Evaluation of Size Effect due to Oxidation Thinning in Ultra-Miniature Creep Test on Modified 9Cr-1Mo Steel

Abstract

In this study, conducting an ultra-miniature creep (UMC) test in an argon gas environment on a modified 9Cr-1Mo steel, the size effect on creep-rupture life was discussed from the viewpoint of oxidation thinning. As a result, the maximum thickness of the oxide layer produced on ruptured UMC specimens was found to be less than 2μm. Also, calculating a life reduction rate due to the oxidation, the rate was less than 10 % at the thickness of 2μm. Therefore, it could be indicated that the oxidation had little influence on the rupture time of the UMC specimen at least within several thousand hours.