System for using high rotary speed for minimizing the load during friction stir welding

A method for performing friction stir spot joining (FSSJ) of metal workplaces, said method comprising the steps of:

• 1) providing a FSSJ tool comprised of a shank, a shoulder and a pin, wherein the shoulder and the pin have features extending towards or extruding from a FSSJ tool profile;
• 2) rotating the FSSJ tool at a rate of speed that is greater than 4000 revolutions per minute (RPM);
• and
• 3) plunging the FSSJ tool into and then removing the FSSJ tool from at least two metal workpieces, resulting in a spot weld of the at least two metal workpieces.

A method for performing friction stir spot joining (FSSJ) of metal workpieces, said method comprising the steps of:

• 1) providing a FSSJ tool comprised of a shank, a shoulder and a pin, wherein the shoulder and the pin have features extending towards or extruding from a FSSJ tool profile;
• 2) providing a means for heating the FSSJ tool to thereby more rapidly heat at least a portion of at least two metal workpieces that come into contact with the FSSJ tool, thereby increasing a rate of flow of the at least two metal workpieces around the FSSJ tool;
• and
• 4) plunging the FSSJ tool into and then removing the FSSJ tool from the at least two metal workpieces, resulting in a spot weld of the at least two metal workpieces.