Enhancement of tensile strength in GH4251 alloy joints via preheated electron beam welding

In this study, high-quality welding joints of GH4251 alloy were successfully achieved using a preheated electron beam welding process. Microscopic structural analysis of the weld zone revealed that preheating effectively mitigated the formation of solidification cracks. Room-temperature tensile testing demonstrated that, under a preheating condition of 800 °C, the tensile strength of the joints reached 1515 MPa — 96 % of the base metal strength. The fracture analysis indicated that the failure occurred in the weld zone, exhibiting numerous dimples on the fracture surface, which is characteristic of a typical ductile fracture.