现有激光表面熔覆技术大多只能在水平或小角度倾斜基面上进行,基于"光束中空、光内送粉"技术,解决了喷头空间倾斜送粉过程中粉束汇聚性差的难题,通过控制激光机器人夹持送粉喷头做大角度连续变姿态运动,喷头轴线方向始终与曲面法向重合,实现了在大角度倾斜曲面上激光熔覆均匀涂层。分析了曲面熔池受力情况、不同倾角曲面熔池形状以及扫描路径对熔道成形的影响,通过控制准直气速度使熔道宽度保持稳定,并对不同倾角处曲面熔覆形貌及组织性能进行了详细分析。结果表明,各倾角处曲面熔覆层厚度均匀,截面组织致密,无明显裂纹和气孔,曲面熔覆层与基体结合良好。为实现金属零部件复杂空间曲面修复提供了新方法。
Laser cladding technology is based on horizontal or small-angle reference plane at present. The poor powder converging characteristic when the nozzle is inclined is solved by adopting the technology of"hollow laser beam and internal powder feeding". The variable postures moving of nozzle with larger inclined angle are realized by controlling laser processing robot. The axis direction of powder feeding nozzle is always coincident with curved surface normal direction. The uniform coating on the curved surface with large inclined angle are accomplished.The forces of molten pool on the curved surface are analyzed. The influences of different inclined angles on molten pool size and scanning path on cladding layer are also analyzed. The width of cladding layer keep stable by controlling the collimating gas rate, and the morphology and performance of curved surface cladding layer with different inclined angles are investigated detailedly. The results show that the thickness of cladding layer is uniform,the section microstructure is dense without obvious cracks and pores and the cladding layer is combined well with substrate. A new method for repairing complex metal parts is provided.