The manufacture of large, complex components for ultra-supercritical and oxy-combustion applications will be extremely costly for industry over the next few decades as many of these components will be manufactured from expensive, high strength, nickel-based alloys casting and forgings. The current feasibility study investigates the use of an alternative manufacturing method, powder metallurgy and hot isostatic processing (PM/HIP), to produce high quality, and potentially less expensive components for power generation applications. Benefits of the process include manufacture of components to near-net shapes, precise chemistry control, a homogeneous microstructure, increased material utilization, good weldability, and improved inspectability.In this study, a 780kg (1716 lb), 300mm (12-inch) diameter, 316L stainless steel valve body was manufactured using the PM/HIP process. The valve body was characterized using shear-wave ultrasonic examination techniques to evaluate both detection and sizing characteristics of the PM/HIP produced component. Additionally, one of the flanges from the valve body was also removed, sectioned, and tested mechanically and microstructurally to assess properties. Mechanical results produced at room and elevated temperature, 316°C (600℉), suggest the PM/HIP process is capable of producing superior properties to that of conventional cast or forged components in the time independent mechanical property regime. Based on these results, additional component manufacture and testing is planned to develop data packages to submit to the ASME Boiler & Pressure Vessel Code for various alloys during 2011/12.
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