Study on Creep Properties for TIG Welded Joints of CLAM Steel

摘要

The reduced activation ferritic/martensitic steel will withstand long-term high-temperature loading during the application in fusion reactors. In this work, the investigation of creep properties of China low activation martensitic (CLAM) TIG welded joints has been carried out at 823 K and with the applied stresses ranging from 180 to 260 MPa. The creep curve has been studied and plotted and the mathematical model has been constructed to analyze the creep mechanism. According to the results, the TIG welding joints of CLAM exhibited the typical three-stage creep curves, and at the constant temperature, the steady creep rate increased and the rupture time decreased with the increase of stress. The stress exponent n obtained from creep equation was higher than the typical values about 3-5, and activation energy Q was about 436 kJ/mol K, also higher than the self-diffusion energy of Fe (300 kJ/mol K), indicating the dislocation creep deformation mechanism, which is further proved by the microcosmic TEM images.