The study of the evolution of the microstructure and creep properties of Super 304H austenitic stainless steel after aging for up to 50,000 h

The paper discusses several aspects of degradation of Super 304H steel subjected to long-term aging up to 50,000 h at 650 and 750 degrees C. The study includes microstructure examination by scanning and transmission electron microscopy along with X-ray microanalysis of a wide range of precipitates. The Super 304H steel has a structure characteristic for austenitic steels with annealing twins and single primary NBX precipitates of various sizes. Long-term aging leads to precipitation of several phases such as M23C6, MX carbides, sigma phases, Z phase and epsilon-Cu phase. The precipitation processes lead to changes in the creep strength of the tested steel, the value of which strongly depends on the aging temperature used, which is measurably shown by the creep tests carried out with the elongation measured during the test.

Automated summary

The paper discusses the degradation of Super 304H steel subjected to long-term aging at high temperatures. The study examines the microstructure and various precipitates formed during aging. The precipitation of different phases affects the creep strength of the steel, which is dependent on the aging temperature.