修理异步电动机以铜线代替铝线后如何计算?

我国以往计划经济时代，曾经大量生产铝线电动机，这是当时铜资源紧张而不得不采取的手段。但铝线焊接困难，并且铝线规格不配套，造成维修困难，为此多数都换用铜线来代替。修理的原则是保持功率不变，保持原有匝数不变，同时保持电阻不变。由于铜的电阻系数是铝的0．627倍，一般只要查出原铝线的截面积后乘以O．627倍，其商就是铜线的截面积，再查铜线表查知铜线的直径。简单的办法是把错线的直径直接除以1．26即行c经验告诉我们，直接把铝线直径打个8折（即乘以0．幻即得铜线的直径。这是最便捷的计算方法。求导线截面积的公式：“旷”…     

回复、再结晶中间退火对纯铝导体性能的影响

提高架空输电线路用硬铝线的电导率,开发节能导线为国家电网公司所倡导。通过对硬铝线进行不同温度下的中间退火,研究了回复、再结晶对硬铝线性能的影响。实验结果表明对硬铝线进行180℃回复处理,可在保持硬铝线强度的前提下使其电导率提高0.5%IACS,对硬铝线进行300℃再结晶中间退火可使硬铝线的电导率提高1.5%IACS,但使硬铝线的强度降至140 MPa。再结晶退火过程中过饱和固溶Fe的脱溶析出是导致硬铝线导电率提高的主要原因。     

电致热处理工业纯铝线的强度演化规律

分别采用干燥箱和施加电流装置对工业纯铝线进行了传统的退火处理和电致热处理，并研究了不同温度下退火处理和电致热处理对工业纯铝线强度和微观组织的影响规律及机制。结果表明，当热处理温度相同时，与退火态工业纯铝线相比，电致热处理态工业纯铝线的抗拉强度更低，晶粒尺寸更大，施加电流在工业纯铝线内晶界处导致的局部焦耳热温升是电致热处理态工业纯铝线晶粒尺寸更大的主要机制，也是导致电致热处理态工业纯铝线强度更低的本质。     

铝线

一、绪言从铝线的用途来看,制品本身要求长尺寸的有铝线、围栏用线、筛子网用线等;供设备、装置用的坯料要求长尺寸的有电焊条、电容器导线、冷锻用坯料等.对铝电线及结构材料、部件用铝线的种类、特性、制造方法、需要动向等问题介绍如下.     

铝—铜过渡接头的钎焊

钎料的化学成分、性能和经济性化学成分(%)锡54.94、锌38.41、铝2.62、银2.22。钎料的金相组织属于共晶型钎料。机械性能抗拉强度为10.55公斤/毫米~2;延伸率为12.5%。经济性比较铝—铜钎料每公斤价格为7.32元,焊锡每公斤7元。钎焊工艺焊前准备铜线用硝酸除去氧化膜,用铬酸水溶液处理,用清水冲洗,晾干。铝线放于40～50℃的 NaOH(10%)水溶液中进行清洗,清洗时间为10～20秒,然后用温水冲洗,晾干即可。电机中常用的是氧化膜铝线和聚脂漆包铝线,对于氧化膜铝线可用上述方法清理;对于聚脂漆包铝线,建议用刮刀清理。钎焊过程钎焊所用热源是氧—乙炔焰,钎焊温度是320～350℃,钎焊间隙要适宜,过程如下:     

架空输电用老化态铝及铝合金线屈服强度预测

以退火态架空输电用工业纯铝线和铝镁硅合金线为研究对象,主要研究老化态铝及铝合金线屈服强度预测的方法。研究结果表明:指数函数的基本形式可以较好地描述工业纯铝线和铝镁硅合金线屈服强度与退火时间的关系,通过数值拟合的方法,本文作者提出了老化态工业纯铝线和铝镁硅合金线屈服强度预测公式,基于拉拔态铝线的屈服强度、退火态铝线的稳定屈服强度,老化速率和退火时间便可以计算出退火态铝线的屈服强度;其中,稳定屈服强度和老化速率与温度密切相关,铝线的稳定屈服强度随着退火温度的升高逐渐下降,老化速率则随着退火温度的升高而增大,老化速率越大,老化态铝线屈服强度下降越快。     

架空输电用高电导率铝线研究

分析了20种架空输电导线用硬态铝线的元素组成以及各种杂质元素含量与硬态铝线电导率之间的关系。结果表明,杂质元素总量与电导率并不完全呈负线性关系,微量杂质元素Ti、V、Mn和Cr对其电导率有显著影响,稀土元素对高电导率铝线并无直接影响,适量B元素可有效改善铝线电导率。在杂质元素总量低于0.20%时,仅当w(Ti+V+Mn+Cr)<0.001%、w(Fe)<0.10%,w(Si)<0.05%时,才可使硬态铝线的电导率高于36.25MS/m,同时才可保证其对应软态铝线电导率达到37.12MS/m以上。     

纯铝线强度和导电率反常制约现象及机制分析

在金属成形过程中,其强度和导电率通常呈现出明显的制约关系。然而,在工业纯铝拉丝加工过程中,不同道次的工业纯铝线的强度和导电率却呈现出了反常制约关系。通过对不同道次的工业纯铝线的强度和导电率的测试以及微观组织表征,揭示了工业纯铝线在拉丝成形加工过程中的反常制约机制。结果表明,晶粒在径向的细化以及在轴向的拉长有利于提高纯铝线的强度,同时也有利于改善其导电率;在拉丝过程中产生的111丝织构对强度有贡献且不影响导电率。因此,不同道次的工业纯铝线的强度和导电率实现了同步提升。这一研究成果对钢芯铝绞线用工业纯铝线的生产具有指导意义。     

铜铝线爆破压接试验成功

大吉山钨矿四营三连电工班,遵照伟大领袖毛主席关于“人类总得不断地总结经验,有所发现,有所发明,有所创造,有所前进”的教导,在总结铝线的爆破压接经验的基础上,大胆地进行了铝线与铜线的爆破压接,实践证明是可行的,为铝线的广泛使用创造了有利条件。铜铝线爆破压接工艺大致如下:1.将铜线的被压接部分均匀镀上焊锡,以免铜铝直接接触而发生腐蚀;2.用0.5毫米左右的厚纸,按一定尺     

08A1深冲钢脱氧合金工艺优化研究

唐山建龙在转炉冶炼08A1钢生产过程中,应用中碳锰铁、铝线的合金脱氧方法替代了以往的锰芯铝铁预脱氧与铝线微调的脱氧合金化工艺试验,经过过程跟踪与检验结果表明:08A1钢用中碳锰铁与铝线进行脱氧合金化,钢水质量得到明显改善,在保证钢带质量与力学性能的同时,大幅度降低了08A1钢脱氧合金化成本,取得了明显的经济效益,开拓了产品市场.     

铝及铝合金电镀

铝及其合金是应用最广泛的五大基体之一.它具有良好的导电性、传热快、密度小、强度高、易成型等优点,随着现代工业的发展,广泛应用于交通工业、航空工业、建筑装潢、日常生活.但铝和铝合金硬度低、不耐磨、易发生晶间腐蚀,这些缺点影响了其应用范围和使用寿命.经过电镀后,可扬长避短增加防护-装饰性作用,延长其寿命,扩大应用范围.     

铝及铝合金在熔融纳中的腐蚀行为

研究了纯铝、Al-Si和AL-Mg合金在350～450℃熔融钠中的腐蚀行为。采用OM、XRD、EDAX和EPMA分析了腐蚀产物的组织形貌和合金元素的分布。实验结果表明高纯铝受到轻微的腐蚀,并非完全“免蚀”。工业纯铝的腐蚀较明显,主要发生在杂质偏聚的晶界附近。铝合金的腐蚀程度取决于杂质元素尤其是硅的含量。铝中添加一定量的镁并用微量锆细化晶粒可改善合金对熔融钠的耐蚀性。铝和铝合金的腐蚀产物经测定为AINaSi相。     

铝及铝合金仿木纹着色技术

综述了铝及铝合金的性能、应用领域、表面处理的方法及将来的发展趋势.着重阐述铝及铝合金仿木纹着色的发展潜力、仿木纹着色不同方法及其特点和木纹形成原理,尤其对电化学法形成木纹的不同工艺及原理作详细的论述,其中包括电化学法木纹处理工艺的体系及组分作用、去膜工艺、阳极氧化、着色和封闭等工序,提出了铝及铝合金仿木纹着色的应用前景及未来发展方向.     

Early pore formation in aluminium foams studied by synchrotron-based microtomography and 3-D image analysis

The mechanisms behind pore formation in aluminium alloys that are in commercial use for making foam components are still not understood. It is accepted that they play a key role in the quality of the evolving pore structure. In order to shed light on early pore formation, aluminium foams in low expansion stages made by the powder-compact melting process were investigated by synchrotron-based hard X-ray microtomography and quantitative image analysis. The calculated spatial correlation functions between the gas source (TiH₂ particles) and the nucleating pores show that the location of pore formation and the spatial gas source distribution for AlSi7 and Al–Si–Cu alloys are essentially independent. Therefore, in the alloys investigated, the position of the melt formation is found to determine the pore nucleation rather than the spatial distribution of TiH₂. This behaviour explains the known positive effect on the pore structure achieved by adding copper.     

Thixoforming of EN AW-2014 alloy at high solid fraction

EN AW-2014 extruded alloy slugs were thixoformed at 615 °C where the solid fraction is estimated to be 80%. The recrystallization process occurred during heating to the thixoforming temperature, between 550 °C and 600 °C, well above the solidus temperature owing to the pinning of grain boundaries by Al₂Cu precipitates. The equiaxed polygonal grains thus obtained have become increasingly globular upon soaking. Si was enriched in the grain boundaries during soaking while the solid solution matrix was gradually depleted off Cu. The grain boundary composition has moved closer to that of the Al-Cu-Si ternary eutectic with a lower melting point than the binary Al-Cu eutectic, facilitating grain boundary melting. The liquid phase has then penetrated between the grains, forming a more or less continous intergranular network. Microstructural features essential for forming in the semi-solid state were obtained after about 10 min at 615 °C. The subsequent forming process has occurred in the semi-solid state with no evidence of grain deformation. The thixoformed EN AW-2014 part was solutionized at 500 °C for 2 h and was subsequently quenched in water. Artificial ageing at 160 °C has produced hardness values as high as 160 HV after only 8 h. It is concluded that the high strength wrought EN AW-2014 alloy feedstock processed by the RAP route respond to a thixoforming operation in a very favorable fashion.     

Response to annealing treatments of twin-roll cast thin Al–Fe–Si strips

The new generation twin-roll casters are able to cast strips down to 1 mm and offer a notable increase in the casting speed and caster productivity. The thin strips, however, experience profoundly different temperature and deformation gradients in the caster roll gap and may thus require different down stream processing cycles. An attempt was made in the present work to identify the structural features of the thin-cast AlFeSi strip and its response to high temperature annealing treatments. The deformation introduced to the thin AlFeSi strip in the caster roll gap was largely restored by dynamic processes before coiling, producing recrystallized surface layers. When annealed as-cast, the grain structure was rearranged by an ordinary growth process at the surface and via recrystallization in the interior. The entire process was retarded due to the precipitation reactions, particularly in the immediate vicinity of the surface where the supersaturation of the aluminium matrix was the highest and the boundary mobility was severely impaired. The final strip structure was a coarse one. The entire section of the thin strip underwent recrystallization when the thin strip was annealed after a rolling pass. While some improvement appeared to be possible in this practice, a heterogeneous through thickness structure with relatively coarser surface grains prevailed.     

铝在盐酸介质中的缓蚀研究

在０．５ｍｏｌ／Ｌ ＨＣｌ介质中分别加入不同浓度柠檬酸、丙烯酸、顺丁烯二酸，研究了脂肪酸浓度和温度对铝腐蚀速度的影响。结果表明，柠檬酸具有较好的缓蚀使用。测定了不同介质中铝的极化曲线，探讨了其缓蚀机理。     

Fabrication and behaviour of Al–Si/SiC composite in cavitation conditions

Aluminium matrix composite (AMC) specimens were prepared using the compocasting technique. The reinforcements used were silicon carbide (SiC) particles with an average size of 30 μm. The influence of reinforced ratio of 10 wt-%SiC on cavitation behaviour was examined. The cavitation resistance of an AMC with SiC (AlSi/SiC) was evaluated using an ultrasonically induced cavitation test method. The mass loss of specimens was measured by an analytical method. The morphology of the damaged surface of tested composite was examined using scanning electron microscopy (SEM). It is shown that the cavitation rate of an AMC with SiC is almost the same as the CA6NM stainless steel, which is largely used in the production of hydraulic machinery components. Because the results show that the composites exhibited very good resistance to the cavitation erosion, this material can be successfully used under conditions where the cavitation resistance is needed.     

Rescaled range analysis of the corrosion potential noise

Rescaled range (R/S) analysis of random events is known to reveal the persistent or antipersistent nature of the process. Time records of corrosion potential noise, i.e. spontaneous voltage fluctuations with zero current, were collected from freely corroding pure aluminium samples in a number of different electrolytes. The results of the R/S analysis, also compared with those of simulated time series, revealed long term correlations, the nature of which were seen to be characteristic to the corrosion processes. The differences between the R/S patterns of general and pitting corrosion have been found to be particularly distinctive.     

新型高效全自动铝锭堆垛机的设计

针对目前我国电解铝厂使用的国产铝锭堆剁机的效率较低、稳定性较差等问题,通过对其结构、工作原理和运动特点的分析与研究,设计了一种新型高效全自动铝锭堆垛机.经论证该型堆垛机具有较高的抗震、通用、稳定和生产效率高等优点.