Nanoheater Underwater Robotic Welding for Marine Construction and Manufacturing

Underwater manufacturing and maintenance processes such as welding are accompanied by high occupational risks for welder-divers. This paper attempts to eliminate these hazards by introducing a 6-degree of freedom underwater welding robotic system to ignite nanoheater foils for metal joining, thusextending the use of these nanoheaters from soldering, brazing, and joining of components in microchip industry to underwater welding. Ni/Al reactive multilayers are utilized to perform aluminum sheet component joining. These commercially available nanoheaters release large amounts of heat when an exothermic reaction is initiated by an electrical ignition stimulus. Integrity of the welds performed by nanoheater underwater welding is ensured through introducing openings in the nanoheater foil, allowing for weld areas in a lap joint. The generated temperature field is simulated during such welding, establishing the Al sheet and nanoheater thickness, as well as the opening geometry conditions for reaching the melting temperature at the weld interface to generate successful and sound joints in the experiments.