共查询到20条相似文献,搜索用时 90 毫秒
1.
2.
高拉速时连铸结晶器内钢液湍流场及其电磁控制研究 总被引:2,自引:0,他引:2
利用数学模型结合低熔点金属合金模型试验研究全幅二段恒稳磁场控制结晶器内气液两相流场和夹杂物粒子的运动轨迹。结果表明,水口喷吹氩气结合施加恒稳磁场的作用,同时达到控制结晶器内弯月面波动、获得活塞流和抑制后凝固区偏析的目的。氩气喷吹和磁场共同作用既能保持液面稳定又能避免凝结发生。吹入氩气能增加夹杂物的去除率。施加磁场时,夹杂物运动速度明显降低.夹杂物的富集率降低。 相似文献
3.
4.
5.
6.
众所周知,电机是以磁场为媒介进行电能与机械能相互转换的电力机械。磁场可以由电流励磁产生,也可以由永磁体产生。但一般的永磁体,由于磁能密度低,因而所建立的能量交换所必需的气隙磁场强度也较低,所以只能制造容量小的永磁电机,如目前大量生产的铁氧体永磁电机。高性能稀土永磁材料,特别是钕铁硼问世后,情况发生了重大变化。高性能钕铁硼磁体产生的磁场,不仅可以达到电流励磁所产生的磁场要求, 相似文献
7.
文中研究了磁场热处理参数对低钴型Fe-Cr-Co系永磁合金的显微组织及磁性能的影响,探讨了生产上经常发生磁性能不稳定的原因及改进措施。结果表明,精确控制磁场热处理温度是优化调幅分解组织,使低钴型Fe-Cr-Co系合金稳定达到最佳磁性能的关键。较高的磁场强度也是实现热处理优化的重要条件之一。在生产条件下,通过优化热处理工艺收到改善与稳定低钴型Fe-Cr-Co系合金磁性能的良好效果。 相似文献
8.
低、中强度脉冲磁场回火对几种钢的组织和性能的影响 总被引:1,自引:0,他引:1
用自制的低、中强度脉冲磁场(25—100KA/m)热处理设备对高速钢、轴承钢和弹簧钢的回火进行系统研究。发现,高速钢在脉冲磁场中回火可显著加速二次硬化过程,促进残余奥化体转变使回火时间缩短一倍以上。经x射线和电镜分析指出:脉冲磁场回火不仅使马氏体中合金碳化物的析出更加均匀弥散,而且使马氏体的正方度明显升高,从而赋于高速钢更高的硬度和红硬性;轴承钢经脉冲磁场回火可使残余奥氏体量显著减小并使内应力大大降低从而可能取代精密零件的冷处理工艺;弹簧经脉冲磁场热强压处理,可使弹簧的松驰能力和稳定性大大提高,为生产高性能弹簧开辟了新的途径。 相似文献
9.
高能加速器主环磁铁是一种不同于一般常用直流磁铁的磁性材料。它处于慢脉冲励磁下工作,在每一个脉冲周期内粒子束流从注入,加速到引出使磁铁处在一个由弱磁场到强磁场周期变化的磁场下。因此,加速器要求主磁铁材料不但有高的饱和磁感值,低矫顽力而且要求在弱磁场下也有高的导磁率。是我国尚未生产过的一种特殊用途 相似文献
10.
低场下退磁效应对磁制冷材料磁熵变的影响 总被引:1,自引:1,他引:0
磁熵变化值是衡量磁制冷材料好坏的一项重要指标。基于前差商的数值方法,利用温度插值方法分别计算了球体材料和长径比为5的长圆柱体材料的在低场下(2T)扣除退磁场后的实际磁熵变,研究了由材料形状引起的退磁效应对磁制冷材料磁熵变的影响。结果表明,长圆柱体材料的实际磁熵变最接近无退磁场情况下的理论值,而球体材料退磁场很大,其实际磁熵变大大低于理论值;随外场的增强,退磁场对磁熵变的影响逐渐减弱;另外随温度升高退磁场所带来的影响逐渐减弱;若材料本身的磁熵变数值较大,则退磁场的影响相对较小。 相似文献
11.
12.
为了研究退火温度、磁场强度、磁场方向及退火时间等对低牌号无取向硅钢磁性能和组织的影响,在正交试验的基础上,对无取向硅钢进行不同条件的退火处理,通过对磁性能数据的正交分析,优选出最佳的工艺参数。研究结果表明:退火温度和磁场强度是影响试验钢比饱和磁化强度的主要因素,磁场强度与退火时间对剩余磁化强度也有显著的影响。当加热温度在800℃、施加磁场强度为3 T时,调整施加磁场的方向与退火时间可以使无取向硅钢的比饱和磁化强度、比剩余磁化强度分别达到260.7 emu/g、18.265 emu/g。 相似文献
13.
14.
In order to study the effect of alternating magnetic field on the hardness of W6Mo5Cr4V2 high- speed steel cutting tool, the influence of different magnetic field frequency and magnetic time on the hardness of high- speed steel cutting tool was studied by the self- made magnetized experiment platform, using the Origin software to draw a magnetic hysteresis curve of W6Mo5Cr4V2 materials, the magnetization of ferromagnetic materials was further analyzed. The experimental results show that: under the low frequency magnetization condition of the magnetization parameter of 10Hz, the hardness of high speed steel cutting tool improves 4. 58HRC; the rate of hardness change at magnetization time of 30s is 4. 54% higher than that at magnetization time of 120s; alternating magnetic field processing can improve the dispersion carbide content of the tool, reinforce materialistic matrix, improve the hardness of high speed steel tool. 相似文献
15.
16.
17.
18.
针对工频配电网中节能变压器、兆瓦级DC/DC变换器中频隔离变压器、柔性低频交流输电领域低频变压器等电力装备对高性能取向硅钢的应用需求,采用任意波形磁场激励软磁测量系统,研究了0.10~0.27 mm不同牌号取向硅钢在不同工作频率下的电磁特性,探讨了薄规格取向硅钢在中低频电力装备中的应用前景。与0.10 mm超薄取向硅钢相比,0.18 mm高磁感取向硅钢在15~400 Hz中低频率范围具有更低的损耗特征。0.18 mm产品不仅在轧向的铁损低于0.23 mm和0.27 mm产品,在横向也具有最低损耗优势;但对于相同厚度材料,轧向低损耗并不意味着横向同样具有低损耗。分析了不同厚度取向硅钢电磁特性差异及原因,结果可支撑各类型变压器铁心材料选型。结合工频、中频和低频领域电力装备技术发展对铁心材料性能要求,展望了薄规格取向硅钢未来的发展趋势。 相似文献
19.
Utilizing ANSYS CFX commercial software and volume fraction of fluid (VOF) model, fluctuation behav- ior of steel/slag interface was numerically simulated in continuous casting mold with static magnetic field, and the influence of metal jet characteristics on the behavior of steel/slag interface was investigated. The results indicated that the behavior of steel/slag interface is similar at different process parameters, which is closely related to the characteristic of the flow field. The steel/slag interface has an obvious trough characteristic, which can be divided in- to three zones: frontal valley zone, back valley zone and horizontal zone~ as the magnetic flux density increases, the fluctuation of liquid level increases firstly and then decreases, and a reasonable magnetic flux density can make steel/ slag interface obtain a relatively flat interface, which can prevent slag from being entrapped into liquid steel. For a thin slab continuous casting process, when the casting speed is 4 m/min, a reasonable magnetic flux density is about 0.5 T, and the interfacial fluctuation is weaker. No matter the position of magnetic field is horizontal or vertical, for different operating parameters, there is a corresponding reasonable magnetic field position where the steel/slag inter- face fluctuation can be properly controlled and slag entrapment can be prevented. 相似文献
20.
The influence of rotating magnetic field on hardness of 45 steel was studied. The 45 steel which was under the process of laser transformation hardening was magnetized by self- made magnetic enforcement device. The effect of magnetic frequency, magnetic time on hardness of 45 steel was studied. The microstructure of 45 steel laser transformation hardening layer was analyzed by metallographic microscope, and its microscope mechanism of properties?? improvement was considered. Experiment results show that surface hardness values of 45 steel samples are all improved under proper magnetic processing parameters. A part of retained austenite is transformed into martensite because of decrease of martensite activation energy when rotating magnetic field is applied. Dislocation redistributes and becomes more uniform. Microstructure of the sample is more compact. 相似文献