Optimization of welding parameters in the friction stir welding process

Wednesday, June 4, 2008 - 11:05 AM

Optimization of welding parameters in the friction stir welding process

R. Louro, H. Gouveia, P. Brioso, Instituto de Soldadura e Qualidade, Porto Salvo, Portugal; A. Loureiro, D. Rodrigues, University of Coimbra, Coimbra, Portugal

The process parameters are an important part of the FSW process, since they have an overbearing importance in both the quality of the welds and the process productivity. However the influence of the individual process parameters has not, so far, been reasonably established. There has been some research into this area, however these have been limited either to a single parameter or to very restricted welding conditions.

The aim of the work depicted in this paper is to conduct a large scale study, encompassing a significant variety of welding conditions, intended to determine the influence of all individual welding parameters. It is expected that by properly establishing them this would enable the development of several experimental methods for the industrial optimization of the FSW process, thus contributing to the wider use of this technology.

These objectives were attained by conducting a large series of welding tests under various welding conditions. More specifically, two different base materials, AA5083-H111 and AA6082-T651, and several base material thicknesses ranging from 3mm to 8mm. These welding conditions were selected in order to encompass the vast majority of the industrial welding needs.

The welding tests were conducted by varying the process parameters: welding speed, rotating speed, vertical force and pitch angle. The effect of the welding tool dimensions was also assessed by varying the pin diameter and the shoulder diameter. The welding tool possessed a classic geometry: cylindrical threaded pin and smooth concave shoulder. The Taguchi method was used as a mean to reduce the number of welding tests to a manageable number.

The results of this research led to a greater insight into the influence of the welding parameters in the welding quality and the process productivity and can have a significant influence in the future industrial optimization of the FSW process.

Summary: The research depicted in this paper in intended to develop industrial optimization methods for friction stir welding parameters. Comprehensive welding tests were carried out accounting for variations in welding parameters, tool dimensions and welding conditions. The influence of each parameter in the overall weld quality and productivity was ascertained.