Method to Improve Steel Creep Strength by Alloy Design and Heat Treatment

The operating efficiency of coal-fired power plants is directly related to combustion system temperature and pressure. Incorporating advanced ultrasupercritical (AUSC) steam conditions into new or existing power plants can increase power plant efficiency while reducing coal use, and by implication reducing carbon dioxide emissions. Under AUSC conditions, system components like boilers and turbines are exposed to a variety of extremely high temperatures and pressures—aggressive oxidizing and reducing environments in the boiler and oxidizing conditions in the turbine, that either shorten component lifespan or require the use of thicker components or more costly alloys, resulting in increased cost with little or no improvement in cycle efficiency. Conventional commercial materials do not possess the optimal characteristics for operation under the more stringent AUSC conditions. Therefore, advanced, higher temperature capable steels and novel manufacturing processes are needed to develop these alloys as well as other metallic heat resistant materials for use in these extreme conditions.