PNNL

Abstract

Improved manufacturing processes improves the cost and quality of goods. Rotary friction welding (FW) is a fast, environmentally friendly, and reliable joining process for metals, but new applications are hindered by large development costs for each new alloy. Each alloy set has dierent welding characteristics, and therefore lessons learned from a single alloy are not always broadly applicable. In order to establish knowledge that is applicable across multiple alloys, a family of dierent superalloys were welded to discover process trends that were applicable beyond a single alloy set. High feedrates, high welding forces, and low temperatures all resulted in high strength welds across all alloy and geometry combinations. Tensile strengths greater than 95% of basemetal strength was recorded for most alloy systems. Some previous studies have suggested that high strength joints are associated with weld symmetry - an easily observable post-weld characteristic. In this study, weld symmetry did not correlate to weld strength across alloy systems. Some alloys' strongest welds occurred at maximum symmetry, whereas high asymmetry was associated with dierent alloys' maximum strength.