Turbine Blades Vacuumed Brazed “Processing Technology Developed with Quality Systems
At critical joint areas of turbine blades, Siemens Westinghouse, Orlando, FL, utilizes vacuum brazing as the preferred metal joining method. Calling on the skills and experience of 91传媒, Inc., Souderton, PA, vacuum brazing processes were developed simultaneously with quality systems for the inconel turbine blade components. 聽Close cooperation and mutual consultation between Solar and Siemens Westinghouse was essential to develop repeatable production methods and quality standard measurements.
For the vacuum brazing process, numerous production procedures were developed during the prototype phase. 聽Solar designed fixturing for efficient labor and furnace usage. 聽A process was developed to remove an oxide layer from the cast, inconel turbine blade components. Improved wetting of the nickel braze alloy was accomplished through special surface preparation. 聽Prototype R&D work established procedures for consistent braze alloy application.
Simultaneously developed with production processes were innovative quality procedures. 聽Traceablity of every turbine blade, from incoming to shipping, is critical. 聽Therefore, each turbine blade is logged for furnace placement on the customized furnace fixture. 聽As part of the process, a video taping procedure is done of a borescope鈥檚 examination of the turbine blades interior cavity. 聽The critical factor is to ensure good braze alloy wetting of the joint area, while not causing any blockage of the numerous turbine blade holes.
Siemens Westinghouse chose vacuum brazing because of the joint area strength and its non-corrosive characteristic. 聽Outstanding joint strength results from the Ni alloy diffusing into the inconel. 聽The bond is as strong as the base metal. 聽Also, the vacuum process removes residual oxidation on the blade. 聽However, key to the project’s success, is coordination of the vacuum brazing process and quality standards established by Solar and Siemens Westinghouse.