The oxide metallurgy was employed in the fabrication of twin-roll strip casting low carbon steels. The quantitative dependences of the microstructure and mechanical properties on cooling parameters were revealed and emphatically investigated. After twin-roll strip casting, a two-step cooling route closed to the actual process was designed and the cooling rates exhibited great influences on the proportion of polygonal ferrite (PF) and acicular ferrite (AF). With increasing cooling rates in both steps, the AF volume fraction raised from 0.04 to 0.75 because the rapid cooling restrained the formation of PF. The AF laths were induced by fine Al–Si–Ti–Mn composite oxides (0.2–2 μm), leading to a heterogeneous microstructure consisting of PF and AF clusters with high proportion of large-angle (≥15°) grain boundaries. It was found that the AF laths kept K–S relationship with austenite and AF laths with collinear growth direction belong to the same codirectional variants group in one AF cluster. With the increase of AF volume fraction, the yield strength (YS) and the ultimate tensile strength (UTS) were improved, while the strip retained excellent elongation. The improved YS was mainly ascribed to the grain boundary strengthening and dislocation strengthening.

氧化物冶金学用于双辊薄带连铸低碳钢的制造。揭示并着重研究了微观结构和力学性能对冷却参数的定量依赖性。在双辊薄带连铸之后，设计了一个与实际工艺接近的两步冷却路径，并且冷却速率对多边形铁素体（PF）和针状铁素体（AF）的比例显示出很大的影响。随着两个步骤中冷却速度的提高，AF体积分数从0.04上升至0.75，因为快速冷却抑制了PF的形成。AF板条由细小的Al–Si–Ti–Mn复合氧化物（0.2–2μm）诱导，导致由PF和AF团簇组成的异质微观结构，且具有大比例的大角度（≥15°）晶界。结果发现，AF板条与奥氏体保持K–S关系，并且共线生长方向的AF板条在一个AF簇中属于同一同向变体组。随着AF体积分数的增加，屈服强度（YS）和极限拉伸强度（UTS）得到改善，而带材保持了优异的伸长率。改进后的YS主要归因于晶界强化和位错强化。