Creep and LCF Behaviors of Newly Developed Advanced Heat Resistant Austenitic Stainless Steel for A-USC

Austenitic stainless steel grade UNS S31035 (Sandvik Sanicro® 25) has been developed for use in super-heaters and reheaters in the next generation of A-USC power plants. This new grade shows very good resistances to steam oxidation and hot corrosion, and higher creep rupture strength than other austenitic stainless steels available today. This makes it an interesting alternative for super-heaters and reheaters in future high-efficient coal fired boilers. This paper will mainly focus on the study of the creep and LCF behavior of the material at temperatures from 600 °C to 750 °C by using TEM and ECCI. The mechanisms at different temperatures and loading conditions have been identified. The interactions between dislocations and precipitates and their contribution to the creep rupture strength have been discussed. In this paper, different models have been used to evaluate the long-term creep behavior of the grade. A creep rupture strength near 100 MPa at 700 °C for 100 000 h has been predicted.