LOW-CYCLE FATIGUE-STRENGTH AND SURFACE-LA YER - PROPERTIES ACHIEVED BY TURNING OF SUPERALLOYS

It is well known that the surface layer after machining has a signific ant influence on the LCF-strenght. The common practice for a high degr ee of the LCF-strength provided by the material itself is the requirem ent to produce small surface roughness and small changes in the surfac e layer by machining. In this paper it is described that a high depth of deformation by machining of Nickel-base-alloys can increase the LCF -strength remarkably. The results indicate as well that post machining shot peening and surface finishing for smooth surfaces have to be rev iewed with respect to their benefit.