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.

电气增材制造可以提高制造效率并降低16MND5反应堆压力容器钢的成本。进行了冲击试验，以比较分别通过电子增材制造和常规锻造制造的16MND5钢的冲击韧性。发现，电添加剂制造试样的冲击韧性略高于常规锻造试样。显微组织的表征表明，在电气增材制造样品中存在大量的铁素体和碳化物。电气添加剂制造样品的断裂机理是，在应力集中较高的大铁素体/贝氏体界面和大碳化物/贝氏体铁素体界面处，微孔或微裂纹易于成核。此外，块体尺寸和高角度晶界在阻碍电气增材制造样品的裂纹扩展方面起着至关重要的作用，有助于改善冲击能并导致较低的韧性-脆性转变温度。结果表明，电熔增材制造技术是提高16MND5钢冲击韧性的有效方法。