UNS S31035 A new austenitic tube grade for use in coal fired boilers at material temperatures up to about 700°C

摘要

In collaboration with different industrial actors within the European Thermie-project, a new austenitic stainless steel has been developed for use in advanced coal fired power boilers.The grade is designed for high creep- and oxidation resistance, high structural stability and good fabricability. It can be utilized at temperatures up to around 700°C. The temperature strength is reached by precipitate strengthening through precipitation of fine Nb(C,N), NbCrN, M_(23)C_6 and Cu-rich precipitates.The so far obtained test results indicate that this grade has high oxidation resistance and higher mechanical properties than other known austenitic stainless steels. This paper presents the properties and results from manufacturing and testing during the development and verification of data for the new grade. Also, some results from test installations in coal fired boilers are presented.Code cases as per The American Society of Mechanical Engineers Boiler and Pressure Vessel Code, Section I and Section VIII, are filed for.