Effect of Pre-strain on the Creep Strength of Ni-Based Alloys for A-USC Boilers

摘要

In order to clarify the effects of cold work on the creep rupture strengths of Ni-based alloy, the relationship between the pre-strain and the creep rupture strengths of Alloy617, Alloy263, and Ally740H was investigated. The creep rupture strength of Alloy617 increased as the pre-strain increased. The creep rupture strength of Alloy263 was roughly constant, independent of pre-strain. Meanwhile, the creep rupture strength of Alloy740H was constant with a pre-strain up to 5 %, and deceased to about one third of the initial value with a pre-strain of 7.5 % or larger. From the results of microstructure observation, the relationship between the amount of carbide in grain boundaries and the pre-strain, coordinates well with the relationship between the change in creep rupture strength and the pre-strain.