Development of a new high-performance martensitic heatresistant steel for boiler applications

Abstract

The realization of advanced thermal power plants with increased efficiencies requires the development of new materials with enhanced capabilities in respect to high temperature strength and steam oxidation behavior. The change in the environmental policy and the increasing contribution of renewable energy sources into the public electric grid has changed the operation mode of the existing power plants in Europe. Instead of quasi stationary operation, for which the conventional thermal power plant fleet was designed, cyclic operation modes will dominate the power plant service lifetime. The creep-fatigue phenomena, however, may be responsible for significant lifetime reductions compared with the original design lifetime. Revamping of the existing power plants by application of "stronger" materials with improved steamoxidation behavior, allowing wall thickness reduction can be a possible way to address the topic. Recently, Vallourec developed a new high-Cr ferritic-martensitic steel that combines excellent creep rupture strength properties and enhanced steam oxidation resistance of 12%Cr steels such as VM12-SHC or X20CrMoV11-1. Industrial products were successfully manufactured and the creep and steam oxidation properties were validated.