残余应力以及最小的硬度值,补焊点对于残余应力以及硬度的影响维持在补焊点中心4 mm以内。经冷焊修复后的凸轮轴满足使用性能要求。

The working surface of a camshaft is easily worn during service,thus seriously affecting the normal operation of the machine.The pitting areas on the working surface of the camshaft were repaired using cold-welding equipment.A metallographic microscope was used to observe the microstructure of the repaired area,and the residual stress distribution and hardness distribution around the repaired areas were determined using an X-ray residual stress tester and a hardness tester,respectively.The results show that the repair welding spot is well combined with the matrix,the carbides precipitated from austenite are dispersed in the matrix structure,the position of the repair welding spot presents the minimum residual stress and the minimum hardness value,and the influence of the repair welding spot on the residual stress and hardness is maintained within around 4 mm of the repaired areas.The camshaft repaired via cold welding meets the service performance requirements.