Simulations of Rectifications which are Needed in Dynamic Wire and Hot Wire GTAW of 304HCU Tubes of Reheaters and Superheaters using ANSYS 2021

Abstract

The aim of this project is to simulate the rectification that are needed in hot wire and dynamic wire gas tungsten arc welding of reheater and superheater tubes made of 304hcu ss using a simulation software like ansys 2021. The given grade of stainless steel is of 300 series with chromium and nickel austenitic stainless steel are non hardenable by heat treating and corrosion resistant. 304 hcu ss has a better microbiologically influenced corrosion resistance. The gas tungsten arc welding (gtaw) process: also known as tig welding, it is an electric arc welding process in which the fusion energy is produced by an electric arc burning between the workpiece and the tungsten electrode. It differs from other arc welding processes by the fact that the electrode is not consumed like other electric arc welding process. To prevent hot cracking, welding with a heat input below 2 kj/mm, using an interpass temperature below 150 °c, is recommended. To avoid stress corrosion cracking, contact with certain solutions, particularly those containing chlorides should be avoided. Extra care needs to be taken during plant shutdowns as chloride containing condensates can be formed leading to stress corrosion cracking. However, cracking requires the presence of high stresses and is therefore more likely to occur in thicker sections, t- joints, like header-tube connections, or joints with dissimilar metal thickness, where the higher restraints can lead to higher residual stresses after welding than in thin-walled superheater/reheater tubing with butt welds.