Development of ceramic backing for friction stir welding and processing

Usually, the workpiece is deformed during the friction stir welding, due to high applied loads. Consequently, fully and consolidated friction stir welded joints as well as tools life time can be affected promoting unscheduled manufacturing stops which favorites decreasing the welding productivity. Furthermore, the workforce is dislocated to not predicted maintenance steps. This work proposes the development of a special ceramic backing to joining and processing material using FSW technologies. Four ceramic deposits were tested over a steel plate, which allowed selecting those with less porosity and, thus, better strength. This backing allowed to obtain full penetration welds for duplex stainless steels, to resist high forces during engage for high strength low alloy steels and to obtain consolidated aluminum-steel dissimilar joints. For the last one, there was not adherence of the soft material in workpiece. In addition, the ceramic backing allowed confine the heat and plasticized metal, as well as developing established welding parameters.