Portable Metallography Applications Based on Replica Technology Demonstrated for Non-Destructive Tests of Large Gas Turbine Parts

摘要

Portable metallographic test procedures contribute significantly to assuring a company's large machine components' quality. Only by using this type of testing, it is possible to assess non-destructively, i.e. without sampling, the microstructure and identify deviations. Excluding portable microscopes with limited amplification, there are no microscopes to test large-sized components on-site in a non-destructive manner. The present paper demonstrates some variants of applications for this analysis using replica foils, with particular focus on the opportunities and limits of lateral resolution of structural details obtained by means of replica technology. The examples shown are derived from the production of large machines, in particular from manufacturing large industrial gas turbines. The widely differing temperatures in these turbo machines range from about -40 deg C to 1500 deg C and demand an appropriate material selection by the designing engineer. Consequently, the material spectrum of the showcases ranges from ductile iron to nickel- based superalloys.