Table of Content

28 October 2019, Volume 1 Issue 1

  

Discussion on the strategic development of electrical steel industry from the perspective of energy development in China

ZHANG Shourong, CHEN Zhuo, HU Shoutian

2019, 1(1):  1-4. 

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Electric energy is a significant support for the economic construction and people's life of a country, and it is also the basis for the development of electrical steel industry. Focusing on energy development, future electricity demand and structural changes, this paper analyzes and looks forward to the growth of high－end electrical steel demand, the development process of China's electrical steel industry and future strategic ideas.

Research on the production process and the demand of the extremely thin oriented electrical steel

CHEN Zhuo

2019, 1(1):  5-7. 

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This paper focuses on a kind of extremely thin oriented electrical steel with high frequency, whose thickness is 0.10 mm(0.08 mm), 0.05 mm, 0.03 mm, width is below 350 mm, and the frequency is between 400 and 3000 Hz. The product is mainly imported. In recent years, some enterprises have developed a kind of raw material of HiB oriented electrical steel without the glass film, and put it into use, which achieved obvious effect. The research shows that the appearance of the raw material of HiB oriented electrical steel without glass film changes the previous production process, mainly solves the problem of "bottle-neck" of removing surface coating and bottom layer of glass film, and reduces a working procedure. It lays an important foundation for stable production of extremely thin oriented electrical steel to realize localization and reduce import.

Preparation and characterization of oriented high silicon steel

LIU Gang, TANG Baijin, LIU Xinli, LEI ming, ZHEN Xiaofeng

2019, 1(1):  8-10. 

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The structure, phase, texture and magnetic properties of the samples of the finished grain oriented silicon steel with Si content of 3% were tested and analyzed after solid siliconizing and diffusion annealing by pack cementation. The results showed that: the silicon permeable layer with smooth surface, dense interior and good bonding with matrix can be prepared on the oriented silicon steel with Si content of 3 % in a short time (10 min) under the condition of 800 ℃ and silicon powder + (mass fraction 0.5 %) halide + filler, and Goss texture can be completely retained with high frequency iron loss reduced significantly (37 %~63 %) after diffusion annealing. It has been proved that solid silicon osmosis technology can prepare oriented high silicon steel with excellent magnetic properties.

Effect of temperature field of high temperature ring furnaceon magnetic properties of grain oriented silicon steel

HU Shoutian, XIA Tian, SHEN Xinyi, ZHOU Yujun, LUO Zhonghan

2019, 1(1):  11-15. 

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The temperature distribution of grain oriented silicon steel coil in ring furnace was analyzed by the model of temperature field in ring furnace. The influence on silicon steel’s property from the temperature field was discussed. The result showed that，there was an obvious temperature difference at different positions of the steel coil during heating stage, which affects the secondary recrystallization process of the oriented silicon steel, and then leads to the difference of the magnetic properties of the oriented silicon steel.

Measurement and analysis of nonuniformity of iron lossdistribution in oriented electrical steel strip

LI Xiuzhang, ZHOU Xinhua

2019, 1(1):  16-18. 

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At present, more and more attention has been paid on the uniformity of transverse iron loss distribution of oriented electrical steels. The magnetic performance testing methods are mainly divided into static and dynamic testing(online detection). Now, there is no relevant testing method for dynamic testing of electrical iron loss performance in China. In this paper, we studied on the method and reliability of dynamic measurement of iron loss transverse distribution of electrical steel strip in online measurement by the method of using a small single permeameter to measure iron loss in different regions of large single steel sheet sample on the basis of GB/T 13789—2008. The results showed that there is good correlation and consistency between the iron loss distribution in different areas measured by permeameter close to the sample and permeameter separating 10 mm from the sample.

Influence of magnetostriction of grain oriented silicon steel on magnetic domain structure

ZHU Yechao, TIAN Wenzhou, LUO Zhonghan, HU Shoutian, SUN Liang, GUO Xiaolong, CHEN Xiangwei

2019, 1(1):  19-22. 

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It was summarized in this paper the factors which influence the magnetostriction of grain oriented silicon steel. The AcDc magnetic properties measurement device, magnetostriction measurement device and magnetic domain viewer were used to investigate the influence of permeability and domain structure on the magnetostriction of grain oriented silicon steel. It was found that the domain deviation angle has direct influence to the maximum negative magnetostriction; the wedgelike domain has great influence on the saturated magnetostriction；the wedgelike domain can be reduced by laser scribing and thus magnetostriction can be decreased.

Effect of Bi on microstructure and texture during high temperature annealing of low temperature grainoriented silicon steel

SHEN Minghui, YANG Jiaxin, GUO Xiaolong, LUO Xingen, GAO Yang, CHENG Xiangwei

2019, 1(1):  23-28. 

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The annealing processes of low temperature grainoriented silicon steel which containing bismuth（Bi）and Bifree components have been studied by interrupting test，and the magnetic properties were measured by magnetic determinator (MPG200D), the evolution of texture and grain size was analyzed by Xray diffraction (XRD) and optical microscopy. The results showed that the primary grain size decreased and the secondary recrystallized grain size increased to 20~60 mm after the addition of Bi element. The onset temperature of secondary recrystallization was increased significantly after the addition of Bi element,and the temperature ranges of grain abnormal growth on containing Bi and Bifree sample were 1 080~1 100 ℃ and 1 060~1 080 ℃ respectively. The texture analysis showed that as the high temperature annealing temperature increased, the {111} and {100} textures were gradually weakened, the {110} texture and Goss texture were gradually enhanced. The texture transformation temperatures of containing Bi and Bifree samples were 1 100 ℃ and 1 080 ℃ respectively, then the Goss texture density and volume fraction increased gradually. The Goss texture density and volume fraction of Bicontaining samples were higher than those of Bifree samples.

Effects of normalizing treatment on microstructure, texture and magnetic properties of 50W800 electrical steel

WU Xiaolong, YANG Ping, GU Xinfu, PEI Wei, LENG Yemin

2019, 1(1):  29-36. 

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Effects of normalizing temperatures on the microstructure, texture and magnetic properties of the 50W800 hot rolled sheets were investigated by optical microscopy and EBSD technique. The results showed that the grains in surface regions are coarsened significantly after normalization, and the grain sizes can reach more than 500 μm. Normalization can increase the magnetic induction B50 by 0.041 T and reduce the iron loss P1.5/50 by 0.6 W/kg. Compared with the final sheets without normalizing treatment, the {111} texture ratio of the normalized final sheets decreased, the Goss texture ratio slightly increased, and the magnetic induction increased. There is no direct relationship between the grain sizes of the final sheets and the initial grain sizes of the normalized sheet. The larger the initial grain size is, the stronger the nucleation at shear bands in deformed sheets, and the smaller the recrystallized grain sizes after recrystallization. It is noted that the non{111} oriented grain grows faster than the {111} oriented one during further annealing, therefore, prolonging the holding time can effectively improve magnetic properties.

Comparison of inclusions and precipitates in different grade nonoriented electrical steels

REN Qiang, CHENG Lin, HU Zhiyuan, ZHANG Lifeng

2019, 1(1):  37-41. 

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In the current study, automatic scanning electron microscope and field emission scanning electron microscope were employed to analyze types and morphologies of inclusions and precipitates in nonoriented electrical steels. A thermodynamic software FactSage was conducted to analyze the inclusion formation behavior. With the increase of aluminum content, oxide inclusions changed with the the sequence of SiO2-Al2O3-MnO→Al2O3→MgO·Al2O3. For Aldeoxidized nonoriented electrical steels, angular AlN was the dominative nitride. Besides, the relationship between the average size of AlN and Al content was {d}μm=3.75·[%Al]-0.57. The content of Mg increased with the increasing Al content. With the increase of magnesium content and the decrease of sulfur, sulfides changed with the sequence of (Mn,Cu)S→(Mn,Mg)S→MgS.

Effect of annealing temperature on microstructure and magnetic properties of nonoriented silicon steel containing 2.5 %Si

HE Zhijian, SHI Lifa, PEI Yinghao, CHENG Guoqing, ZHAN Yungao, XIA Xuelan

2019, 1(1):  42-48. 

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The effect of annealing temperature on microstructure and magnetic properties of nonoriented silicon steel containing 2.5 %Si was investigated in this paper. The results showed that, the effect of annealing temperature on magnetic properties is obvious, with the increase of annealing temperature from 850 ℃ to 1 050 ℃, the iron loss P1.5/50 value is firstly decreased and then increases slightly, and reaches the lowest at 950 ℃, P1.0/400 value is firstly decreased and then increased, and reaches the lowest at 900 ℃. With the increase of annealing temperature, the strength of beneficial texture components decreases gradually, and the magnetic induction B50 decreases monotonously.

Application problems of national standards of measuring methods for alternatingcurrent magnetic properties of electrical steel and their solutions

SHEN Jie, TANG Ling, ZHOU Xing

2019, 1(1):  48-54. 

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This paper groomed and analyzed the problems of current national standards of measuring methods for alternatingcurrent magnetic properties of electrical steel（including Epstein frame and single sheet test）, such as, correcting specific core loss while waveform distorted, assumed effective magnetic path length is not the true one, and lack of calibration method of magnetic test system. And some solutions were also proposed like using digital feeback control technology to avoid correcting specific core loss, assuming effective magnetic path length as 475mm, and comprehensive calibration method for magnetic test system.

Typical faults of silicon steel acid regenerated graphite heat exchanger and its improvement measures

2019, 1(1):  55-58. 

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The graphite heat exchanger in the predesilication area of Shougang siliconsteel acid regeneration unit is a blockhole type graphite heat exchanger, which is used to cool the waste acid transported from the pickling line of silicon steel. The content of Silicon mud in the waste acid discharged from the pickling line to the predesilication unit is about 500 mg/L. Since putting into production, the silicon mud blockage of graphite heat exchanger in predesilication area often occurs. In this paper, the structure of the graphite heat exchanger, the typical faults and the existing problems of the current treatment methods were discussed in detail, and the improvement measures were put forward. Through the reasonable selection and optimization of equipment, an online alkaline cleaning system is set up, and the reaction between SiO2 and NaOH is used to generate Na2SiO3 which is soluble in water. Therefore, it is convenient and effective to dredge the graphite heat exchanger online, which improves the input rate of the graphite heat exchanger and greatly reduces the cost of maintenance and spare parts.