铝合金熔炼中永磁搅拌的应用效果

永磁搅拌器是近期国内发展起来的铝熔体搅拌设备,它具有造价低,故障率低、使用寿命长、能耗低等特点,使用效果显著。通过在生产场采用永磁搅拌与人工搅拌熔体的一系列对比工艺试验,验证了在熔炼铝合金中使用永磁搅拌可缩短熔炼时间,熔体化学成分均匀,熔体温度均匀,减少烧损、渣损,能耗低,效益可观,改善劳动条件。     

Ti-6Al-4V合金双半球结构脉冲电流辅助超塑成形

针对Ti-6Al-4V合金板材超塑成形能耗高、效率低的问题,提出了一种脉冲电流辅助超塑成形工艺。该工艺将成形坯料直接串联到脉冲电流回路,利用脉冲电流迅速将坯料加热至超塑成形温度。通过脉冲电流加热实验,分析了平均脉冲电流密度对坯料温度及升温速率的影响。结果表明,采用该加热方式可将坯料加热时间从数十分钟缩短至几十秒,能量消耗降至传统工艺的20%左右,极大地提高了加热效率、降低了能耗,实现了节能环保的绿色超塑成形技术。利用该工艺成形了Ti-6Al-4V合金双半球结构,并分析了在脉冲电流辅助工艺条件下细晶态Ti-6Al-4V合金的超塑变形机制。     

铁液温度是生产高质量铸铁件的基础——从铁液温度看我国冲天炉熔炼技术的发展方向

详细介绍了冲天炉铁液温度与能耗的关系,综述了铁液温度对铁液冶金质量、球化与孕育处理效果、铸件力学性能等的影响情况,认为我国冲天炉铁液温度提高到1 500～1 550℃,既能推动我国铸铁件质量的提升,也能综合解决冲天炉铁液质量、节能、环保问题。     

激光增材制造过程中激光与粉末的相互作用研究现状

激光增材制造是通过激光加热熔化粉末或丝材并逐层叠加而形成所需工件的一种增量制造技术。该技术涉及非常复杂的非平衡物理和化学冶金过程,在加工过程中易产生非平衡组织和晶粒取向。激光与粉末的相互作用过程是整个加工过程中最为重要的部分,系统总结激光与粉末的相互作用对于增进对激光增材制造技术的理解,进而提升工件性能具有重要的意义。按照送粉式与铺粉式激光增材制造两种加工方式,分析了激光能量的衰减、粉末颗粒温度的上升以及激光-粉末-熔池的相互作用,综述了激光与粉末相互作用的研究现状。     

脉冲进气旋转喷吹技术的水力模拟

在铝合金熔体净化旋转喷吹技术的基础上 ,采用水力模拟实验研究了脉冲进气方式对气泡大小的影响。实验结果表明 :脉冲进气方式有利于产生射流 ,使气泡变小 ,并增加了气泡与熔体接触的比表面积 ,从而改善了除氢的动力学条件 ,有利于提高除氢效果。     

激光能量输入对直接激光沉积莫来石陶瓷组织性能的影响

研究了激光能量密度对直接激光沉积熔体自生莫来石陶瓷孔隙/密度、微观组织和力学性能的影响.结果表明,较低激光能量密度(15 J/mm2)所制备的陶瓷样件边缘分布有尺寸较大的气孔,使得样件整体孔隙率较高,且表面粘粉严重,这与成形扫描速度大和硅酸盐熔体粘度高有关.而较高激光能量密度(90 J/mm2)虽然可以获得表面光滑、莫...     

铝电解槽破损判定标准的分析与探讨

铝电解技术迅猛发展,原铝直流电单耗等核心技术经济指标取得较大提升,电解槽槽龄有的已达到3000天,但电解槽破损漏炉发生熔断主体导电母线迫使系列停产风险依然存在,给电解生产带来重大隐患.本文根据生产实际摸索出铝电解槽破损的判定标准,对电解槽进行科学有效控制,可以防止电解槽漏炉事故,为电解系列连续平稳生产提供有力保障.     

Progress on Numerical Simulation of Vibration in the Metal SolidificationEI北大核心CSCD

The application of vibration technology to the metal solidification process can not only effectively improve the solidified structure and the performance of castings, but also have the advantages of low cost, energy saving and environmental protection. Therefore, the application of vibration technology in metal solidification has been extensively studied in experiments. However, due to the high temperature and opacity of the metal melt, hindering its measurement and observation, the mechanism how the vibration affects the solidification is not fully understood. Numerical simulation can provide the variation law of various parameters such as flow field, temperature field and stress field under vibration condition, which helps us understand the mechanism of vibration more thoroughly. Meanwhile, the numerical simulation of the influence of vibration on the solidification of metal melt has been much less systematically studied. This paper introduces the research progress of numerical simulation of vibration applied in metal solidification. The main vibration modes include ultrasonic vibration, mechanical vibration and pulsed electromagnetic vibration. The application mainly includes melt processing, filling, solidification, purification and ageing process of numerical simulation. The current research status of numerical simulation theory and technology of vibration applied in all aspects of casting was summarized systematically. Furthermore, the future research directions of numerical simulation of vibration in metal solidification process were prospected.     

SY200铝电解槽铝液流态优化节能技术研究与应用

在正常生产槽上采用直接加阻流块稳定液体流速的方法降低电耗,在技术条件基本不变化的情况下直接降低电压100mV,对电流效率没有影响,吨铝可降低能耗200kWh～300kWh.     

纳秒激光加工中脉冲能量对熔体体积的影响

目的 考察调节激光脉冲能量对纳秒激光加工中熔体体积控制的途径。方法 通过纳秒激光加工实验中的微结构火山口相对高度随脉冲能量的变化规律,来间接反映熔体体积随脉冲能量的变化规律。在MATLAB环境下,通过有限元法基于双温模型模拟,研究纳秒激光脉冲作用于铝合金材料表面时脉冲能量对熔体体积的影响规律。结果 在低能量密度下,可实现低于10%的火山口相对高度,远低于文献记载的高能量密度下~100%的火山口相对高度。随着激光脉冲能量的增加,模拟结果和实验结果都表明熔体体积随能量密度的增加而略有减少,这与文献模型相悖。结论 在较宽的能量范围内,纳秒激光加工产生的熔体体积随激光脉冲能量密度的变化规律符合C Körner等人提出的模型,表明通过控制激光能量密度能够有效控制纳秒激光加工中的熔体体积。然而,在较低的能量密度下,熔体体积随能量密度反常变化规律意味着有其他因素伴随能量密度共同影响熔体体积,这种影响还有待进一步研究。     

预焙铝电解槽阳极底部开排气沟对电解质流场的影响

对预焙铝电解槽阳极底部开排气沟时周围电解质流场进行计算,发现部分阳极气体可以通过排气沟向外排放,减少气泡在阳极底部停留时间和阳极底掌气泡覆盖率,从而有利于降低极间电阻压降和阳极效应系数,减少电解能耗;另一方面气体带动电解质进入排气沟,然后进入电解槽侧部通道,扩大了电解质循环通道,促进了阳极周围电解质流动和槽内的传质传热,有利于保持电解正常进行,相比之下排气沟为通沟时较非通沟更有利于保持电解质流动稳定;同时由于排气沟促进了阳极气体排放,使铝液与阳极气体发生“二次反应”(即电解还原的铝卷入电解质中被阳极气体重新氧化)的机会减少,有利于提高铝电解电流效率。     

Magnequench magnets status overview

The advent of neodymium-iron-boron materials having excellent magnetic properties and potential economic advantages has initiated a new era in permanent magnet technology. One method of making these magnets is by the rapid solidification process. It is typically carried out by melt spinning, which produces a highly stable, dmagnetically hard microstructure powder, directly from the melt. This can be used for bonded magnet applications. Alternatively, this powder can be hot pressed to produce fully dense isotropic magnets with energy products up to 15 MGOe. Anisotropic magnets with energy products ranging up to 50 MGOe can be produced by thermomechanical orientation or hot deformation process. Current processing and properties of Magnequench (General Motors) materials are reviewed, das well as the applications and advances of these materials. The advances include high-temperature bonded magnet and high-energy product anisotropic bonded and fully dense magnets.     

我国铸造有色合金及其特种铸造技术发展现状

结合我国在铸造有色合金领域的发展概况,从合金发展、应用和有色合金熔体技术以及特种铸造在有色合金中的应用角度,分析了五十年来我国在该领域所取得的成绩和存在的问题,以引起广大科技工作者和生产技术人员对这方面自主创新的重视,不断提高铸造有色合金的技术水平,扩大其应用领域。     

脉冲进气精炼铝合金熔体的水力模拟研究

本文将带气体动力脉冲器的转头应用于铝合金熔体净化旋转喷吹技术当中，并通过水力模拟实验，研究了脉冲进气方式对气泡大小的影响。结果表明：带气体动力脉冲器的转头可以产生强烈的脉冲射流，在相同的气体流量和转头转速等条件下，脉冲射流比连续射流更容易得到小尺寸气泡，更有利于氢的排除。     

Emerging melt quality control solution technologies for aluminium melt

The newly developed "MTS 1500" Melt Treatment System is performing the specifically required melt treatment operations like degassing, cleaning, modification and/or grain refinement by an automated process in one step and at the same location. This linked process is saving time, energy and metal losses allowing-by automated dosage of the melt treatment agents-the production of a consistent melt quality batch after batch. By linking the MTS Metal Treatment System with sensors operating on-line in the melt, i.e., with a hydrogen sensor "Alspek H", a fully automated control of parts of the process chain like degassing is possible. This technology does guarantee a pre-specified and documented melt quality in each melt treatment batch. Furthermore, to ensure that castings are consistent and predictable there is a growing realization that critical measuring the cleanliness of an aluminum melt but these can be both slow and costly. A simple, rapid and meaningful method of measuring and bench marking the cleanliness of an aluminum melt has been developed to offer the foundry a practical method of measuring melt cleanliness.This paper shows the structure and performance of the integrated MTS melt treatment process and documents achieved melt quality standards after degassing, cleaning, modification and grain refinement operations under real foundry conditions. It also provides an insight on a melt cleanliness measuring device "Alspek MQ" to provide foundry men better tools in meeting the increasing quality and tighter specification demand from the industry.     

微脉冲MIG焊技术在修复工模具中的应用

微脉冲MIG焊技术采用断续的微脉冲电弧的能量，将可熔性电极材料熔融，连续不断地堆焊到工件表面，形成堆焊修补层，这种技术适用于修补成型模具，热锻压模具及各种塑料模具的铸造缺陷，磨损，小面积局部剥落，损伤，划沟等。     

应用于铸造厂的除尘公用系统设计

铸造行业的节能降耗分为两种途径:一种是显性的节能,通过设备改进等措施实现;另一种是隐性的节能,即可在单位产品质量的能耗指标上体现的节能,需要通过提高生产技术水平来实现.本文以铸造厂所用的除尘系统为研究对象,提出了一种应用于熔炼和砂处理环境的能够节省空间、节省建设成本、节省运行能耗,且便于控制的除尘公用系统.     

基于超疏水表面的主被动复合防/除冰技术研究进展

介绍了光热、电加热、磁能、声波能与超疏水表面相结合的主被动复合防/除冰技术及其机理与应用，阐述了以上复合型防/除冰技术的优势与不足。其中，光热复合技术具有耗能低、材料选择多样化等优点；电加热复合技术工艺简单，易于规模化制造；磁能复合技术可满足复杂场景的防/除冰应用需求；声波复合技术则具有结构简单的优势。此外，同时复合多种能场可进一步提升防/除冰工作效率，是主被动复合技术的发展趋势之一。最后，阐述了基于超疏水表面的主被动复合防/除冰技术的不足之处，并展望了复合防/除冰技术的应用研究前景。     

Application and study in aluminum melt degassing technologies

The classification, characteristics and current situation of aluminum melt hydrogen-removal methods and technologies have been summarized. The latest studies and research results of aluminum melt degassing technology have been summed up. The tendency and prospect of aluminum degassing technology was discussed.     

脉冲TCGMAW电流占空比对熔滴过渡和焊缝成形的影响

基于建立的熔滴过渡高速摄像分析系统,对高速脉冲TCGMAW在脉冲电流占空比变化下的熔滴过渡过程进行观察分析,并就脉冲电流占空比变化对熔滴过渡和焊缝成形质量的影响进行了研究。试验结果表明,在所用焊接规范下,当脉冲电流占空比较小时,焊丝熔化速度不能与送丝速度匹配,熔滴过渡方式表现为短路过渡形式,焊缝成形较差,甚至出现断弧、焊不起来的情况;随着脉冲电流占空比的提高,焊丝熔化能量加大,熔滴过渡方式逐渐过渡到射滴过渡和射流过渡,电弧电压的波动范围变小,焊缝成形良好。