Damage analysis and life prediction of a main steam pipeline at elevated temperature based on creep damage mechanics

Main steam pipelines are important components of power plants and chemical plants, which operated at elevated temperature and high pressure for the long term. Creep is a potential mechanism of failure of these pipelines. In this paper, the modified Karchanov-Rabotnov creep damage constitutive equation has been incorporated into finite element program ABAQUS through its user subroutine to predict the creep damage and service life of a serviced steam pipeline made of 10CrMo910 heat resistance steel. Creep tests and short-term tensile tests at serviced temperature of 540°C were carried out to get the material constants in creep damage constitutive equation, which are necessary in the mentioned creep damage and life prediction. Based on these, the analysis on stress and damage of a main steam pipeline serviced for 150,000 hrs was carried out. Stress and damage distribution and maximum damage location of the pipeline were obtained. The damage distribution and maximum damage location of the pipelines were obtained. Furthermore, the local creep damage analysis of a T-type joint serviced for 150,000 hrs was also carried out because T-type joint used in the main steam pipeline is one of weakness in the piping system. According to the results obtained above, the life evaluation of the pipeline and the T-type joint were performed.