Heat generation during friction stir welding process

TLDR: Friction stir welding (FSW) is a promising welding technology from the same moment of its existence because of its easy use, low energy costs, being ecology friendly process and with no need for filler metal.

Abstract: Friction stir welding - FSW was a promising welding technology from the same moment of its existence because of its easy use, low energy costs, being ecology friendly process and with no need for filler metal. FSW works in the solid state of weld metals and basic goals of the process are to generate thermal energy by friction on contact of FSW tool and welding pieces, which will soften weld pieces and stir it with solid metal into weld. FSW process has five main phases: plunging into weld pieces, dwelling, moving along joint line for the weld creation, final dwelling and pulling out of the welding tool from the weld. Generated heat is in proportion with large number of parameters, but most significant are contact pressure between tool - weld pieces and speed. Significant thermal energy is generated during FSW and there is mathematical model which describe these stages but still there are several inaccuracies of the model that give some differences between theoretical and experimentally determined amount of heat.