Premature creep failure in strength enhanced high Cr ferritic steels caused by static recovery of tempered martensite lath structures

The apparent activation energy for rupture life sometimes changes from a high value of short-term creep region “H” to a low value of long-term creep region “L”. This change results in overestimation of rupture life during long-term creep. This is called “premature creep failure”. Premature creep failure has been studied by the evaluation of microstructures of three kinds of Gr. 122 type steels and by paying attention to subgrains recovery of...