激励磁场下等离子喷焊再制造熔覆成形机理及表面质量评定

The emphasis on the surface remanufacturing technologies has been changed from dimension and performance recovery of remanufactured parts to higher requirement of quality and reliability. As one of the important techniques in surface remanufacturing, plasma spray welding still has many problems: unstable process quality, coarse grains in cladding layer, and hard to assess the recovery quality. Therefore, plasma spray welding demands new process control and surface quality evaluation method, which has also become one of the urgent problems in surface engineering. In this project, the integrated researches on forming process control of plasma spray welding and its surface quality inspection under the excitation of applied magnetic field will be carried out. The experimental system for forming and testing under the excitation of applied magnetic field will be established. The mechanism of applied magnetic field acting on plasma arc and weld pool will be illuminated, as well as the coupling mechanism of heat/force/magnetism during the process of solidification. The control method of stability molding for weld pool and the metal magnetic memory evaluation of thermal damage for spray welding cladding layer will be established. The performance of cladding layer of remanufactured parts in service will also be discussed. Finally, the quality control, evaluation method and detection system for plasma spray welding of ferromagnetic parts in remanufacturing will be established, in order to provide a theoretical basis for the industrial application. The research of this project not only can provide a foundation for process control and surface quality evaluation of surface additive remanufacturing for ferromagnetic materials, but also has great significance for improving the service safety and reliability of remanufactured products, promoting development of remanufacturing industrialization and realizing green manufacturing in industry.

表面再制造技术领域的重点研究问题已由恢复尺寸与性能转变为高质量与高可靠性保障。作为表面再制造修复的重要技术之一，等离子喷焊技术仍存在工艺质量不稳定、熔覆层晶粒粗大、修复质量评估困难等诸多问题，亟待研究其新型工艺控制及表面质量评定方法。本项目拟开展激励磁场作用下的等离子喷焊再制造熔覆成形工艺控制与质量检测一体化研究，阐明激励磁场对等离子弧与喷焊熔池区域的作用机理以及凝固过程中的热/力/磁耦合作用机制，建立等离子喷焊熔池稳定成型控制方法与熔覆层损伤的金属磁记忆量化评估方法；并开展再制造零件等离子喷焊熔覆层的服役性能研究，构建等离子喷焊再制造熔覆层质量控制与评定方法和检测体系，为其工业应用奠定理论与技术基础。项目的研究不仅能够为铁磁性材料表面增材再制造工艺控制及表面质量评定提供方法与应用支撑，而且对提高再制造产品服役安全性、促进再制造工程产业化发展、实现我国制造业绿色化具有重要意义。

再制造修复的重点研究问题已由恢复零部件的尺寸与性能转变为再制造产品的高质量与高可靠性保障。作为表面再制造修复的重要技术之一，等离子喷焊技术仍存在工艺质量不稳定、熔覆层晶粒粗大、修复质量评估困难等诸多问题，亟待研究其新型工艺控制及质量评定方法。本项目围绕激励磁场作用下的等离子喷焊再制造熔覆成形工艺控制与质量检测一体化，采取理论研究与实验验证相结合、基础研究与关键技术应用并行的方式，从激励磁场对等离子喷焊熔池作用机理及工艺参数优化方法、热/力/磁多场作用下的磁记忆信号产生机理、等离子喷焊熔覆层损伤状态的量化表征及服役状态检测方面开展深入研究。搭建了激励磁场作用下的等离子喷焊再制造熔覆成形工艺实验平台，开展了激励磁场对等离子喷焊熔池作用机理研究，发现一定条件下可减少熔覆涂层晶粒尺寸14%，提高硬度17%；基于流体/传热/电动力学建立熔池传热传质数值模型，表明横向磁场会抑制熔池流动；采用正交实验法优化工艺参数并应用于典型零部件的再制造修复。通过热/力/磁多物理场耦合条件下的有限元仿真以及实验观察，研究了磁记忆信号在磁场、应力及应力集中、温度、几何缺陷等因素作用下的变化规律，修正了经典J-A模型，建立了损伤及缺陷的磁记忆信号产生机理。开展了等离子喷焊熔覆层的应力、残余应力、动态载荷的磁记忆量化表征研究，研究了再制造零部件的摩擦磨损、承载、疲劳及断裂状态的损伤检测，建立了损伤状态的量化表征及服役状态检测方法，将磁记忆检测方法扩展到裂纹萌生-扩展-断裂阶段的检测，实现了亚微米级裂纹的检测。项目的研究不仅能够为铁磁性材料表面增材再制造工艺控制及表面质量评定提供理论方法与应用技术支撑，而且对提高再制造产品服役安全性、促进再制造工程产业化发展、实现我国制造业绿色化具有重要意义。