Modeling of residual stress mitigation in austenitic stainless steel pipe girth weldment
Abstract
This study provides numerical procedures to model 40-cm-diameter, schedule 40, Type 304L stainless steel pipe girth welding and a newly proposed post-weld treatment. The treatment can be used to accomplish the goal of imparting compressive residual stresses at the inner surface of a pipe girth weldment to prevent/retard the intergranular stress corrosion cracking (IGSCC) of the piping system in nuclear reactors. This new post-weld treatment for mitigating residual stresses is cooling stress improvement (CSI). The concept of CSI is to establish and maintain a certain temperature gradient across the pipe wall thickness to change the final stress state. Thus, this process involves sub-zero low temperature cooling of the inner pipe surface of a completed girth weldment, while simultaneously keeping the outer pipe surface at a slightly elevated temperature with the help of a certain heating method. Analyses to obtain quantitative results on pipe girth welding and CSI by using a thermo-elastic-plastic finite element model are described in this paper. Results demonstrate the potential effectiveness of CSI for introducing compressive residual stresses to prevent/retard IGSCC. Because of the symmetric nature of CSI, it shows great potential for industrial application.
- Publication:
-
Presented at the American Welding Society International Conference on Modeling and Control of Joining Processes
- Pub Date:
- 1994
- Bibcode:
- 1994aws..conf....8L
- Keywords:
-
- Austenite;
- Intergranular Corrosion;
- Mathematical Models;
- Nuclear Reactors;
- Pipes (Tubes);
- Residual Stress;
- Stainless Steels;
- Stress Corrosion Cracking;
- Welded Joints;
- Welding;
- Compressibility;
- Cooling;
- Temperature Gradients;
- Structural Mechanics