Friction stir welding: Process, automation, and control

Friction stir based welding and processing technologies - processes, parameters, microstructures and applications: A review

https://nottingham-repository.worktribe.com/preview/770243/Review%20of%20FSW%20of%20AMC_MD_2015.pdf

A review of friction stir welding of aluminium matrix composites

Joining by forming—A review on joint mechanisms, applications and future trends

Copper and aluminum materials are extensively used in different industries because of its great conductivities and corrosion resistant nature. It is important to join dissimilar materials such as c...

A Review on Dissimilar Friction Stir Welding of Copper to Aluminum: Process, Properties, and Variants

The need to join dissimilar materials such as aluminum and steel is prevalent in many industries. This paper investigates a new process called Friction Stir Extrusion (FSE) for joining aluminum and steel. The process uses Friction Stir Welding (FSW) to extrude aluminum into a premade concave groove cut into steel. FSE eliminates the concerns of intermetallic compounds and tool wear. This technique leads to a mechanically bound joint whose strength is determined by the mechanical bond between the steel and the extruded aluminum. Successful joints were created showing the FSE process has the potential for application to any combination of dissimilar materials.

Friction Stir Extrusion: A new process for joining dissimilar materials

Friction stir welding (FSW) is a powerful joining process which is limited by its range of application and processing rate. Here the range of application is extended to small-diameter butted pipe sections and high processing rates are applied for increased productivity in manufacturing. Full penetration friction stir welds are performed on butted sections of alumin- ium alloy 6061-T6 pipe. These pipe sections are relatively small in diameter (4.2 inches) and relatively thin walled (0.2 inches). The small radius of curvature distinguishes this weld config- uration geometrically from a butted plate configuration and presents unique challenges. This work confronts these challenges using experimental and numerical methods. An FSW process method producing acceptable pipe joints is demonstrated.

The friction stir welding of small-diameter pipe: an experimental and numerical proof of concept for automation and manufacturing

Sensing and closed-loop control are critical attributes of a robust 3D printing process, such as Directed Energy Deposition (DED), in which it is necessary to manage geometry, material properties, and residual stress and distortion. The present research demonstrates multiple modes of closed-loop melt pool size control in laser-wire based DED, a form of large-scale metal additive manufacturing. First, real-time closed-loop melt pool size control through laser power modulation was demonstrated for intralayer control of bead geometry. Aspects such as controller tuning, response time, interaction with primary process variables, and disturbance rejection are presented. Next, an interlayer trend in laser power during the printing of layered components was documented, which inspired the development of novel modes of control. A controller that modulates print speed and deposition rate on a per-layer basis was developed and demonstrated, enabling the control of either average melt pool size alone or average laser power in coordination with real-time melt pool size control. This work demonstrates that accumulated heat in components under construction can be exploited to maintain process stability as print speed and deposition rate are automatically increased under closed-loop control. This has major implications for overall production efficiency. Control modes are characterized in terms of their effect on local bead geometry, global part geometry, and interlayer effect on energy density, among other factors.

Melt pool size control through multiple closed-loop modalities in laser-wire directed energy deposition of Ti-6Al-4V

Friction stir welding (FSW) is the preferred joining method for metal-matrix composites (MMCs). As a solid-state process, it precludes formation of the intermetallic precipitates responsible for degradation of mechanical properties in fusion welds of MMCs. The major barrier to FSW of MMCs is the rapid and severe wear of the welding pin tool, a consequence of prolonged contact between the tool and the harder reinforcements which give the material its enhanced strength. This study evaluates the effectiveness of harder tool materials to combat wear in the FSW of MMCs. The tool materials considered are O1 steel, cemented carbide (WC-Co) of the micrograin and submicrograin varieties, and WC-Co coated with diamond. The challenges which accompany the application of harder tool materials and diamond coatings in FSW are also discussed. This study represents the first use of diamond-coated tools in FSW and the first comparative evaluation of tool materials for this application.

Brian T. Gibson

Papers

Friction stir welding: Process, automation, and control

Friction Stir Extrusion: A new process for joining dissimilar materials

The friction stir welding of small-diameter pipe: an experimental and numerical proof of concept for automation and manufacturing

Melt pool size control through multiple closed-loop modalities in laser-wire directed energy deposition of Ti-6Al-4V

A Comparative Evaluation of the Wear Resistance of Various Tool Materials in Friction Stir Welding of Metal Matrix Composites