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利用碳萃取复型、TEM和EDX分析,研究了低碳Nb-Ti微合金钢在1 300℃等温过程中第二相粒子的溶解行为。实验结果表明:钢中有两类尺度存在显著差异的析出颗粒,其一为尺寸在50 nm以上的富钛相(生成于钢液凝固阶段),其二为尺寸小于20 nm的富铌相(形成于奥氏体变形过程)。在1 300℃保温2 h后,应变诱导析出相基本消失,而凝固过程中形成的析出相在保温48 h后,还存在含Nb的(Nb,Ti)(C,N)复合相。在微合金钢中含Ti的情况下,碳氮化物的稳定性大幅提高。这些结果表明,析出相的形成和热稳定性在很大程度上取决于Nb和Ti原子的相互作用。
The dissolution behavior of the second phase particles in the low-temperature Nb-Ti microalloyed steel at 1300 ℃ isothermally studied by means of carbon compounding, TEM and EDX analysis. The experimental results show that there are two types of precipitated grains with significant difference in scale, one of which is a titanium-rich phase (formed in the solidification stage of molten steel) with a size above 50 nm and the other is a niobium-rich phase with a size of less than 20 nm Formed in the austenite deformation process). At 1 300 ℃ for 2 h, the strain-induced precipitation basically disappeared. However, the (Nb, Ti) (Nb, Ti) (C, N) -containing phase containing Nb also existed after 48 h of solidification. In the case of microalloyed steels containing Ti, the stability of carbonitrides is greatly increased. These results indicate that the formation and thermal stability of the precipitates depend to a large extent on the interaction of Nb and Ti atoms.