低碳钢回火过程中Cu、Nb析出的相互作用

Interaction between precipitation of Cu and Nb of low carbon steels during tempering

研究了两种不同成分的低碳钢在600℃条件下经不同时间回火处理后的硬度变化,并对600℃回火18 h的样品析出物进行组织观察、TEM观测及粒度统计。结果表明:C-Nb钢和C-Cu-Nb钢在600℃条件下,短时间回火硬度趋势相反,长时间回火硬度趋势平缓,说明Cu和Nb的析出过程独立存在,析出时间和规律不同;C-Cu-Nb钢中Nb析出物颗粒尺寸明显大于C-Nb钢,说明Cu的添加促进了Nb析出物的长大。

Hardness of two low carbon steels with different compositions upon tempering at 600 ℃ for different time was studied. The precipitates of samples tempering at 600 ℃ for 18 h were analyzed by using metallographic observation,TEM technique and particle size statistics. The results show that the hardness trend of C-Nb steel and C-Cu-Nb steel is opposited at the beginning of tempering and then become stable during a wide time range,which indicates that the precipitation process of Nb and Cu is independent,and the time and law of precipitation are different; the particle size of the precipitates in C-Cu-Nb steel is significantly larger than that of C-Nb steel tempering at 600 ℃ for18 h,and the addition of Cu enhances the growth of Nb C particles.