ABSTRACT
Friction stir welding (FSW) was developed by The Welding Institute (TWI) in the United Kingdom in the early 1990s [1]. Over the past two decades, a number of developments and modifications have been made to FSW and a similar sister process, friction stir processing (FSP) [2,3]. In general, FSW involves rotating a welding tool (comprised of a shank, shoulder, and pin) at a prescribed speed and tilt and plunging the weld tool into the workpiece material until the tool intimately contacts the workpiece surface and generates friction. The friction produces intense heat that bonds the workpiece materials as the weld tool traverses the joint line. Heat generated during the
CONTENTS
Introduction ......................................................................................................... 167 Nuclear Fuel Fabrication .................................................................................... 169
Research and Test Reactors ........................................................................... 169 Fabrication of Monolithic Fuel Plates with FSW ....................................... 171 Future Work .................................................................................................... 175
Reactor Pressure Vessel Repair ......................................................................... 178 Current Light Water Reactor Structural Components .............................. 178 Potential of FSW for Reactor Vessel Repair ................................................ 180 Future Work .................................................................................................... 182
Fabrication of Canisters for Spent Nuclear Fuel............................................. 183 Copper Canisters for Spent Nuclear Fuel ................................................... 184 Initial Studies Employing FSW .................................................................... 185 Future Work .................................................................................................... 186
Nondestructive Evaluation of FSW Joints ....................................................... 187 Conclusions .......................................................................................................... 188 Acknowledgments .............................................................................................. 188 U.S. Department of Energy Disclaimer ............................................................ 189 References ............................................................................................................. 189
process due to deformation and relative motion of material around the tool pin sufficiently softens the material without reaching the solidus temperature. The leading face of the tool pin forces the plasticized material to the back of the tool while concurrently applying a substantial forging force to consolidate the weld metal, resulting in a high-integrity joint. A schematic of the FSW process is shown in Figure 7.1 [4].
