Johnstown, PA February 03, 2021

Under the Aluminum Sensitization Measurement and Control (ASMC) program, Concurrent Technologies Corporation (CTC) is implementing solutions that will reduce costs and improve readiness for U.S. Navy ships that utilize aluminum alloys for hulls and superstructure. Sensitized aluminum is particularly susceptible to stress corrosion cracking. CTC’s innovative repair techniques and technologies allow repairs to in-place cracked and damaged aluminum, saving the costly and time-consuming removal and replacement process.

A CTC team is recently back from a trip to BAE Systems in Norfolk, Virginia, where they repaired a section of aluminum on the USS Vicksburg (CG 69). They repaired a section of bulkhead that had a hole in it using a portable friction stir welder (PFSW) to weld an insert into sensitized aluminum. CTC also worked with a partner, ElectraWatch Inc., to treat the surrounding area with another CTC-developed technology, reverse sensitization*. Their work builds on prior activities at CTC involving PFSW, reverse sensitization, coatings, and other technologies. 

“This is an important development since this new strategy was not only used to demonstrate the effectiveness of these technologies, but also to actually repair a section of a working U.S. Navy ship,” said Rob Mason, CTC Principal Materials Scientist and ASMC Program Manager. “We saved the Navy about $250,000 in two days’ time. CTC’s Tim Freidhoff and Dan George did a phenomenal job, as did our ElectraWatch partners.”

The normal process to cover a hole in superstructure is to either remove the entire area of bulkhead and replace it with new aluminum material, or to install a temporary eight-layer fiberglass patch, which must be subsequently repaired during a Depot-level availability. The wholesale removal and replacement process costs between $300,000 to $500,000. By comparison, the successful PFSW / reverse sensitization repair cost only $22,000. This new repair approach is applicable on all Navy ships that use aluminum alloys, with specific focus on CG 47 (Ticonderoga class) cruisers. CTC is executing the ASMC Program through the Ingalls Shipbuilding CG 47 Class Planning Yard contract, which supports the modernization of CG 47 Class cruisers.

*Available from ElectraWatch, Inc.,

Read more about our friction stir welding capabilities.