Repairing turbines with a supersonic blast of metal particles

A highly anticipated capableness with the imaginable to repair hydroelectric dam turbines without the melting associated with accepted repair methods has made its mode to the Pacific Northwest National Laboratory (PNNL) for validation research.

The capability, called Cold Spray, is the newest summation to PNNL's suite of Solid Phase Processing, oregon SPP, tools.

SPP is simply a disruptive attack to metals manufacturing that tin beryllium better, cheaper, and greener than melt-based methods typically associated with metals manufacturing. It is poised to supply a distinctive competitory vantage to U.S. manufacturing.

A supersonic blast of metallic particles

Almost each authorities successful the U.S. uses hydropower for electricity. For example, 74 percent of Washington State's electricity comes from hydropower.

Over time, though, the unit of the h2o causes cavitation—typically pits and cracks—on the aboveground of the turbines. That amounts to precocious repair costs and mislaid gross for dam operators, who indispensable unopen down the turbines to repair them, typically utilizing arc welding.

The problem—the vigor from the welding melts and degrades the metal, causing the turbine to incur cavitation harm astatine an expanding rate.

Enter Cold Spray, which sprays tiny metallic particles onto the damaged country of the turbine astatine supersonic speeds, with nary melting involved. The particles interaction the aboveground hard capable to signifier a bond, producing materials and coatings with superior hardness, deterioration resistance, and corrosion resistance.

PNNL has taken receipt of a Cold Spray strategy developed by VRC Metal Systems, and it is considered that company's astir existent technology. The acold spray process tin marque turbine blades importantly much resistant to harm implicit arc welding repair approaches, according to laboratory investigating performed to American Society for Testing and Materials (ASTM) standards.

PNNL is present actively moving with hydropower collaborators toward an archetypal tract exertion of the exertion to validate the melodramatic improvements seen successful the ASTM testing.

"We person economic data that enabled america to reason that erstwhile Cold Spray exertion is established for hydro repairs, it volition importantly trim downtime and repair frequence owed to absorption to cavitation erosion," says PNNL mechanical technologist Chris Smith. "It besides gives dams the flexibility to clip needed repairs, for example, during times of drought."

The squad is besides looking into utilizing Cold Spray to make solutions for different parts of the vigor sector. For example, they person investigated repair and mitigation of corrosion harm successful atomic discarded retention canisters utilizing Cold Spray.

Beyond repair, Cold Spray tin besides beryllium utilized arsenic an additive manufacturing process. Because the Cold Spray metal particles bash not melt during the process, determination is the imaginable to make full caller alloy systems that are different incompatible successful melt-based processes.

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