Shot peening is used to introduce the desired compressive residual stresses but typically increases the surface roughness.
One applied solution is shot peening of the aerofoils followed by vibropolishing.
To achieve these partly competitive requirements more then one surface modification process are needed today. Todays typical requirements for HPC aerofoils are a low surface roughness of Ra ≤ 0,25 μ m and elliptical leading edges for performance reasons as well as appropriate high cycle fatigue (HCF) life. Decreasing accessibility combined with increasing demands for aerodynamic and product life cycle performance brings current mechanical surface treatment technologies to their limits. The demand for high compression ratios, small compressor sizes and material saving design causes the need of reducing component dimensions as well as raising the number of blades per stage. These loads are effective against the blades which thicknesses are progressively decreasing caused by aerodynamic design and lightweight construction. 1) have to resist heavy loads caused by a combination of cyclic mechanical and thermal loads as a result of high rotational speeds, instable aerodynamic forces, and high compression ratios. This design change enabled a significant weight reduction combined with a increase of engine performance. During the last 15 years the design of high pressure compressor (HPC) drums changed from conventional bladed bolded drums to multistage electron beam welded blade integrated disk (blisk) rotors. industry sets standards to performance effective design, lightweight construction and cost efficient manufacturing.
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