Formation of Sub Grains During Friction Stir Welding of Gas pipes

Appropriate selection of Friction Stir Welding parameters i.e. rotational speed, translational speed, and downward force as well as suit design of tool will contribute to formation of a strong weld due to equal amalgamation of welded materials in the steady state conditions. In this experimental study, two gas pipes were sufficiently welded on a predesigned fixture and results were concluded subsequently. Scanning electron microscopy (SEM) an optical microscopy (OM) were employed as metallurgical tests to evaluate the grain sizes and morphological characteristics in transmuted area (welding zone). The feedbacks from metallurgical tests revealed a equal distribution of subgrains over the welding area. Also, consequenses showed a range of grain sizes from micro to sub micro scale. Furthermore, hardness test as mechanical test showed more wear strength on the welding zone. Thus, current investigations indicate by selecting the suit parameters, friction stir welding will create substructures on the welding area of pipes.

کلیدواژه ها:

Friction stir welding ، Gas pipes ، Low carbon steel ، Sub grain