Abstract
This study discusses multiaxial low cycle fatigue life of Mod. 9Cr-1Mo steel under proportional and non-proportional loadings at room and high temperatures. Components and structures like pressure vessels and high temperature exchangers undergo multiaxial low cycle fatigue damage. For Mod. 9Cr-1Mo steel, a few studies on multiaxial fatigue has been performed, so examination of deformation and life behavior under multiaxial fatigue should be needed. In this study, strain controlled multiaxial low cycle fatigue tests under a push-pull, a reversed torsion and circle straining tests at room temperature and 823K were carried out using a hollow cylinder specimen of Mod. 9Cr-1Mo steel. Decrease in failure lives under non-proportional loading was remarkable. Failure life estimation and deformation and failure behaviors were discussed.
