Assessment of Damage Accumulation and Property Regeneration by Hot Isostatic Pressing and Heat Treatment of Laboratory-Tested and Service Exposed IN738LC

Abstract

Damage accumulation during creep testing of IN738LC has been quantitatively characterized. The effects of hot isostatic pressing (HIP) on specimens interrupted after various strains have been considered in relation to both the healing of damage and the subsequent mechanical performance. HIP shows little advantage over re-application of the conventional heat treatment in regenerating the creep performance. Examination of service retired rotor blades from an industrial gas turbine show little evidence of creep damage and considerable recovery of creep strength is obtained by heat treatment without pressure.