成品厚度对高牌号无取向电工钢组织、织构和磁性能的影响

文中采用某企业高牌号无取向电工钢常化板,经过不同冷轧压下率一次性冷轧后高温退火,获得了不同厚度的成品板。利用EBSD等手段研究了成品厚度对组织、织构和磁性能的影响。研究结果表明,随着成品厚度减薄,总铁损不断降低,尤其在高频下降低更为明显,这是因为高频下涡流损耗占主导,同时涡流损耗占总铁损的比重也随着成品厚度减薄而不断降低。平均晶粒尺寸随着成品厚度减薄略有减小,组织均匀性变差,但厚度减薄导致的涡流损耗降低仍占据着主导作用,因此总的铁芯损耗出现下降。随着冷轧压下率的增加,γ织构和α*织构不断增强,λ织构呈减弱的趋势;有利织构与有害织构体积分数的比值不断下降,导致磁感应强度B50也随之降低。

Effect of final thickness on the microstructure,texture and magnetic properties of high-grade non-oriented electrical steel sheets

The high-grade non-oriented electrical steel normalized sheets from an enterprise was cold rolled with different cold rolling reduction ratios and annealed at high temperature to obtain final sheets at different thicknesses. Final thickness on microstructure, texture and magnetic properties were studied by means of EBSD. The results showed that the total iron losses continued decreasing as the thickness of final sheets decreased, especially at high frequencies, the underlying reason of which was that eddy current losses dominated at high frequencies, and at the same time its proportion to total iron losses decreased continuously as the thickness of final sheets decreased. The average grain size decreased slightly and the microstructure uniformity deteriorated with the thickness reduction of final sheets. Given that the reduction of eddy current losses caused by thickness reduction still dominated, the total iron losses decreased. With the increase of cold rolling reduction ratio, the γ texture and α* texture were continuously enhanced while the λ texture was weakened. The volume fraction ratio of the favorable texture to the harmful texture continued declining, leading to the decrease of magnetic flux density B₅₀.