Hot deformation behavior and processing map of a Fe‐25Ni‐16Cr‐3Al alumina‐forming austenitic steel

The hot deformation behavior of a Fe‐25Ni‐16Cr‐3Al alumina‐forming austenitic steel was studied by hot compression using a Gleeble‐3500 thermal simulator. The compression tests were carried out in the temperatures range from 925 °C to 1175 °C and strain rates range from 0.01 s^‐1 to 10 s^‐1. It was concluded that the flow stress increased with decreasing deformation temperature and increasing strain rate. The constitutive equation was obtained and the activation energy was 420.98 kJ?mol^‐1 according to the testing data. According to the achieved processing map, the optimal processing domain is determined in the temperatures range of 1050 °C – 1075 °C and strain rates range of 0.03 s^‐1 ‐ 0.3 s^‐1. The evolution of microstructure characterization is consistent with the rules predicted by the processing map. During compression at the same temperature, the higher the strain rate is, the higher the hardness will be. The ultimate tensile strength of the steel is 779 MPa with a total elongation of 27.1 % at room temperature.