Indentation Relaxation Behavior of the Austenitic Heat-Resistant Steel Sanicro25

Dalian University of Technology, 116086 Dalian, China

^* Corresponding author: tieshan@dlut.edu.cn

Abstract

Taking sanicro25, an austenitic heat-resistant steel for ultra-supercritical power stations, as the research object, a new electronic creep tester is used to conduct indentation experiments at high temperatures to evaluate the feasibility of its indentation relaxation performance; the indentation experiments are conducted using a Vickers indenter, and the high-temperature relaxation creep behavior is investigated in the range of temperatures and depths of indentation from 973-1073K and 100-180 μm, and the relaxed The results show that: the indentation at different depths is not easy. The results show that: the hardness/stress and time patterns of indentation relaxation at different depths are in accordance with the relationship similar to that proposed by Choi; the stress index is about 7 according to the power rate relationship, and the relaxation coefficient μ is about 0.3, whose inverse matches well with the stress index obtained from the indentation creep test; there is a pile-up phenomenon at the edges of the residual indentation on the surface of the specimen, which is caused by plastic flow of the material along the direction of the indenter after the formation of a completely plastic region at the bottom of the indenter. Plastic flow occurs along the indenter direction after the material forms a fully plastic region at the bottom of the indenter.