Life improvement of aluminum alloy impeller for centrifugal compressor by modification of forging processes

摘要

The relationship was clarified between the mechanical properties and microstructure of a forged aluminum alloy used as the impeller for centrifugal compressors. New forging processes were developed to obtain a higher creep resistance material with longer lifetime under the same conditions. The three-dimensional forging process drastically reduced macro flaws in the impeller, and lowering the forging temperature diminished sub-boundaries and precipitation free zones along sub-boundaries.Consequently, the new forging process impeller has excellent creep ductility and high notch-creep rapture strength. Elasticplastic analysis confirmed that local high stress in the impeller could be redistributed quickly.