Numerical simulation of temperature field in 9% Cr steel thick-wall pipe in local PWHT

A FE program which could adjust heat input automatically according to the temperature at the controlling point was developed based on the heat input tracking method. The temperature distributions of 9% Cr steel pipe in local post weld heat treatment (PWHT) was simulated by using this program. The simulation results were in good agreement with the experimental results. The temperature field distributed as a parabola at the axial direction. There existed approximate linear relationship between metal temperature and radial distance. The temperature variations between the outer wall and the inner wall was about 17~18 ℃ within the distance of two times wall thickness to the weld center. The calculated soak band width according to the local PWHT parameters recommend by current domestic standard was wide enough to meet the requirements of heat treatment. Equivalence point on the outer wall which had the same temperature as the weld center in inner wall was obtained in order to monitor the temperature variation in inner wall during PWHT.