NORFOLK NAVAL SHIPYARD, Portsmouth, Va. —
Norfolk Naval Shipyard (NNSY) had a momentous win in innovation recently, developing and completing the first organic cold spray repair of the U.S. naval shipyards.
USS George H.W. Bush (CVN 77) had a repair opportunity arise in March 2020 after the discovery of damage to a water pump motor shaft. With the shipyard working to balance the mission while fighting the spread of COVID-19, a repair plan began to develop.
The solution: utilize the innovative repair process called cold spray. Cold spray is an additive repair process where the expansion of a compressed and heated gas is used to accelerate metal powder to sufficient velocity to cause the powder to deform and create a mechanical bond upon impact with a base material. The cold spray process occurs at significantly lower temperatures than traditional repair methods such as welding and thermal spray.
In Jan. 2019, America’s Shipyard began the process to retrofit the existing thermal spray booth in Bldg. 163 to support cold spray operations. As the NNSY Cold Spray team neared the final stages of the booth retrofit and towards attempting its first organic cold spray repair, the Bush component was identified and fit the criteria to be cold spray repaired.
“In order to execute this repair with cold spray, we had to utilize the recently published Uniform Industrial Process Instruction (UIPI) for cold spray and prove through a battery of required tests that cold spray would be a valid repair for the specific component,” said Code 265 Submarine Mechanical/Piping Branch Head Daniel Stanley, NNSY Transformation Manager for Cold Spray. “With the cold spray repair plan developed and tests identified, we manufactured and performed the application of cold spray on the necessary test coupons and mockup to support analysis by the Mid-Atlantic Regional Test Laboratory (Code 134). With the necessary testing passing Code 134 analysis and proving cold spray was a viable repair, we then pre-machined the component to support application of cold spray. With the part prepped and mounted within the cold spray booth, NNSY Mechanical Group Code 930 and Code 265 applied the cold spray and subsequently Code 930 did post machining on the part to return it to its final dimension.”
As this was the first cold spray repair performed at the shipyard, there was some initial hesitation to perform this process on the component. Stanley explained that the Bush project was initially hesitant to accept the risk of utilizing a technology which had never before been completed organically at NNSY taking into consideration their overall tight project schedule.
“With the first time execution of this process, as expected, we had encountered a number of situations we had not previously envisioned and gained many lessons learned,” said Stanley. “Even though the UIPI for cold spray was approved by both the shipyard and NAVSEA, this was the first time it was tested/executed in a shipyard environment. As issues arose, the NNSY team was able to leverage relationships with the cold spray team at Puget Sound Naval Shipyard (PSNSY) and Penn State Applied Research Laboratory (PSU ARL) to overcome the barriers encountered and provide ways to better improve our processes for the future.”
Another unexpected challenge was the safety precautions being put in place to combat COVID-19. “It was when we sent the cold spray repair coupons to the Code 134 lab for testing that the first high risk guidance was established at the shipyard,” said Stanley. “This greatly reduced the ability of the lab to complete testing as well as the number of production resources capable of doing the pre-machining for the component, cold spray repair itself, and the post-machining.”
In those times of uncertainty, Stanley and his team sought answers for how to perform the work safely and ensure the mission was upheld. “With the lab aspect complete, the team was able to obtain some assistance from Code 200 and Code 930, providing the necessary personnel to be put in place to support the pre/post-machining of the component. Meanwhile, Code 265 assisted Code 930 with execution of the cold spray application of the component,” said Stanley. Final machining of the component took place Apr. 1. The component is currently being assembled for shipboard use.
“Despite a significant decrease of personnel reporting to work and in the middle of the shipyard ramping up our fight against COVID-19, innovation forged ahead,” said Code 200 Engineering Planning Manager Michael Zydron. “Our shipyard family was able to come together to plan and complete this historic repair – even in the midst of a pandemic. Our team is a great example of excellence – maximizing the mission while minimizing the spread. Thank you to everyone involved!”
“It was a true teamwork experience working with the limited resources at hand,” added Stanley. “This is a huge win for the shipyard and the Cold Spray Community. The repair NNSY performed allowed the team to evaluate its facilities and identify improvements needed for future repairs. For the cold spray community, this repair is a major accomplishment as it shows that our efforts to implement cold spray within NAVSEA and the Department of Defense (DOD) are being successful.”
Stanley continued, “Having a cold spray facility in place at NNSY allows other shipyards and DOD facilities to establish a roadmap in respect to developing their own cold spray capabilities. In contrast to other technologies, cold spray’s primary challenges have been the facilities to support the operation. A running facility at NNSY also gives a conduit for organizations such as Penn State Applied Research Laboratory (ARL) or the Army Research Lab to transition some of their technology from the lab into a real world application.”
Stanley explained that this is only the beginning for cold spray being utilized directly at America’s Shipyard. “The cold spray team at NNSY has spent the last year renovating, upgrading and designing the facilities that are capable of supporting the operation of cold spray, driven mostly by the premise of a technology that would directly result in better repairs,” he said. “In respect to the shipyard, it has required a high-level of support both with funding and assistance in overcoming obstacles to get the facilities where they are today. As a result, we have nitrogen generation capabilities, two large rooms to perform cold spray operations, two robotic arms, a large array of workstations to handle a variety of components, and an exterior work cell with onsite machining capabilities.”
He continued, “In addition to this repair, NNSY recently completed a large cold spray repair for a seawater component from the USS San Francisco (SSN 711) project in support of its undocking. Cold Spray was VADM Thomas Moore’s (Commander, NAVSEA) number one priority for innovation in 2019 and we aim to continue to push the boundaries of how we could use this technology.”