冷轧低碳钢快速加热过程中的相变规律

以两种不同成分冷轧低碳钢为研究对象,利用Gleeble-3800热/力模拟实验机,研究了冷轧低碳钢在快速加热条件下,加热速度、化学成分对加热过程中相变规律的影响及连续加热过程中奥氏体晶粒尺寸的演变.研究结果表明,随着加热速度的增加(5~500℃/s),实验钢相变点的升高趋势先快后慢,100℃/s为转折点.在连续加热过程中存在奥氏体晶粒异常长大的温度转折点,为1 050℃;在850~950℃范围内,奥氏体平均晶粒尺寸均小于5μm;添加微合金元素有利于细化奥氏体晶粒.研究结果为利用快速加热、短时保温的方法获得冷轧超细晶钢提供了参考依据.

Phase Transformation Law of Cold-Rolled Low Carbon Steel During Rapid Heating

For two cold-rolled low carbon steel with different compositions,the effects of heating rates and specimens’ compositions on phase transformation during rapid heating were investigated using Gleeble-3800 thermal simulation testing machine,as well as the evolution of austenite grain size.The results show that the phase transformation temperature increases rapidly with increasing the heating rate from 5 to 100 ℃/s and then slowly from 100 to 500 ℃/s.There is a key temperature during continuous heating,i.e.,1 050 ℃,at which austenite grains begin to grow abnormally.The average grain size is less than 5 μm at 850—950 ℃.Adding alloy elements is beneficial to refining austenite grains.The results provide a reference to obtain the cold-rolled ultrafine grained steel using the method of rapid heating followed by holding for a short time.