氮含量对HPD-1双相不锈钢组织及力学性能的影响

Effect of nitrogen content on microstructure and mechanical properties of HPD-1 duplex stainless steel

通过显微组织观察与力学性能测试研究了氮含量(0.08%~0.22%,质量分数)对HPD-1双相不锈钢硬度、拉伸性能、低温冲击性能及疲劳性能的影响。结果表明,氮含量变化可显著影响试验钢γ/α相比例,当氮含量由0.08%升高到0.22%,γ相含量由38.1%提高至56.5%。α相的硬度由273 HV10提高到343 HV10,γ相的硬度由238 HV10提高到299 HV10,试验钢强度明显提升。氮元素对两相比例和奥氏体相韧性的双重影响导致试验钢低温冲击性能呈先上升后下降的趋势;更高的氮含量抑制疲劳裂纹萌生与拓展,是影响HPD-1双相不锈钢室温疲劳性能的主要因素。撕裂棱是疲劳断口的显著特征。

Effect of nitrogen content on hardness,tensile properties,low temperature impact toughness and fatigue properties of HPD-1 duplex stainless steel in the range of 0.08 wt%-0.22 wt% were studied by means of microstructure observation and mechanical properties testing.The results show that theγ/αphase ratio of the tested steel is significantly affected by the nitrogen content,when the nitrogen content is increased from 0.08 wt% to 0.22 wt%,the content ofγphase is increased from 38.1% to 56.5%.The hardness ofαphase is increased from 273 HV10 to 343 HV10,and that ofγphase is increased from 238 HV10 to 299 HV10,resulting in the strength of the tested steel being dramatically improved.The low temperature impact properties of the tested steel is increased at first and then decreased,which is caused by the combined influence of nitrogen on the two phase ratio.The fatigue crack initiation and propagation can be inhibited due to a higher nitrogen content,which plays an important role in the fatigue performance at room temperature of the HPD-1 duplex stainless steel,meanwhile the tearing edge is the main characteristic of fatigue fracture.