1 Institute for Special Steels, China Iron and Steel Research Institute, Beijing 100081, China 2 Collaborative Innovation Center of Steel Technology, University of Science and Technology Beijing, Beijing 100083, China 3 Science and Technology on Reactor System Design Technology Laboratory, Nuclear Power Institute of China, Chengdu 610041, Sichuan, China 4 Southern Additive Science and Technology Co., Ltd., Foshan 528225, Guangdong, China
Microstructure and impact toughness of 16MND5 reactor pressure vessel steel manufactured by electrical additive manufacturing
1 Institute for Special Steels, China Iron and Steel Research Institute, Beijing 100081, China 2 Collaborative Innovation Center of Steel Technology, University of Science and Technology Beijing, Beijing 100083, China 3 Science and Technology on Reactor System Design Technology Laboratory, Nuclear Power Institute of China, Chengdu 610041, Sichuan, China 4 Southern Additive Science and Technology Co., Ltd., Foshan 528225, Guangdong, China
摘要 Electrical additive manufacturing can improve manufacturing efficiency and reduce the cost of 16MND5 reactor pressure vessel steel. Impact tests were conducted to compare the impact toughness of 16MND5 steels manufactured by the electrical additive manufacturing and conventional forging, respectively. It is found that the impact toughness of electrical additive manufacturing specimen was slightly higher than that of conventional forging specimen. The characterizations of microstructure show that there were large ferrites and carbides in electrical additive manufacturing specimen. The fracture mechanisms of electrical additive manufacturing specimen were that microvoids or microcracks were prone to nucleate at the large ferrite/bainite interface and large carbide/bainitic ferrite interface, where the stress concentration was high. In addition, the block size and high-angle grain boundaries played a vital role in hindering crack propagation of electrical additive manufacturing specimen, helping to improve the impact energy and leading to a low ductile–brittle transition temperature. The results suggest that the electrical additive manufacturing technology was an effective method to enhance the impact toughness of 16MND5 steel.
Abstract：Electrical additive manufacturing can improve manufacturing efficiency and reduce the cost of 16MND5 reactor pressure vessel steel. Impact tests were conducted to compare the impact toughness of 16MND5 steels manufactured by the electrical additive manufacturing and conventional forging, respectively. It is found that the impact toughness of electrical additive manufacturing specimen was slightly higher than that of conventional forging specimen. The characterizations of microstructure show that there were large ferrites and carbides in electrical additive manufacturing specimen. The fracture mechanisms of electrical additive manufacturing specimen were that microvoids or microcracks were prone to nucleate at the large ferrite/bainite interface and large carbide/bainitic ferrite interface, where the stress concentration was high. In addition, the block size and high-angle grain boundaries played a vital role in hindering crack propagation of electrical additive manufacturing specimen, helping to improve the impact energy and leading to a low ductile–brittle transition temperature. The results suggest that the electrical additive manufacturing technology was an effective method to enhance the impact toughness of 16MND5 steel.
Xi-kou He,Chang-sheng Xie,Li-jun Xiao, et al. Microstructure and impact toughness of 16MND5 reactor pressure vessel steel manufactured by electrical additive manufacturing[J]. Journal of Iron and Steel Research International, 2020, 27(8): 992-1004.
2020, Vol. 27 
