Ti-V-Nb微合金管线钢中的第二相粒子分析

ANALYSIS OF SECONDARY PHASE PARTICLES IN Ti-V-Nb MICROALLOYED LINEPIPE STEEL

利用萃取复型分析技术 ,对Ti V Nb微合金管线钢中第二相粒子进行了研究。结果表明 ,钢中存在大量弥散分布的细小粒子 ,尺寸较大的粒子近似方形 ,含Ti量较高而含Nb量较低 ;尺寸较小的粒子形状不规则 ,含Ti量较低、含Nb量较高 ;尺寸在 2 0nm以上的粒子中含V量均较低。电子衍射分析表明 ,粒子具有面心立方结构。这些弥散分布的粒子能够显著阻止奥氏体晶粒长大 ,在 1 1 50℃以下加热时 ,该钢的奥氏体晶粒长大速度非常小 ,而在1 1 50℃以上的温度加热时 ,奥氏体晶粒长大较明显。

The secondary phase particles in Ti-V-Nb microalloyed linepipe steel were investigated using carbon extraction-replica technique.The results show there are a large number of fine dispersed particles in the steel.The larger particles like square contain higher Ti and lower Nb.The smaller particles of irregular shape contain lower Ti and higher Nb. The particles of more than 20nm size contain lower V. The electron diffraction analysis shows the particles have face-centered cubic structure. The dispersed particles retard the growth of austenite grains markedly.The austenite grains in the steel heated at below 1?150?℃ grow at very low speed .The austenite grains in the steel heated at above 1?150?℃ grow markedly.