铜带对接TIG焊接专机的开发应用

为了有效利用铜带材料,消除铜带轧制生产过程中引带,同时使小卷料适应大精轧设备高吞吐量的需要,开发了由PLC控制、对料头/料尾有剪切修边功能、能自动对中的铜带纵缝专用TIG焊接设备,并在铁青铜带的焊接中得到了良好的应用。结合铁青铜的物理特性,改进焊接工艺与流程,达到了焊接变形小、焊缝单面焊双面成形的效果。适当地修改焊接控制程序,可应用于其他有色金属带材的焊接。     

自动冷镦机料端安全切断的工作原理

为使自动冷镦机正常生产,有比较高的开机率,人们十分重视料头的排除问题.《锻压机械》1983年第3期介绍了"自动冷镦机去料头与防止出现短料的措施"一文,其中列举了出现料头和短料的三个原因,及采用挡料器的感触机能去料头和计数法自动去料头的措施.在计数法自动去料头的措施中介绍了机械计数     

铝扁管挤压生产线收卷系统的设计

常规挤压生产线的后部出料系统不能实现铝扁管产品的收卷功能,本文研制了铝扁管挤压生产线专用的收卷系统。该收卷系统有两个收卷盘,三个工位,卷盘与主动轴及从动轴采用分体式结构,柔性结构的导向装置自适应强,稳定可靠地自动固定料头的料头固定组件,可轴向伸缩的压料轴装置,确保了收卷装置的顺利可靠运行。生产实践证明,该收卷系统实现了挤压铝扁管的自动收卷,提高了生产线的生产效率及产品质量。     

镀锌生产线中的CO2激光焊机

针对镀锌生产线的特点,设计了镀锌生产线中CO2激光焊机的总体结构,主要由出(入)口单元和激光焊机设备单元组成。介绍了镀锌生产线CO2激光焊接原理及其CO2激光器的结构。研究了CO2激光焊机的光路系统,在带尾(带头)准备时,激光通过剪切头完成带尾(带头)的剪切。在焊接过程中,激光通过焊接头完成钢板的焊接。CO2激光焊机的伺服系统极其复杂,由14个伺服电机完成:激光架生产线方向移动、带钢间隙生产线方向调整、激光架过程梁方向移动、带钢手动对中调整、带钢入(出)口对中调整、压轮过程梁方向移动、剪切头竖直方向移动、焊接头竖直方向移动、带钢中性层调整。     

自动冷镦机去料头与防止出现短料的措施

在自动冷镦机生产过程中,因为出现短料头,往往使生产不能连续进行,因而影响自动冷镦机生产率的提高。文中对短料出现的原因、危害作了说明,介绍了自动去料头机构和防止出现短料的措施。可供从事自动冷镦生产工作人员参考。     

遥测遥控技术在焊接中的应用

在对遥测、遥控技术的现状进行述评的基础上，探讨了二遥技术在焊接中的应用。指出二遥技术可用于焊接规范控制、焊缝跟踪、熔池控制等方面，因而二遥技术将在水下焊接、空间焊接及焊接机器人构成的焊接生产线中得到应用。     

技术市场

触头焊接生产线是用来加工小容量接触器触桥用的，可双排加工、焊接触头、无屑攻丝、成型、落料。加工速度440件／分，提高效率40倍，有全部技术资料，可技术转让。衔铁生产线是参照西门子公司设备设计制造的铁芯铆压生产线，由推片、测厚、补片、穿钉、铆压、输送、测量、剔出等装置，共十个工步和液压系统、电控系统组成。生产节拍门一155，每次加工两件。提高效率40—45倍，可技术转让。装配生产线是自行设计制造的装配生产线，自用，生产近十条，并为兄弟厂生产了十来条生产线，均使用良好，有特殊要求也可重新设计制造。AID－1绕线机…     

电池极片激光焊接半自动化生产线设计

针对手机电池的极片与电池壳体的激光焊接,设计了半自动化生产线系统,主要由自动上料组件、夹紧组件、输出镜头组件、下料机构组成,其中上料部分由储料器和推料机构组成;下料机构由推料机构、翻转机构、运动皮带组成。整个焊接生产线为半自动形式,提高了生产效率及保证了产品质量。     

精度焊接生产线规划

分析了精度焊接产品及其特点，提出精度焊接生产线规划的4个关键问题：广义工艺规划、生产规划、生产线布局及精度焊接的多元质量控制规划；针对各关键问题讨论了精度焊接生产线规划阶段的相应对策。根据精度焊接生产线规划的要求，提出了结合虚拟制造技术和现代优化算法的集成规划方法，并建立了相应的规划仿真环境，时精度焊接生产线规划具有参考价值和指导作用。     

转向架数字化焊接生产线

车体和转向架的焊接技术是高铁生产制造中至关重要的核心技术。通过策划转向架焊接智能焊接生产线的方案,包含运营管理系统、焊接过程管理系统、生产线控制系统的方案探讨,对多维度生产要素进行融合与串联,为动车组转向架智能焊接生产线提供了可供借鉴的解决方案。     

PWM逆变器残余误差的神经网络消除方法

在分析现有PWM逆变器控制技术的基础上,讨论了单相PWM逆变器残余误差产生的机理,构造出单相PWM逆变器残余误差的神经网络消除模型,论述了神经网络训练样本拾取方法。该控制方法能有效地提高PWM逆变器的输出精度.     

Metastable pitting behaviour of austenite stainless steel under compressive residual stress

Metastable pitting behaviour of austenite stainless steel after compressive deformation in an acidic NaCl solution was investigated. The results show that the pit initiation rate increases while both metastable pit lifetime and growth rate decrease after compressive deformation. Meanwhile, the ratio of the surface oxide fraction of Cr to Fe increases whereas the average size of stable pits is smaller and shallow disk-shaped under compressive residual stress. The results reveal that with the aid of enrichment of Cr oxides and compressive residual stress, which helps break the remnants of the undermined passive film, pit repassivation can be accelerated.     

FIB/SEM study of AA2024 corrosion under a seawater drop,part II

The dissolution of S-phase clusters in aluminium alloy 2024 (AA2024) exposed to a 0.5 μl seawater droplet is presented. Foils for transmission electron microscopy (TEM) were made from local attack sites using a focussed ion beam/scanning electron microscope (FIB/SEM). The sections showed that clusters of S-phase particles underwent dealloying. The resulting copper sponge morphology, banding, preferred orientation and crystal defect structure as a result of plastic deformation have been characterised. With build-up of amorphous corrosion product, physical and electrical isolation of parts of the clusters developed, with the result of copper dissolution from the S-phase remnants.     

Localized corrosion of 2024 T351 aluminium alloy in chloride media

The corrosion behaviour of 2024 T351 alloy was studied in chloride solutions. The polarization curve of this alloy showed two breakdown potentials. The first was related to the dissolution of the coarse intermetallic Al₂CuMg particles. A severe Mg dealloying of the particles resulted in Cu-rich remnants. The matrix surrounding the particles was systematically found to be dissolved. Indeed, the particles are surrounded by a dispersoid-free zone which is anodic in comparison to both the rest of the matrix and the S phase particles. The second breakdown potential corresponded to the matrix breakdown potential. Pits but also intergranular corrosion developed. Grain boundaries were preferentially attacked because they are anodic in comparison to the grain body and the previous dissolution of the intergranular precipitates made them fragile.     

Thermal Expansion Coefficient and Mechanical Properties of Friction Stir Welded Invar (Fe-36%Ni)

Two high-temperature pin tools, one a polycrystalline cubic BN and the other of W-25%Re, were used to friction stir weld 12.7 mm thick Invar (Fe-36%Ni) plate. Successful welds were produced at a rotational speed of 600 rev min⁻¹ and travel speeds of 76, 102, and 127 mm min⁻¹. The coefficient of thermal expansion, tensile strength, and microhardness of the welds were measured and found to be essentially unchanged from the parent material. The measured elongation was 52% for the parent material and 30 and 37% for welds made with the W-Re and the polycrystalline cubic BN pin tools. Both pin tools produced comparable welds but the W-Re tool exhibited more wear and left small wear remnants in the weld especially at the weld plunge.     

Zur Frage des Lochfraßes bei Kupferrohren in Trinkwasserleitungen

The problem of pitting corrosion with copper pipes in drinking water mains Investigations into cases of corrosion observed on copper pipes of water mains in Vienna and Linz have given rise to some useful practical knowledge concerning corrosion prevention: Lengthy periods of stagnation after the installation are detrimental whilst short periods of stagnation are beneficial. This is because, in the latter case, protective layers (Cu₂O) are formed whilst, in the former case — and especially if there is no intermediate rinsing — the sedimentation of suspend matter is liable to cause the formation of a non-uniform cover layer. The thickness of the cover layer must not exceed a certain critical value as the elasticity of the layer would otherwise decline so that metal would be bared when the pipe is bent. Soldering at the time of installation calls for great care since soldering remnants are, in principle, detrimental. In contrast, the aggressivity of the water (ions, sedimentations) is not of major importance if the above-mentioned conditions are met.     

Localized corrosion mechanism associated with precipitates containing Mg in Al alloys

To clarify the localized corrosion mechanism associated with precipitates containing Mg in Al alloys, the simulated bulk precipitates of S and β were synthesized through melting and casting. Their electrochemical behaviors and coupling behaviors with α（Al） in NaCl solution were measured. Meanwhile, simulated Al alloys containing S and β particles were prepared and their corrosion morphologies were observed. It＇s found that there exist two kinds of corrosion mechanisms associated with precipitates containing Mg. The precipitate of β is anodic to the alloy base, resulting in its anodic dissolution and corrosion during the whole corrosion process. While, there exists a corrosion conversion mechanism associated with the S precipitate, which contains active element Mg and noble element Cu simultaneously. At an initial stage, S is anodic to the alloy matrix at its periphery and the corrosion occurs on its surface. However, during its corrosion process, Mg is preferentially dissolved and noble Cu is enriched in the remnants. This makes S become cathodic to a（Al） and leads to anodic dissolution and corrosion on the alloy base at its periphery at a later stage.     

等离子弧焊熔敷Ti-6Al-4V合金原位拉伸过程中显微组织及应变响应的电子背散射衍射表征

航天级钛合金的新型叠层制造技术（ALM）的优势体现在较低的制造成本等方面,并可替代传统加工成型工艺。由等离子弧焊熔敷叠层制造技术制备Ti-6Al-4V合金的显微组织由定向凝固生长的β柱状晶及在其晶内生长的细小的α片层组织构成。在原位拉伸过程中结合应用高速离线电子背散射衍射表征（Offline EBSD）可快速获取试样显微组织和形变特征之间的关系。揭示出不均匀变形的发生取决于柱状晶界间的应变响应。柱状滑移和基面滑移系统被激活进而导致最后出现形变滑移线,即在某些柱状晶中滑移扩展至整个晶粒;而在另一些晶粒中表现为存在应变梯度和应力集中的地方发生形变失配。形变的扩展习性受制于定向凝固生长的柱状晶生长方向及其之间的界面取向关系。在垂直于柱状晶方向的拉伸试验揭示存在剧烈的变形局域化。基于原位拉伸观测及高速的离线电子背散射衍射表征结果,本文作者提出从微观到宏观形变扩展的控制机制。     

Microstructure and Strength of Al2O3 and Carbon Fiber Reinforced 2024 Aluminum Alloy Composites

The microstructure and mechanical properties of 2024 aluminum alloy composite materials strengthened with Al₂O₃ Saffil fibers or together with addition of carbon fibers were investigated. The fibers were stabilized in the preform with silica binder strengthened by further heat treatment. The preforms with 80-90% porosity were infiltrated by direct squeeze casting method. The microstructure of the as-cast specimens consisted mainly of α-dendrites with intermetallic compounds precipitated at their boundaries. The homogenization treatment of the composite materials substituted silica binder with a mixture of the Θ phase and silicon precipitates distributed in the remnants of SiO₂ amorphous phase. Outside of this area at the binder/matrix interface, fine MgO precipitates were also present. At surface of C fibers, a small amount of fine Al₃C₄ carbides were formed. During pressure infiltration of preforms containing carbon fibers under oxygen carrying atmosphere, C fibers can burn releasing gasses and causing cracks initiated by thermal stress. The examination of tensile and bending strength showed that reinforcing of aluminum matrix with 10-20% fibers improved investigated properties in the entire temperature range. The largest increase in relation to unreinforced alloy was observed for composite materials examined at the temperature of 300 °C. Substituting Al₂O₃ Saffil fibers with carbon fibers leads to better wear resistance at dry condition with no relevant effect on strength properties.     

The Center for Microanalysis of Materials

“Excuse me,” said a graduate student that I’ve not seen before, “I’d like to get some time on the Auger.” “Fine” I reply, “If you are going to need a lot of time, Nancy will train you so that you can use the machine yourself. If it’s only a small project, she’ll work with you. In either case, see Nancy to get a session scheduled.” Shaking off the last remnants of sleep, I realize that I’ve forgotten the most important question, “Oh, just a minute …. Why? … I mean, what do you want to find out?” And so begins a discussion which leads to the recommendation that, instead of Auger spectroscopy, the student use a combination of SIMS and STEM. We schedule time appropriately.