升温速率对低碳无取向电工钢脱碳退火组织及织构的影响

INFLUENCE OF HEATING RATE ON THE DECARBURIZED ANNEALING MICROSTRUCTURE AND TEXTURE IN LOW-CARBON NON-ORIENTED ELECTRICAL STEEL

研究了不同升温速率下低碳电工钢两相区脱碳退火组织与织构的演变规律.结果表明,脱碳退火升温速率对最终组织和织构均有显著影响:升温速率决定了柱状晶的"形核"位置,慢速升温时,柱状晶"晶核"在表层向里的一定范围内形成,最终在样品表面附近形成小尺寸晶粒层,而快速升温则形成完整的柱状晶组织;慢速升温时获得强g线织构及相对较弱的a线织构,而快速升温则使g线织构大幅度减弱,a线组分有所增强,并产生了一定强度的{001}<120>织构.实验结果证明,最终的脱碳退火织构主要取决于"形核"处再结晶晶粒的织构成分.

The present work investigates the effect of heating rate on the evolution of decarburized microstructures and textures in low-carbon electrical steels within the inter-critical temperature region.The results show that heating rate has a significant effect on both the final microstructures and textures during the process of decarburization annealing.The ’’nucleation’’ sites of columnar grains are determined by the heating rate.Slow heating rate would have the ’ nuclei’’ formed within a certain range of the surface layer,and finally leading to a fine-grained layer near the sample surface.By comparison,a complete columnar microstructure is acquired under the rapid heating condition.Strong g-fiber and relatively weak a-fiber components were obtained at the slow heating rate.In contrast,g-fiber texture is greatly weakened and a-fiber component slightly strengthened under the rapid heating condition,and a relatively strong {001}〈120〉 texture is formed at the same time.The experimental results prove that the final decarburized textures are mainly dependent upon the texture component of recrystallized grains in the ’’nucleation’’ sites.