增/减材复合加工316L宏观形貌和残余应力试验

为了研究激光功率P、送粉速率f和扫描速度v_f对熔覆层宏观质量的影响，采用正交试验进行激光熔化沉积的单层单道成形试验研究.以熔覆层的形状系数ξ为评价指标，通过极差分析获得P，f和v_f对几何形貌影响的主次顺序.结果表明:在一定工艺参数范围内，f对熔覆层ξ的影响最大；最佳工艺参数组合是P，f和v_f分别为1kW，0.7g/min和600mm/min.利用X射线衍射法对增/减材复合制造316L不锈钢薄壁圆环表面残余应力的分布进行了试验研究.结果表明:试样表面的顶部和底部是拉应力，中间部分是压应力；铣削加工可以消除一部分残余应力.

Experiment on the Macro-morphology and Residual Stress of 316L by Hybrid Additive and Subtractive Manufacturing

In order to investigate the influence of laser power (P)， powder feeding rate (f) and scanning speed (v_f) on the macroscopic quality of cladding layers during the laser melting deposition， the orthogonal experiment was conducted to study the single pass laser cladding layer. The shape factor (ξ) was used as the evaluation index. The influence rule of P， f and v_f on the geometry morphology was concluded and the range analysis was adopted. The results indicate that f has the greatest influence on the shape factor ξ. The optimized process parameters of P， f and v_f are 1kW， 0.7g/min and 600mm/min， respectively. The superficial residual stresses in the thin-wall ring specimen of 316L by hybrid additive and subtractive manufacturing were measured by the X-ray diffraction method. The measurement results showed that the top and bottom of the samples are tensile stresses and the middle part is compressive stress. Moreover， the milling process can release part of the residual stress.