Double compression tests are carried out to investigate the microstructural evolution and precipitation behavior of Nb–Ti microalloyed carbide‐free bainitic steel under different finish rolling conditions. With decreasing finish rolling temperature and increasing finish rolling deformation, the area fraction of lath bainite (LB) and martensite (M) was increased, the width of bainitic ferrite lath was decreased, the dislocation density and the number fraction of high‐angle grain boundaries are raised. Meanwhile, the larger deformation and lower temperature reduce the amount of retained austenite (RA) and refine the precipitated particles, which benefit the performance further. Hence, the phase transformation strengthening, refinement strengthening, dislocation strengthening, and precipitation strengthening synergistically contribute to the increase in hardness with increasing deformation and decreasing temperature.

中文翻译：

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终轧温度和变形对非调质无回火贝氏体钢组织演变和析出行为的影响

进行了两次压缩试验，以研究不同精轧条件下Nb-Ti微合金无碳化贝氏体钢的组织演变和析出行为。随着终轧温度的降低和终轧变形的增加，板条贝氏体（LB）和马氏体（M）的面积分数增加，贝氏体铁素体板条的宽度减小，位错密度和高角度晶界的数量分数被提出。同时，较大的变形和较低的温度降低了残余奥氏体（RA）的量并细化了沉淀的颗粒，这进一步有利于性能。因此，相变强化，细化强化，位错强化，