Average creep rate model for prediction of stress relaxation

摘要

An estimation method is proposed to predict stress relaxation performance of structural materials.An average creep rate conversion model based on Schlottner-Seeley creep assessment procedure and creep damage equations has been developed by considering the relationship between two stages of stress relaxation corresponding to the first and second creep stages respectively.The macroscopical effect of these two kinds of creep rate on stress relaxation is investigated at various stresses.The integrated methodology for prediction of stress relaxation is established and compared with the experimental results.The uniaxial isothermal stress relaxation tests are conducted on lCrl0NiMoW2VNbN steel with the same temperature as the normal creep tests.Validation results indicate that the prediction by the developed model has a good consistence with the measured data and thus can be recommended in stress relaxation performance prediction of high temperature materials.