Inconel 617 Ni-based superalloy sheets were joined using a laser-welding process. The welding experiments were conducted on four different welding positions (i.e., flat, horizontal, vertical-up, and vertical-down), using two sets of welding parameters with different heat inputs. Then, the geometry, internal defects, mechanical properties, and molten-pool dynamics of the laser joints were evaluated. The results showed that, when using high-heat input parameters, the welding position has an obvious effect on the laser weld quality. The top surface of the flat weld and the root surface of the vertical-down weld are both slightly concave. Moreover, the horizontal weld and vertical-down weld have serious keyhole-induced porosity defects, which lead to relatively worse mechanical properties. The analysis shows that the stability of keyhole differs for different welding positions; keyhole-induced porosity is easily generated in the horizontal and vertical-down positions. Moreover, solid metal blocks escape routes of the bubbles, resulting in more serious porosity for these welding positions. However, when using low-heat input parameters, the welding position has less influence on the laser weld quality because there is less molten metal, which makes the keyhole more stable in different welding positions.

使用激光焊接工艺连接Inconel 617 Ni基高温合金板。使用两组具有不同热输入的焊接参数，在四个不同的焊接位置（即，平坦，水平，垂直向上和垂直向下）上进行了焊接实验。然后，评估了激光接头的几何形状，内部缺陷，机械性能和熔池动力学。结果表明，在使用高热量输入参数时，焊接位置对激光焊接质量有明显影响。扁平焊缝的顶面和垂直向下焊缝的根部表面均略微凹陷。而且，水平焊缝和垂直向下焊缝具有严重的由小孔引起的气孔缺陷，这导致相对较差的机械性能。分析表明，不同焊接位置的锁孔稳定性不同。在水平和垂直向下的位置很容易产生锁孔引起的孔隙。此外，固体金属块逸出气泡的路径，从而导致这些焊接位置的气孔更加严重。但是，当使用低热量输入参数时，焊接位置对激光焊接质量的影响较小，这是因为熔融金属较少，这使得钥匙孔在不同的焊接位置上更加稳定。