Hot ductility behavior of V-N and V-Nb microalloyed steels

Bing-hua Chen and Hao Yu School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China

摘 要：The hot ductility of V-N and V-Nb microalloyed steels was investigated on a Gleeble-1500 thermomechanical simulator, and the results were compared with those of V and Nb microalloyed steels. A ductility trough is found in both the steels in the temperature range of 700 to 1050°C. Compared to the V steel, the V-N steel has a wider and deeper ductility trough with the increase of N content, due to the in-creased precipitation of V（C, N） in the steel. Above 930°C, when 0.047wt% V is added to the 0.028wt% Nb-containing steel, the ductility becomes worse, owing to the rise of the onset dynamic recrystallization temperature. However, the ductility gets better at 800 to 930°C be-cause of the coarsening of precipitates in austenite. With the improvement in ductility, the fracture mechanism is changed from intergranular to high ductile fracture in the temperature range of 800 to 1050°C.

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