轧制法制备低铁损高磁感高硅钢及其涂层研究

发布时间：2018-08-23 15:42

【摘要】：高硅电工钢具有高磁导率、高电阻率、低铁损和几乎为零的磁致伸缩系数等优异的软磁性能,在节约能源、降低设备噪音等领域具有广泛的应用前景。开发高磁感低铁损高硅钢薄板及其绝缘涂层制备技术具有很高的工业应用价值。本文通过织构优化和对晶粒尺寸及有序度控制,制备出沿轧制方向上具有高磁感低铁损的新型无取向高硅钢,另外采用低温渗氮追加抑制剂的方法制备出磁感更高的取向高硅钢,为优化高硅钢薄板磁性能提供了方法和思路。研究了晶粒尺寸与织构对磁性能的影响,建立了磁滞损耗常数随晶粒尺寸与各向异性参数变化的数学模型,为织构优化降低铁损提供理论指导。针对高硅钢容易表面氧化和冲片性更差等特点,开发了一种高硅钢用环保半有机绝缘涂层及表面预处理方法,给工业应用提供参考。为得到达标的冲片性能,对高硅钢冷轧及退火薄板进行冲片实验,研究了冲片断裂行为、断口组织特征及有序度差异对冲片性能的影响具有理论价值。主要结论如下：(1)通过采用大压下率热轧,确保次表层中产生更多的η织构(以高斯织构为主)随后进行遗传；温轧板中粗大的晶粒有利于冷轧剪切带的形成；冷轧板退火后生成强{210}001织构及次表层部分高斯织构是在轧向上获得高磁感的原因,归结于{210}001和高斯取向晶粒在{111}112冷轧形变晶粒内的剪切带优先形核并长大；冷轧退火板经过长时间高温退火后,以{310}001织构为代表的η织构得以保留并且增强,进一步提高了磁感。(2)高硅钢冷轧退火薄板磁感B8值的高低与F织构取向晶粒的比重密切相关,而B50值与γ织构和λ织构取向晶粒的比重有关。高硅钢的磁滞损耗可以通过增大晶粒尺寸和优化织构得以大幅度降低。织构对铁损的影响虽随着频率的升高逐渐减小,但对高频铁损的影响不可忽略。随着退火温度的升高和时间的延长,高硅钢铁损在轧向和横向上的显著差异保持到更高的频率下,归因于晶粒尺寸的增大、γ织构的减弱和较强的η织构的保留。织构与晶粒尺寸共同影响高硅钢的高频铁损。(3)采用轧制结合低温渗氮工艺制备的取向高硅钢的磁感B8与B50值要高于具有强η织构的新型无取向高硅钢。随着渗氮后氮含量的增加,高硅钢薄板二次再结晶发展更加完善,二次再结晶晶粒尺寸增大的同时,高斯织构锋锐度也不断增强,磁感不断提高。这是因为除了高斯取向晶粒之外,次表层中较多的{110}116取向晶粒也具有大量的20-45。高能晶界,当抑制剂数量少、受到抑制力较弱时,容易优先异常长大,以{110}低表面能与高斯取向晶粒竞争吞并周边其他取向的小晶粒。提高渗氮量可以增加抑制剂浓度,抑制部分偏高斯取向晶粒的异常长大,从而提高高斯织构锋锐度。(4)高硅钢在脱碳退火过程中表面生成的氧化膜主要成分有Si02和Fe2SiO4,以及少量的FeO,相对于普通3%Si硅钢,在相同的脱碳退火工艺条件下,表面生成更多的SiO2。在涂覆绝缘涂层之前有必要对高硅钢退火板进行表面预处理,减少表面氧化膜厚度,提高绝缘涂层的附着性。在涂覆量不变的情况下,高硅钢表面越清洁、越平整,氧化膜越薄,涂层的附着性越好。本文制备的环保半有机绝缘涂层每面涂覆量控制在0.8-1.2 g/m2,附着性、冲片性及绝缘性能良好,层间电阻保持在5 Ω.cm2/片以上。(5)0.2-0.3mm厚的高硅钢冷轧薄板在冲片间隙为0.01mm、冲片温度为100℃的条件下具有良好的冲片性能,晶粒细小的退火板比晶粒粗大的退火板冲片性更好。高硅钢退火板在低温下冲片发生脆性断裂的解理面主要为{100}晶面,解理系统包括{100}110和{100}100,靠其一或两者交替开动完成断裂。高硅钢薄板冲片性能的好坏主要与冲片温度、有序化程度及晶粒尺寸有关。降低有序化程度、提高冲片温度及细化晶粒,可以改善高硅钢薄板韧塑性,提高其冲片性能。综合考虑冲片性能和工业成本,高硅钢冷轧薄板最好在退火前冲片。
[Abstract]:High silicon electrical steel has excellent soft magnetic properties such as high permeability, high resistivity, low iron loss and almost zero magnetostrictive coefficient, which have wide application prospects in the fields of energy saving and noise reduction. A new type of non-oriented high silicon steel with high magnetic induction and low iron loss along the rolling direction was prepared by texture Optimization and grain size and order control, and a high magnetic induction oriented high silicon steel with higher magnetic induction was prepared by adding inhibitors at low temperature nitriding, which provides a method and idea for optimizing the magnetic properties of high silicon steel sheets. Mathematical model of hysteresis loss constant varying with grain size and anisotropic parameters was established to provide theoretical guidance for texture Optimization and reduction of iron loss.A kind of environmental-friendly semi-organic insulating coating and surface pretreatment for high-silicon steel were developed in view of the characteristics of easy surface oxidation and worse punching property of high-silicon steel. In order to obtain the standard sheet properties, the cold rolled and annealed high silicon steel sheets were punched. The fracture behavior, fracture morphology and the effect of ordering on the properties of the sheets were studied. The main conclusions are as follows: (1) High reduction hot rolling was used to ensure the sub-surface layer. More_texture (mainly Gaussian texture) is produced and inherited subsequently; coarse grains in warm rolled sheets are favorable for the formation of cold rolled shear bands; the formation of strong {210} 001 texture and sub-surface part of Gaussian texture after annealing of cold rolled sheets is the reason for obtaining high magnetic induction upward, which is attributed to {210} 001 and Gaussian orientation grains in {111} 112 cold rolled form. The_texture represented by {310} 001 texture can be retained and strengthened after a long time of high temperature annealing, which further improves the magnetic induction. (2) The magnetic induction B8 value of cold rolled annealed sheet of high silicon steel is closely related to the proportion of F texture oriented grains, while the B50 value is related to the gamma texture and texture. The hysteresis loss of high silicon steel can be greatly reduced by increasing grain size and optimizing texture. Although the effect of texture on iron loss decreases gradually with the increase of frequency, the effect on high frequency iron loss can not be ignored. The significant transverse difference is maintained at higher frequencies due to the increase of grain size, the weakening of gamma texture and the retention of strong_texture. Texture and grain size together affect the high frequency iron loss of high silicon steel. (3) The magnetic susceptibility B8 and B50 values of oriented high silicon steel prepared by rolling combined with low temperature nitriding process are higher than those of oriented high silicon steel with strong_texture. With the increase of nitrogen content after nitriding, the secondary recrystallization of high silicon steel sheet develops more perfectly, the grain size of secondary recrystallization increases, and the Gauss texture sharpness and magnetic induction increase. This is because there are more {110} 116 oriented grains in the subsurface besides the Gauss oriented grains. It also has a large number of 20-45. High energy grain boundaries, when the number of inhibitors is small and the inhibitory force is weak, it is easy to preferentially grow abnormally. Low surface energy of {110} can compete with the Gaussian oriented grains to engulf small grains with other orientations around. Increasing nitriding amount can increase the inhibitor concentration, inhibit the abnormal growth of some grains with biased Gaussian orientation, and thus increase them. Gauss texture sharpness. (4) Si02 and Fe2SiO4 are the main components of the oxide film formed on the surface of high silicon steel during decarbonization annealing, and a small amount of FeO. Compared with the ordinary 3% Si steel, the surface of high silicon steel annealed by the same decarbonization annealing process produces more SiO2. It is necessary to pre-place the surface of high silicon steel annealed sheet before coating. The surface of high silicon steel is cleaner, smoother, and the oxide film is thinner, and the adhesion of the coating is better. The semi-organic insulating coating prepared in this paper is controlled at 0.8-1.2 g/m2 per side, with good adhesion, punching and insulation, and interlayer electricity. (5) 0.2-0.3 mm thick cold rolled sheet of high silicon steel has good sheeting properties under the condition of blanking gap 0.01 mm and blanking temperature 100 C. The sheet with fine grain is better than that of annealed sheet with coarse grain. The cleavage system consists of {100} 110 and {100} 100. The fracture of high silicon steel sheets is completed by one or both of them start alternately. The properties of high silicon steel sheets are mainly related to the temperature, degree of ordering and grain size of the sheets. Yes, considering the flush performance and the industrial cost comprehensively, the high silicon steel cold rolled sheet should be flush before annealing.
【学位授予单位】：北京科技大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TG335;TG174.4

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