加热温度对低碳微合金钢相变的影响

Influence of Heat Temperature on Transformation of Low Carbon Microalloyed Steel

采用Gleeble-1500热模拟机对低碳Mn-Nb-Ti钢进行了不同加热温度下的奥氏体变形和变形后的冷却实验,通过光学显微镜和扫描电镜分析了加热温度对奥氏体有效晶粒尺寸的影响,和不同有效晶粒尺寸的奥氏体相变后显微组织的变化。结果表明,随着加热温度的提高,变形奥氏体的有效晶粒尺寸增大;相变后的显微组织中铁素体由等轴状逐渐过渡到准多边形以至形成长条状,微细碳化物逐渐减少,小岛逐渐增多,小岛的长宽比不断增大最后形成细长条状。

A series of experiments that austenite deforming as well as consequent cooling under the different heat temperature were carried out by using Gleeble1500 thermomechanical simulator for low carbon Mn-Nb-Ti steel. The change of effective austenite grain size at different heat temperature and microstructure change transformed on various effective austenite grains size were analyzed by means of OM and SEM. The results show that with increasing the heat temperature, the deformed austenite effective grains size increases, among the transformed microstructure ferrite varies from equiaxed shape to quasi-polygon even to slightness shape, the micro-carbide gradually reduces, the islet gradually increases, the islet's ratio of length to wide gradually increases, and at least forms thinning slightness.