D.H. Lammlein PhD Dissertation - Vanderbilt University

CHAPTER V
FRICTION STIR WELDING OF SMALL DIAMETER PIPE: AN EXPERIMENTAL
AND NUMERICAL PROOF OF CONCEPT FOR AUTOMATION AND
MANUFACTURING
D.H. Lammlein, B. T. Gibson, D. R. DeLapp, C. Cox, A. M. Strauss, G. E. Cook.
Friction Stir Welding of Small Diameter Pipe: An Experimental and Numerical Proof of
Concept for Automation and Manufacturing. Proceedings of the Institution of
Mechanical Engineers, Part B: Journal of Engineering Manufacture, Submitted July 15,
2010.
Abstract
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 aluminum 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 configuration geometrically from a butted plate
configuration and presents unique challenges. This work confronts these challenges
using experimental and numerical methods. A FSW process method producing
acceptable pipe joints is demonstrated.
Introduction
Friction stir welding (FSW) is an effective and consistent materials joining
technology which produces high strength and high integrity joints, particularly in
aluminum alloys (Thomas, 1991). FSW is also attractive because it is a solid-state
process, with temperatures not exceeding the melting point of the work material. Its use
is limited primarily by the combined expense of the FSW machine itself and the lack of
an operating knowledge base. However, superb joint quality and low continuing
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