A quantitative analysis was carried out in the present study to determine the effects of titanium (Ti) addition on microstructures and strength of Nb-Ti microalloyed steel. The obtained results revealed that strength was significantly improved with an increase in Ti content from 0.041 to 0.079 wt pct. The difference in the yield strength between the two steel samples occurred due to the different strengthening effects of grain refinement, precipitation, and dislocation strengthening, among which the grain refinement and precipitation strengthening contributions were dominating. With a further increase in the Ti content, ferrite grains became refined. Consequently, a homogeneous ferrite microstructure was attained for high Ti contents. Moreover, large-sized (Ti, Nb)C particles manifested the Kurdjumov–Sachs (KS) relationship, whereas fine (Ti, Nb)C particles held the Baker–Nutting (BN) relationship; thus, abundant fine nanoscale (Ti, Nb)C particles formed after coiling. Furthermore, the high dislocation density facilitated the precipitation of (Ti, Nb)C particles along dislocation lines.

在本研究中进行了定量分析，以确定添加钛（Ti）对Nb-Ti微合金钢的组织和强度的影响。获得的结果表明，随着Ti含量从0.041wt。％增加到0.079wt。％，强度显着提高。两种钢样品的屈服强度差异是由于晶粒细化，析出和位错强化的强化效果不同而引起的，其中晶粒细化和析出强化的贡献占主导地位。随着Ti含量的进一步增加，铁素体晶粒变得细化。因此，对于高的Ti含量，获得了均匀的铁素体显微组织。此外，大尺寸（Ti，Nb）C颗粒表现出Kurdjumov–Sachs（KS）关系，而精细（Ti，Nb）C粒子保持贝克-坚果（BN）关系。因此，在卷取后形成大量的细小纳米级（Ti，Nb）C颗粒。此外，高位错密度促进了（Ti，Nb）C颗粒沿位错线的沉淀。