材料期刊网

以取向电工钢成分为基础,制备了含C或Mn和S的4种实验钢。观察了接近平衡析出状态实验钢经60%冷轧后在600～1000℃范围再结晶退火过程中微观组织演变,统计分析了再结晶体积分数随退火时间的变化规律,进而计算了各实验钢静态再结晶的激活能。观察了高含C实验钢退火初期再结晶晶粒优先出现的部位。结果表明900～1000℃范围内各实验钢铁素体的化学成分相似,因而其再结晶激活能基本一致。在600～800℃范围内铁素体内会有阻碍再结晶进程的三次渗碳体析出,从而使再结晶激活能明显提高。高C含量实验钢中还会有从奥氏体转变而来的粗大珠光体或渗碳体,轧制过程中其附近形成的变形区会促进600～800℃加热时该区域附近率先发生再结晶形核、降低再结晶激活能。固溶的Mn、S元素可微弱提高再结晶激活能,但高Mn、S含量会改变粗渗碳体从奥氏体析出时的形态。

Four experimental steels based on grain oriented electrical steel containing C,or Mn and S were prepared.Microstructure evolution of the steels close to a state of equilibrium precipitation were observed during annealing processes at 600-1000 ℃after 60% cold rolling,the changes of recrystallization volume fraction were analyzed statistically as the annealing was prolonged,and the activation energy for static recrystallization of the steels were calculated.The locations,where the recrystallization grains appeared preferentially in the steels with higher C content were observed.It is found that the ferrite in the steels has similar composition and activation energy for static recrystallization at 900-1000 ℃.Tertiary cementite precipitates from the ferrite at 600-800 ℃,which retards the recrystallization and increases the activation energy obviously.Coarse pearlite or cementite in steels with higher C content forms from austenite,around which the deformation zones formed during rolling accelerate recrystallization nucleation and reduce the activation energy during annealing at 600~800 ℃.Solid-solved Mn and S atoms increase slightly the activation energy obviously,and change the morphology of coarse cementite from austenite.