The microstructure and tensile property changes of S31042 steel after long time service

Abstract

Ultra-supercritical power generation technology is one of the main solutions to the many contradictory problems of carbon emissions and environmental protection in coal-fired power plants. S31042 austenitic heat-resistant steel has become a typical material for high-temperature components used in ultra-supercritical units because of its good high-temperature creep properties and high-temperature corrosion resistance. In this study, typical characterization techniques such as SEM (Scanning Electron Microscopy), TEM (transmission electron microscopy), and EBSD (Electron Backscattered Diffraction) were used to observe the microstructure of S31042 austenitic heat-resistant steel, while the room-temperature tensile and high-temperature tensile properties of the material were tested under the corresponding conditions. The results show that the grain of S31042 heat-resistant steel after service is the same as that of the non-service samples, which is still twinned austenite. The room-temperature tensile properties and high-temperature tensile properties of S31042 after long service were almost unchanged.

Embrittlement Mechanisms of HR3C Pipe Steel at Room Temperature in Ultra-Supercritical Unit

“…However, with an extension in service time, the elongation of the alloy after breaking decreased significantly. Further research results show that the precipitated nano-phase at high temperature is the reason why HR3C has excellent tensile properties at high temperature [3,[19][20][21]. The ultimate tensile resistance of HR3C steel is one of the mechanical properties that need to be tracked during its service.…”

“…Ultra-supercritical units are currently the most efficient coal-fired generating units because of their high steam pressure and temperature [1][2][3]. HR3C steel is a kind of pipe steel obtained by adding Nb and N elements to 25Cr-20Ni austenitic steel from Sumitomo Corporation of Tokyo, Japan, and is widely used in ultra-supercritical power plant boilers due to its high-temperature strength, oxidation resistance and corrosion resistance [4][5][6][7].…”