Influencing factors of weldability of K465 precipitation strengthening nickel-based superalloy and its optimization methods

Objective The aim is to improve weldability of K465 precipitation strengthened nickel-basing superalloy. Methods By optimizing key welding parameters of tungsten inert-gas arc welding (TIG) including welding wire composition, welding current and bevel angle, combining with characterization techniques such as metallographic microscopy and scanning electron microscopy, this study analyzes influence of welding parameters and welding wire composition on crack initiation in welded joints. Results The results indicate that Al, Ti and Co elements in welding wire, as well as welding current and bevel angle, significantly affect quality of weld. To reduce the number of cracks, it is recommended to maintain a certain Al/Ti ratio in welding wire while increasing content of Co. Welding current should be kept below 40 A, and bevel angle should be controlled within the range of 60°～90°. Conclusion Through optimizing welding process and welding wire composition, tensile strength of weld joints achieves 86.8% of parent material at room temperature, and 79.2% at high temperatures.