【摘要】 采用Gleeble 2000高温力学性能模拟实验机对不同冷却速率及不同拉伸速率下600 MPa级Al-Mo系冷轧双相钢高温热塑性进行了研究。结果表明,随拉伸应变速率增大,双相钢的高温热塑性明显提高;降低冷却速率,能显著提高双相钢高温区(t>1100℃)的塑性性能。为了避免铸坯在连铸过程中产生表面裂纹,矫直温度应保证在1050~1150℃范围内,同时二次冷却应采用弱冷水制度,以降低冷却速率。金相观察发现,沿奥氏体晶界呈网状分布的铁素体薄膜是造成两相区塑性低谷的主要原因,而AlN、FeO等析出相致使奥氏体单相区脆化。更多还原

【Abstract】 By using Gleeble 2000 thermal simulation test machine,the hot ductility of cold-rolled dual phase steel in Al-Mo series had been researched at the different strain rate and different cooling rate.The results indicated that with the increase of the strain rate the hot ductility of the steel can be improved and with the decrease of the cooling rate the hot ductility in the high temperature zone(t>1 100 ℃) can be obviously improved as well;In order to avoid the occurring of the surface cracking on the continuous casting slab,the straightening temperature during the continuous casting process should be maintained at temperature ranging from 1 050 to 1 150 ℃ and for the second cooling water,the soft cooling system should be used so as to increase the hot ductility.The research of the microstructure showed that the filmy and network ferrite which generated along the austenite grain boundary during the transformation process of austenite-to-ferrite and the and precipitation existed along the austenite grain boundary were the main reasons for the decrease of the hot ductility of the steel.On the basis of the results of the microstructure the mechanism of the effect of the strain rate and the cooling rate on the hot ductility had been discussed.更多还原