利用Gleeble-3500热变形模拟试验机研究了中等铌含量(0.05%)低碳微合金钢的高温塑性。结果表明,试验钢在1350℃以上区域为第一高温塑性低谷;介于1250~950℃,出现一个高温塑性很好的区域,断面收缩率达到60%以上;而介于750~650℃则为第二高温塑性低谷。此外,铌可降低奥氏体向铁素体的转变温度,扩大奥氏体单相区,从而使试验钢第二高温塑性的低谷左移。 The high temperature ductility of low carbon microalloyed steel with medium niobium content (0.05%) was studied by Gleeble-3500 thermal deformation simulator. The results show that the test steel is the first high temperature ductile trough in the region above 1350 ℃. When the temperature is in the range of 1250 ~ 950 ℃, there is a region of good high temperature plasticity with the reduction of area above 60%, while the range of 750-650 ℃ Second high temperature plastic trough. In addition, niobium can reduce the austenite to ferrite transformation temperature, expanding the austenite single-phase zone, so that the test steel second high-temperature plasticity left shift.