Effect of non-metallic precipitates and grain size on core loss of non-oriented electrical silicon steels

• Published in: Journal of magnetism and magnetic materials 2018-04, Vol.451, p.454-462
• Main Authors: Wang, Jiayi, Ren, Qiang, Luo, Yan, Zhang, Lifeng
• Format: Article
• Language: English
• Subjects: Aluminum nitride; Chemical precipitation; Core loss; Density; Grain size; Metal sheets; Non-oriented electrical silicon steel; Precipitates; Regression analysis; Silicon; Silicon steels; Steel
• ISSN: 0304-8853; 1873-4766
• DOI: 10.1016/j.jmmm.2017.11.072

•The effects of larger inclusions on the core loss are studied.•Hypothesis ideal model of eddy current loss, as well as hysterisis loss, and grains is proposed.•A simple calculation model of core loss is proposed which need to be refined. In the current study, the number density and size of non-metallic precipitates and the size of grains on the core loss of the 50W800 non-oriented electrical silicon steel sheets were investigated. The number density and size of precipitates and grains were statistically analyzed using an automatic scanning electron microscope (ASPEX) and an optical microscope. Hypothesis models were established to reveal the physical feature for the function of grain size and precipitates on the core loss of the steel. Most precipitates in the steel were AlN particles smaller than 1 μm so that were detrimental to the core loss of the steel. These finer AlN particles distributed on the surface of the steel sheet. The relationship between the number density of precipitates (x in number/mm2 steel area) and the core loss (P1.5/50 in W/kg) was regressed as P1.5/50 = 4.150 + 0.002 x. The average grain size was approximately 25–35 μm. The relationship between the core loss and grain size (d in μm) was P1.5/50 = 3.851 + 20.001 d−1 + 60.000 d−2.