C-Mn-Cr系冷轧热镀锌双相钢高温力学性能及热力学研究
Study on High-temperature Mechanical Properties and Thermodynamics of C-Mn-Cr Cold-rolled Hot-galvanize Dual Phase Steel
王科强1, 刘仁东1, 韩启航2, 王 旭1
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作者单位：1. 鞍钢股份有限公司 技术中心, 辽宁 鞍山 114009; 2. 北京科技大学 材料学院, 北京 100083
中文关键字：热镀锌； 双相钢； 高温力学性能； 相组成； 热力学
英文关键字：hot-galvanize; dual phase steel; high-temperature mechanical properties; phase composition; thermodynamics
中文摘要：通过Thermo-Calc热力学计算软件结合Gleeble-3800热/力模拟试验机，研究了C-Mn-Cr系冷轧热镀锌双相钢的高温力学性能及热力学行为。采用圆柱试样压缩的方法，分析了实验钢在不同变形条件下热变形抗力的变化规律。结果表明：热变形抗力随变形量、变形速率的增加而增加，随温度的升高而降低，并且这种态势随变形温度、变形速率的提高逐渐趋缓。通过热力学计算，C的活度随铁素体相变变化较大，而Fe的活度随温度降低缓慢升高，Si、Mn、Cr的活度随温度变化不大。此外，热变形通过改变奥氏体的晶界能和位错能，使得渗碳体和M7C3相在不同温度下各合金元素扩散速度加快，因而加剧了相组成的重排过程。
英文摘要：By Thermo-Calc software calculation and compressing cylinder samples on Gleeble-3800 thermal analog test machine, the high-temperature mechanical properties and thermodynamics of C-Mn-Cr cold-rolled hot-galvanize dual phase steel were studied. The results show that the thermal deformation resistance rises with the increase of the thermal deformation rate and amount, and falls with the increase of deformation temperature, and the state slackens at higher temperature or higher deformation rate. Besides, the activity of C changes significantly with the ferrite trans-formation. And the activity of Fe increases with the decrease of temperature, while it is not obvious on Si, Mn and Cr. Moreover, the grain boundary energy and dislocation energy are changed by hot deformation, which promotes the diffusion of cementite and M7C3 phase at different temperature. As a result, the rearrangement process of phase composition is accelerated.