Development of Fatigue Crack Growth Rate Equations for Ni-Base Alloys

Abstract

Nickel alloys—specifically Alloys 600 and 690 and their associated weld metals, Alloys 82/182 and 52/152/variants—are used for numerous components in nuclear power plants. Fatigue is a degradation mechanism that affects these materials, so fatigue crack growth must be considered in flaw assessments and evaluations per ASME Boiler and Pressure Vessel Code, Section XI. Currently, fatigue crack growth rate (FCGR) equations for Alloy 600 in air and water environments are provided in Section XI. There is a need for corresponding equations that describe the FCGR behavior of Alloy 690 wrought material and the associated weld metals. The present work reevaluates the Alloy 600 FCGR equations currently included in Section XI using a broader database of laboratory data and develops new FCGR equations for Alloys 690, 82/182, and 52/152/variants in air, BWR, and PWR environments using publicly available laboratory data.