Advanced tooling demonstration for friction stir welding (FSW) of heat resistant materials

Tuesday, September 14, 2021: 1:20 PM
222 (America's Center)
Dr. Judy Schneider, Ph.D , University of Alabama at Huntsville, Huntsville, AL
Mr. Todd Leonhardt , Rhenium Alloys Inc., North Ridgeville, OH
Although friction stir welding process (FSW) was invented in 1991 to join aluminum alloys, its advancements in the tool material and designs have been lagging to realize the benefits in the joining of high strength and heat resistant alloys such as steel, titanium and nickel based super alloys. The main limitation in expanding the solid state process into joining of these materials has been in finding a tool material that can reliability retain its structural integrity under the FSW loads at temperatures in excess of 1000ºC. These conditions can cause deformation, excessive wear, and catastrophic fracture during operation which ultimately reduce the robustness and reliability of the joints produced. While the FSW process has been demonstrated in joining the higher strength and higher melting temperature materials such as titanium and Inconel, tool erosion, wear and fracture ultimately limited the length of the FSWs that could be achieved. Thus, this technology cannot advance without viable tooling that is robust and can be economically produced. Recently a low cost W-25%Re-4%HfC tool has been fabricated and demonstrated to realize the reliable joining of steels and titanium alloys using the FSW process.