Evaluation of Thermal Aging Effect on Primary Pipe Material in Nuclear Power Plant by Micro Hardness Test Method

The investigation was carried out on the changes in mechanical properties of the primary pipe material Z3CN20.09M after 10 000 h aging at 400 ℃ by using micro-Vickers and impact testing machine. The results show that the impact energy of testing material decreases. However, the micro-Vickers hardness of ferrite phase and austenite phase which constitute the testing material increase and keep constant, respectively. The intrinsic relations were analyzed between the micro-Vickers hardness and the impact energy to make an attempt to present the micro-Vickers hardness measurement as a method applicable to evaluating the thermal aging of the primary pipe material.