Performance of an emergency cold weld repair on a 2.25Cr-1Mo longitudinally seam-welded pressure vessel.

Abstract

This is an overview of a current three-year project for the Cooperative Research Centre for Welded Structures entitled “Integrity of High Energy Piping”. The results of a performance evaluation conducted on an emergency cold weld (controlled deposition temperbead, TB) repair applied to a 2.25Cr-1Mo steel header using the manual metal arc welding (MMAW) process are described. With repair rather than replace being a far more viable option, welding is increasingly used for performing repairs, replacements, retrofits and modifications to elevated temperature plants. However, with the considerable cost and time involved with performing conventional post weld heat-treatment (PWHT) repairs, in today’s economic environment utility owners are increasingly forced to turn toward other alternatives, such as cold weld repairs. These require no PWHT and rely on a controlled deposition process – precise weld bead placement and heat inputs etc to achieve tempering of the HAZ. However, much of the research conducted on these repair techniques has used accelerated high temperature creep testing to demonstrate their integrity. How well this reflects their real-life performance is unknown. Therefore this study provides an opportunity to evaluate the effects of service exposure on the performance of an emergency cold weld repair. © 2003, The Institute of Materials Engineering Australasia Ltd