电熔增材制造反应堆压力容器用16MND5钢的组织与力学性能

Microstructure and mechanical properties of 16MND5 RPV steel by electrical additive manufacturing

采用电熔增材制造技术打印了反应堆压力容器16MND5钢环件,并对其周向不同位置处的组织和性能进行了分析。结果表明:电熔增材制造反应堆压力容器16MND5钢环件的力学性能都满足RCC-M核电规范要求,强度和塑性均匀,没有明显尺寸效应,位错强化和弥散强化的综合作用使得材料的整体强度很高。周向3个位置的-20℃、0℃和20℃平均冲击吸收能量方差计算结果表明,在0℃时的平均冲击吸收能量没有明显的尺寸效应,而在-20℃和20℃时的平均冲击吸收能量有明显的尺寸效应,这与大尺寸铁素体或多边形状铁素体的存在,易成为裂纹扩展的通道有关。大量细小均匀分布的碳化物存在对冲击韧性有益,细晶强化作用显著提高材料的韧性,消除混晶则在现有的基础上进一步提升材料的冲击韧性。

The 16MND5 steel ring of reactor pressure vessel(RPV)was printed by electrical additive manufacturing technology,and the microstructure and properties at different circumferential positions were analyzed.The results show that the mechanical properties of 16MND5 steel ring in pressure vessel printed by electrical additive manufacturing meet the requirements of RCC-M nuclear power specification,the strength and plasticity are uniform,and there is no obvious size effect.The combination of dislocation strengthening and dispersion strengthening leads to very high overall strength of the material.The calculation results of the average impact energy variance at-20℃,0℃and 20℃in three circumferential directions shows that the average impact energy at 0℃has no significant size effect,while that at-20℃and 20℃has obvious size effect due to the presence of large-sized ferrite or polygonal ferrite as easy crack propagation path.A large number of fine and evenly distributed carbides are beneficial to the impact toughness,and the fine grain strengthening effect significantly improves the toughness of the material,and elimination of the mixed size grains further enhances the impact toughness of the material on the existing basis.