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Mary Bevan
Director, Corporate Communications

Making Friction Stir Welding Portable for Navy Ships

The Alpha circle welder demonstrated the concept of portable friction stir welding. The weld head shown here was driven by electric motors through flexible drive shafts.

Johnstown, PA November 01, 2017

The Office of Naval Research (ONR), under the Future Naval Capability program, has funded CTC to lead a team to develop a portable friction stir welding system for repairing cracks in sensitized aluminum on Navy ships.

Friction stir welding is an ideal technology for welding aluminum and is particularly well-suited for repairing cracks in 5xxx aluminum alloys. However, friction stir welding generates large forces, and the large, fixed machines are unsuited to perform repairs onboard ships.

The project team, comprised of CTC; the Naval Surface Warfare Center, Carderock Division (NSWCCD); and the University of South Carolina; first examined the process through tooling and parameter experimentation.

CTC fabricated an initial concept demonstrator, or Alpha circle weld unit. The Alpha unit performed a series of increasingly challenging welds, including inserts of new material in sensitized plate. After demonstration for ONR and Navy technical subject matter experts, the Alpha unit was modified to perform straight line welds.

CTC then designed and built the Beta unit, which performs oblong welds more suited to repairing long cracks.

The project has been hugely successful in developing a process and system that meets or exceeds Navy requirements. This tool has potential far beyond repair of cracks on CG 47 ships. Portable friction stir welding can bring the benefits of friction stir welding to any large aluminum structure for repair or new construction. This opens potential for application for both construction and repair in ship, trucking, and rail vehicles, or any other large aluminum structure. CTC has filed a provisional patent for this technology solution.