基于Arrhenius改进模型的无取向电工钢高温变形本构关系

High-temperature Constitutive Relationship of Non-oriented Electrical Steel Based on Modified Arrhenius Model

建立无取向电工钢热轧高温行为的统一本构关系模型。基于大型工业轧机取样的无取向电工钢连续冷却转变图分析测定,采用Gleeble热模拟试验机在750~1 120℃温度范围和0.05~10 s^(-1)应变速率范围进行热模拟试验。随着温度的降低,在1 120~975℃的奥氏体区,应力随之增加;975~875℃的奥氏体-铁素体两相区内,应力随之降低;875~750℃铁素体区内,应力随之增加;铁素体区以动态回复软化机制为主,而奥氏体区以动态再结晶为主,而且变形速率越大,动态再结晶越不明显,直至仅呈现动态回复型。基于Arrhenius改进模型框架,建立描述该钢种热连轧机粗轧机组和精轧机组完整轧制过程加工硬化与软化机制的统一本构关系,可精确地预测加工材料的属性。

For hot rolling,a comprehensive constitutive model is developed for high-temperature behaviors of non-oriented electrical steels.Based on the analysis of CCT curves of non-oriented electrical steels from the industrial hot rolling mills,by using the Gleeble thermal stress-stain simulator,the current study is focused on the temperature range from 750 to 1 120 ℃and the strain rate range from 0.05 to 10 per second.As temperature is lowered,in the austenite region（1 120-975 ℃）,the stress increases;in the austenite-ferrite region（975-875 ℃）,the stress decreases;and in the ferrite region（875-750 ℃）,the stress increases.In the ferrite region,dynamic recovery softening mechanism is most pronounced;in the austenite region,dynamic recrystallization tends to be the dominant process.If the deformation rate rises,dynamic recrystallization would be suppressed,and dynamic recovery would be promoted.In the framework of modified Arrhenius model,a constitutive relation is established describing the work hardening and softening mechanisms in the entire rolling procedure,which can predict quite precisely the properties of the processed materials.