After 2002, China's large-scale thermal power projects mainly in the development of high-efficiency, high parameters supercritical (SC) and ultra-supercritical (USC) thermal power units. Currently,China have more than 100 sets of supercritical units. Because of equipment design requirements, SC and USC thermal power units must use once-through boiler, manufactured by austenitic steel. To avoid chemical cleaning process chlorine brittle phenomenon, this type can only be used when organic chemical cleaning eq...