Creep Damage Analysis Using the Gurson Model on Welded Joints of Mod. 9Cr-1Mo Steel

摘要

This paper proposes a new numerical method of the creep damage evaluation of a mod. 9Cr-1Mo steel welded joint. Its creep damage mechanisms are mainly the nucleation of creep voids, their growth and coalescence in a softened region of its heat affected zone. Then creep constitutive equations ahve been formulated using the Gurson Model as the creep potential. The damage parameter of this model is the void volume fraction that is easy to compare with measured damage values. The damaged area in a welded joint of this steel is usually smaller than its wall thickness. Then the locally coupled technique has been employed. The accuracy of this 0proposed method has been exmained by simulating uniaxial creep tests of round bar specimens of welded joints. Their lives have been predicted within a factor of two.