Characteristics of Fusion-Welded Joints Made Using Martensitic Steel after 100,000 Hours in Service

摘要

The paper presents the results of tests of mixed fusion-welded joints consisting of superheater pipes of grades T91 and T122(HCM12A) after 100,000 hours in service in a BB-1150 boiler welded to new pipes (in "as-delivered" condition) of grades T91 and VM12-SHC. The state of the microstructure and properties of the used tube material after long term service are characterized. The paper describes fusion welding conditions and parameters, and evaluates the quality of the created butt joints. The results of tests of the macro- and microstructure of the joints and their mechanical properties are presented. It was determined that the welding process intensifies further degradation of the tested materials to a small extent only. This work was performed under the Strategic Research Project No SP/E/1/67484/10 supported by the National Centre for Research and Development.