降低冷轧取向硅钢残余应力和位错密度的磁-热耦合工艺

Magnetic-thermal coupling to reduce residual stress and dislocation density of cold-rolled oriented silicon steel

为了得到一种高效去除冷轧取向硅钢残余应力的工艺,制定了低温、低强度脉冲磁场的短时磁-热耦合处理试验方案,分别利用X射线残余应力仪和XRD测定了不同工艺处理前后取向硅钢的残余应力和位错密度。结果表明,采用低温、低强度脉冲磁场的短时磁-热耦合处理可以有效降低冷轧取向硅钢的残余应力和位错密度,当采用处理时间为3 min、处理温度为400℃、峰值电流为180 A的磁-热耦合工艺时,可取得最佳处理效果,残余应力降幅为55.5%,比单纯只施加低温热场或低强度脉冲磁场的处理效果优异。宏观残余应力的降低与位错密度具有紧密的联系,两者变化规律基本一致。短时、低温、低脉冲磁场强度磁-热耦合处理去除残余应力的微观机制是脉冲磁场和温度场耦合作用下进一步提高材料内部位错运动,实现了局部回复,达到位错密度和残余应力减小的目的。

In order to obtain an efficient process for reducing residual stress of cold-rolled oriented silicon steel,a short-time magnetic-thermal coupling treatment test scheme with low temperature and low intensity pulsed magnetic field was developed.The residual stress and dislocation density before and after the treatment were measured by X-ray residual stress meter and XRD,respectively.The results show that the short-time magnetic-thermal coupling process with low temperature and low intensity pulsed magnetic field can effectively reduce the residual stress and dislocation density of cold-rolled silicon steel.When the process is applied for 3 min at 400℃ and with the peak current of 180 A,the best treatment effect can be obtained,and the residual stress can be reduced by 55.5%,which is better than simply applying low temperature thermal field or low intensity pulsed magnetic field.The decrease of macro-residual stress is closely related to the dislocation density,and the change rule of the both is basically the same.The microscopic mechanism of residual stress reducing by short-time,low-temperature and low pulsed magnetic field intensity magnetic-thermal coupling treatment is that the dislocation movement in the material is further improved under the coupling action of pulsed magnetic field and temperature field,and the local recovery is realized,so as to achieve the purpose of reducing dislocation density and residual stress.