The Development of Unified Residual Life Assessment Method for High Temperature Steam Piping Welding Joints for Boilers Using Low Cr Alloys

摘要

We developed the Unified Residual Life Assessment Method, which can use coarse HAZ, Coarse Weld Metal, Fine HAZ and Fine Weld Metal at Welding Joints. They are constructed by Damage Mechanism at Welding joints that links between Voids at last stage destruction. For example, 'M' parameter method developed before 3 years can use coarse HAZ and Coarse Weld Metal. This method actually has been using at a lot of service plants. New parameter Named 'L' parameter can use Fine HAZ, Fine Weld Metal . We can assess residual life highly accurately by a combination of them. We consider that they are combined we can have the highest accuracy "Factor of 1.5". We can use them for long time and contribute to the reduction of maintenance costs.