30CrMnSiA合金结构钢电流辅助单向压缩流变行为

Flow behaviors of 30CrMnSiA alloy structural steel during current assisted uniaxial compression

以30CrMnSiA合金结构钢为研究对象,对其在脉冲电流作用下的单向压缩流变行为进行了研究,设计了“导电块-上下压块-导电块”的电流施加方案,提出采用压缩空气进行冷却的方法消除焦耳热的影响,分析了脉冲电流参数(脉冲电流密度、脉冲占空比和脉冲频率)对30CrMnSiA合金结构钢流变行为的影响规律。基于Voce加工硬化模型,构建了脉冲电流辅助下30CrMnSiA合金结构钢的电致塑性本构模型,并进行了试验验证。结果表明,30CrMnSiA合金结构钢的流变应力随着脉冲电流密度、脉冲占空比以及脉冲频率的升高而降低,脉冲电流密度的变化对材料流变应力的影响最为显著;通电条件下材料的加工硬化指数n高于不通电时,且随电流密度与占空比的升高而升高,随脉冲频率变化不明显;利用构建的本构模型计算的流变应力值与试验数据的误差在6%以内,说明该模型能较好地预测30CrMnSiA合金结构钢电流辅助压缩类成形时的流变行为。

The uniaxial compression flow behaviors of 30CrMnSiA alloy structural steel under pulse current were studied.A current appli⁃cation scheme of“conductive block⁃upper and lower pressure block⁃conductive block”was designed,and a method of using compressed air for cooling was proposed to eliminate the effect of Joule heat.The influence laws of pulse current parameters(pulse current density,pulse duty cycle and pulse frequency)on the flow behaviors of 30CrMnSiA alloy structural steel were analyzed.The electroplastic constitu⁃tive model of 30CrMnSiA alloy structural steel with the assistance of pulse current was constructed based on the Voce work hardening mod⁃el and verified by tests.The results show that the flow stress of 30CrMnSiA alloy structural steel decreases with the increase of pulse cur⁃rent density,pulse duty cycle and pulse frequency,and the change of pulse current density has the most significant influence on the flow stress of material.The work hardening exponentnof the material with pulse current is higher than that without pulse current,and it in⁃creases with the increase of current density and duty cycle,while the change with frequency is not obvious.The error between the flow stress values calculated by using the constructed constitutive model and the test data is within 6%,indicating that the model can effectively predict the flow behaviors of 30CrMnSiA alloy structural steel during current assisted compression forming.