Study on the mechanism of de-embrittlement based on the theory of grain boundary segregation for 2.25Cr-lMo steel

摘要

The mechanism of embrittlement and de-embrittlement for 2.25Cr-l Mo steel was studied based on the theory of grain boundary segregation, and the idea of critical temperature of embrittlement for embrittled material was proposed according to the iso-segregation curve in this paper. There is one critical embrittlement temperature corresponding to each degree of embrittlement. When further heat treating temperature is higher than critical temperature, it is a de-embrittlement process. Otherwise, it is an embrittlement process. The model of segregation that element P segregates to intragranular from grain boundary in the de-embrittlement process was deduced based on the theory of atom diffusion. The de-embrittled test and Auger electron spectroscopy analysis were conducted for the matrix of hydro-genation reactor served for 12 years, and the theoretical calculation is consistent with the experimental results, which indicates that the further embrittlement or de-embrittlement mechanism can be explained both qualitatively and quantitatively with combination of the theory of iso-segregation curve and the de-embrittled model derived.