38MnSiVS非调质钢的相变模型

 对于热轧非调质钢棒材,轧后相变组织对最终产品的力学性能有着重要影响。为了准确预测38MnSiVS非调质钢棒材热轧后的组织演变和性能,利用热膨胀与定量金相方法,在Gleeble-3500热模拟机及Dil805淬火变形膨胀仪上分别测定了试验钢动态连续冷却转变(CCT)和动态等温转变(TTT)曲线。研究分析了冷却速率对试验钢相变及珠光体片层间距的影响,基于Esake and Pietrzyk和Zener and Hillert模型,分别建立了铁素体晶粒尺寸d_α、珠光体片层间距S_P关系式。结合动态等温转变曲线数据和Scheil叠加原理对铁素体体积分数进行了理论计算,为实际热轧生产中的组织性能控制提供理论依据。

Phase transformation model of 38MnSiVS non-tempered steel

For hot-rolled non-tempered steel bars,the transformation microstructure after rolling has an important influence on the mechanical properties of the final products.In order to predict the microstructure evolution and properties of 38 MnSiVS non-tempered steel bar after hot rolling accurately,the dynamic continuous cooling transformation(CCT)curve and dynamic isothermal transformation(TTT)curve was measured respectively using a thermal expansion method with a Gleeble-3500 thermal simulator and a Dil805 quenching dilatometer and analyzed by quantitative metallographic method of the microscopy.The effect of cooling rate on the phase transformation and pearlite interlamellar spacing was studied and analyzed,based on the Esake and Pietrzyk and Zener and Hillert models,then the relationships between the ferrite grain size d_α and pearlite interlamellar spacing S_P were established.In addition,combined with the data of dynamic isothermal transformation curve and Scheil superposition principle,the volume of ferrite is calculated theoretically,which is helpful microtructure and property control technology for hot rolling production.