粉末冶金法制备高硅硅钢片的轧制和热处理工艺研究
发布时间：2018-07-31 16:25
【摘要】：硅含量在6.5%左右的高硅硅钢片具有十分优异的磁性能：磁导率高、铁损低、磁致伸缩小,可以实现低能耗、低噪声,是一类节能环保的软磁材料。但是6.5%硅钢是一种脆性材料,不可轧制加工,因此不能用传统轧制的工艺来制备。目前只有日本采用CVD法实现了工业化生产,但其成本高昂。近十几年来,由于粉末冶金法成本低,成为人们制备高硅硅钢片的又一途径。 本文采用不同粉体原料,分别采用粉末轧制法和块体轧制法,探索了用粉末冶金法制备高硅硅钢片的工艺条件,研究了影响轧制工艺和硅钢磁性能的因素,得出了比较适宜的制备工艺,制得了性能较好的高硅硅钢片。 首先,以铁粉为对象,采用有限元法对粉体轧制过程进行了模拟和实验。模拟和实验结果表明,采用粉体轧制时,上下表面由于受力情况与内部不同,多呈现疏松的结构。粉体轧制时,粉体的流动性和辊缝是影响轧制带材的重要因素。辊缝是影响带材密度的主要因素,高流动性的粉体轧制得到的带材较为致密。当原料中存在流动性差的另一硅相时,流动性差的硅相易损失,使带材元素含量偏离配比。 纯铁在1400℃以下时难以烧结致密化。铁硅之间的扩散反应与粉体粒度和温度密切相关,从而影响烧结体的轧制能力,最终影响硅钢的性能。当硅粉粒度适当时,经初次热处理后,得到既无单质Si,又具有较好变形能力时,经二次轧制和高温热处理可以得到密度较高、性能较好的硅钢片。 加入少量的Sn可以提高Si与Fe的反应能力,从而在低温短时间内实现Si与Fe的反应。Sn的加入还可改善Fe的烧结,容易得到大晶粒的Fe。含H2的气氛对烧结硅钢不利,易造成硅的氧化。比较适宜的烧结气氛为Ar。 采用超细硅粉和铁粉混合后,经500-1000℃SPS处理后得到的块体材料具有变形能力,可以通过轧制得到厚度为0.3-0.4mmm的片材,但是经高温热处理得到的硅钢片材氧化严重,带材致密度不高,材料的磁性能比粉末轧制法制备的材料差。 以Fe和FeSi为原料经SPS烧结可制备出具有轧制能力的硅钢锭。FeSi原料的颗粒粒度、SPS温度、压力对Fe和FeSi颗粒之间的扩散反应有影响,从而影响最终产物的物相显微结构。由粗颗粒原料烧结的块体具有良好的延展性,表现为韧性断裂；随粒度的减小、烧结温度的升高,烧结试样延展性变差,逐渐变成脆性断裂。制备致密且具有良好延展性的硅钢锭的适宜工艺条件为：粗FeSi颗粒在1100℃以下温度烧结、烧结压力50MPa。 以具有可轧能力且密度高的硅钢块体为原料,经轧制减薄和退火处理,可以制备出性能较好的高硅硅钢片。其磁性能为饱和磁化强度17740Gs,矫顽力3.670e。其饱和磁化强度与由Fe和Si混合后再轧制烧结制备的硅钢相当,但矫顽力约降低9倍。
[Abstract]:High silicon steel sheet with about 6.5% silicon content has excellent magnetic properties, such as high permeability, low iron loss, low magnetostriction, low energy consumption and low noise, so it is a kind of soft magnetic material which can save energy and protect environment. However, 6.5% silicon steel is a brittle material and cannot be rolled, so it can not be prepared by traditional rolling technology. At present, only Japan uses CVD method to realize industrial production, but its cost is high. In recent years, powder metallurgy has become another way to fabricate high silicon steel due to its low cost. In this paper, using different powder raw materials, powder rolling method and bulk rolling method, the technological conditions of preparing high silicon steel sheet by powder metallurgy method are explored, and the factors influencing the rolling process and magnetic properties of silicon steel are studied. The more suitable preparation process was obtained and the high silicon steel sheet with better performance was prepared. Firstly, the rolling process of iron powder was simulated and tested by finite element method. The simulation and experimental results show that when the powder is rolled, the upper and lower surfaces show loose structure due to the difference between the internal and the loading conditions. The fluidity of powder and the roll gap are the important factors affecting the rolling strip. Roll gap is the main factor affecting strip density, and the strip produced by high fluidity powder rolling is compact. When there is another silicon phase with poor fluidity in the raw material, the silicon phase with poor fluidity is easy to lose, which makes the element content of strip deviate from the ratio. It is difficult to densify pure iron when it is below 1400 鈩，
本文编号：2156141
[Abstract]:High silicon steel sheet with about 6.5% silicon content has excellent magnetic properties, such as high permeability, low iron loss, low magnetostriction, low energy consumption and low noise, so it is a kind of soft magnetic material which can save energy and protect environment. However, 6.5% silicon steel is a brittle material and cannot be rolled, so it can not be prepared by traditional rolling technology. At present, only Japan uses CVD method to realize industrial production, but its cost is high. In recent years, powder metallurgy has become another way to fabricate high silicon steel due to its low cost. In this paper, using different powder raw materials, powder rolling method and bulk rolling method, the technological conditions of preparing high silicon steel sheet by powder metallurgy method are explored, and the factors influencing the rolling process and magnetic properties of silicon steel are studied. The more suitable preparation process was obtained and the high silicon steel sheet with better performance was prepared. Firstly, the rolling process of iron powder was simulated and tested by finite element method. The simulation and experimental results show that when the powder is rolled, the upper and lower surfaces show loose structure due to the difference between the internal and the loading conditions. The fluidity of powder and the roll gap are the important factors affecting the rolling strip. Roll gap is the main factor affecting strip density, and the strip produced by high fluidity powder rolling is compact. When there is another silicon phase with poor fluidity in the raw material, the silicon phase with poor fluidity is easy to lose, which makes the element content of strip deviate from the ratio. It is difficult to densify pure iron when it is below 1400 鈩，
本文编号：2156141
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