Advanced manufacturing process for high-performance engine parts
NSHIPping of powder has the potential to revolutionise the production of complex high-performance aerospace parts, enabling improved buy-to-fly ratios that can be high for many flying components because of complex geometries. This process applies elevated temperatures and pressures within an autoclave to produce dense complex-shaped components from different powder materials. The result is that finished near net shape components have superior mechanical properties compared to those manufactured using traditional production methods. The EU-funded project NESMONIC (Net shape manufacture of Ni superalloy engine casing) successfully exploited this technology for the production of an engine casing from IN718, reporting an 80 % reduction in aerospace material consumption and the elimination of swarf disposal and recycling costs. The manufacturing process also allowed a 75 % reduction in energy consumption as a result of reducing energy-intensive machining operations. Scientists addressed a number of challenges associated with the implementation of this technology on engine parts. These included the difficulty in HIPping the nickel (Ni) superalloy powder, the high cost of sacrificial tooling, diffused surface layer on components because of the interaction with the tool material and, finally, the lack of credible performance information for IN718 parts produced using the NSHIP process. The team conducted several trials to determine the best powder and HIPping conditions to use to produce parts with the desired microstructure and properties. Novel low-cost tooling methods were developed and surface engineering techniques to eliminate tool-component interaction were also explored. NESMONIC used a computation model of IN718 powder consolidation to calculate the correct tool geometry to enable right-first-time net shape parts to be produced. The NSHIP process offers the opportunity to manufacture complex components under the high pressure and temperature critical to achieve the required fuel burn reductions in large civil aero engines. Use of hotter engine cycles enabled by high-performance Ni alloys decreases engine emissions, helping the aerospace industry achieve the tough Advisory Council for Aeronautics Research in Europe (ACARE) targets, such as a 50 % reduction in carbon dioxide emissions by 2020.
Keywords
Advanced manufacturing, net shape hot isostatic pressing, aero engine, NESMONIC, IN718
