| The hot deformation in the range of 900℃∼1000℃, 0.05/sec∼1.15/sec were performed to study the effect of dynamic recrystallization in the controlled rolling of Nb-microalloyed structural was steel with decreasing temperature (T), increasing strain rate(ε), and pass strain (ε₁) of 0.2 and /or 0.5. The flow stress dependence(σ) of T, ε, and strain(ε) is also exaned. The critical strain of dynamic recrystallization(ε_o) was determined from the Lnσ/Lnε vs. ε plots. The Brain refinement can be obtained by progressing the process and controlling the degree of dynamic recrystallization. By increasing the pass stain from 0.2 to 0.5 at the penultimate deformation step in this process, dynamic recrystallization could be induced. |
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