Comparison of Electrically-Assisted and Conventional Friction Stir Welding Processes by Feed Force and Torque

Abstract

The process of friction stir welding involves high tool forces and requires robust machinery; the forces involved make tool wear a predominant problem. As a result, many alternatives have been proposed in decreasing tool forces such as laser assisted friction stir welding and ultra-sound assisted friction stir welding. However, these alternatives are not commercially successful on a large scale due to scalability and capital/maintenance costs. In an attempt to reduce forces in a cost-feasible manner, electrically-assisted friction stir welding (EAFSW) is studied in this work. EAFSW is a result of applying the concept of electrically-assisted manufacturing (i.e., passing high direct electrical current through a workpiece during processing) to the conventional friction stir welding process. The concept of EAFSW is a relatively new adaptation of conventional frictional stir welding, which is well established. The expected benefits are reduction in the feed force and torque, which allow for improved processing productivity as well as the possibility for deeper penetration of the weld.

Electrically assisted friction stir welding for joining Al 6061 to TRIP 780 steel

“…Similar study was also conducted by Potluri et al (2013), where an average reduction of 58% of feed force was observed with electric current passing through the Al6061 weld specimens.…”

A review of electrically-assisted manufacturing

“…The Z-axis force of EAFSW is decreased more significantly than that of the conventional process, 89 and the weld speed and power consumption are improved. 90 Recently, Potluri et al 91 reported that this process also eliminated the limited penetration depth and reduced tool wear in the plunge and weld (Fig. 15).…”

Numerical optimisation of laser assisted friction stir welding of structural steel

“…It was found that the tool torque was reduced by about 10 percent with preheating and the use of acoustic softening of the material [11]. Research by Potluri et al [1] demonstrated the feasibility of using electric heating in the friction stir welding process on Aluminium. A large amount of current was passed through the workpiece to generate a temperature rise along with the direct material softening [1].…”

“…Research by Potluri et al [1] demonstrated the feasibility of using electric heating in the friction stir welding process on Aluminium. A large amount of current was passed through the workpiece to generate a temperature rise along with the direct material softening [1]. The traverse force was decreased up to 59% on average as compared to the conventional friction stir welding process [1].…”