Multiaxial Creep Rupture and Damage Evaluation for 2.25Cr-1Mo Forged Steel
Masayoshi FUJIMOTO, Masao SAKANE, Shingo DATE and Hiroaki YOSHIDA
Abstract:This paper studies the effect of stress biaxiality on creep rupture time and void growth for 2.25Cr-1Mo steel at 823K. Biaxial tension creep tests were carried out using 2.25Cr-1Mo cruciform specimens, and rupture times under biaxial stress states were experimentally obtained. Void growth in biaxial creep stages was observed by intermitting creep testing. The biaxial creep rupture times were slightly longer than the uniaxial creep rupture times in the correlation with Mises equivalent stress. Void nucleated earlier in biaxial stress states than in uniaxial stress states. Void number density and A-parameter were detected in the rupture life ratio less than 0.5 in biaxial stress states, whereas those were not detected before the life ratio of 0.7 in uniaxial stress state. The relationship between the void nucleation and rupture time in biaxial stress states was discussed based on the fracture mode. Key Words:Creep, Multiaxial stress, Damage evaluation, Void growth, High temperature