无取向电工钢脱碳组织的动力学分析

无取向电工钢两相区脱碳退火获得柱状铁素体晶粒可有效改善材料组织的均匀性.本文从动力学角度分析柱状晶的生长过程.柱状晶的形成分为“形核”和定向生长两个阶段,其中定向生长过程本质上是反应扩散和再结晶长大共同引起的界面迁移,且在动力学上符合抛物线规律,但其生长速率与退火温度之间并非呈单调的变化关系,而是在900℃时呈极大值.最后结合柱状晶生长速率的导出公式得到柱状晶“晶核”的尺寸约束条件,这对实际生产过程中无取向电工钢脱碳工艺的设计有一定的指导意义.

Kinetic analysis of decarburized microstructure in non-oriented electrical steel

Decarburization of non-oriented electrical steel in the two-phase region is a known method to acquire a columnar ferrite structure which may effectively ameliorate the microstructure homogeneity of materials.In this paper,the growth process of columnar grains was analyzed from the kinetics point of view.The results show that the columnar structure formation involves two stages:nucleation and directed growth.Directed growth is a sort of interface migration process caused by both reaction-diffusion and recrystallization growth,and fits a parabolic law.The growth rate and the annealing temperature do not show a monotonic functional relationship,but the growth rate reaches a maximal value when the temperature is 900 ℃.At last,we get the size constraint condition of columnar nuclei on the basis of the derived growth rate formula,which may present some significance for guiding the design of relevant decarburization parameters in industrial production.