General Electric Company
Qualifying a cold working and polishing process

Abstract:

A method for determining sufficiency of compressive residual stresses in region below cold worked surface covered by a polished surface. Method includes obtaining surface height data along scanning passes over unpolished surface of the cold worked surface and the polished surface, determining region of surface height data with low and high points, and calculating step height by calculating difference between low and high points. Determining average height of the polished surface and peak height of the unpolished surface for the low and high points respectively. Cold worked surface may be peened surface. Confocal scanning microscope may be used for obtaining surface height data. Method may be used for qualifying a cold working or peening and polishing process for an airfoil which may include at least one feature from group consisting of camber, twist, curve away from the span, and lean away from the span.