Effect of Copper Coating and Reinforcement Orientation on Mechanical Properties of LM6 Aluminium Alloy Composites Reinforced with Steel Mesh by Squeeze Casting

Uncoated and copper coated steel wire mesh reinforcing LM6 aluminium alloy composites have been produced using squeeze casting process by varying reinforcement orientation viz., 0°, 45° and 90° respectively. Microstructure of the castings has been examined and mechanical properties such as hardness, tensile strength and ductility have been investigated. Fracture surface of tensile specimens has been analysed using field emission scanning electron microscope. Microstructure of samples reveals that copper coating on steel wires improves the interface bonding between matrix and reinforcement. Average hardness values of 259 and 90 Hv have been observed in steel wire and matrix respectively. Tensile strength of composites increases with increasing angle of reinforcement orientation from 0° to 90°. Tensile strength increases up to 11% by reinforcing copper coated steel wire mesh at 90° orientation as compared to LM6 aluminium alloy. Fracture surface of composites shows pullout of steel wires in uncoated steel wire mesh composites and broken wires in copper coated steel wire mesh composites respectively. Dimples have been observed on the fracture surface of LM6 aluminium alloy. In general, copper coated steel wire mesh composites offer better hardness and tensile strength compared to uncoated steel wire mesh composites and LM6 aluminium alloy. This may be attributed to the copper coating on steel wires which results better interface bonding between matrix and reinforcement.     

Application of immersive copper coatings with high adhesive strength to steel welding wire

Immersive copper coatings deposited on steel from sulfate solution with no special additives have practically no adhesion to the base. Special materials must be selected to inhibit associated cathodic and anodic reactions in the contact reduction of Cu²⁺ ions on the steel. Immersive deposition of a copper substrate on the steel ensures the necessary adhesion of subsequent galvanic coatings. A process for the application of a copper coating to steel welding wire is developed.     

连续滴定法测定钢帘线镀层中铜和锌

研究了以亚甲蓝-PAN-6S作混合指示剂,EDTA滴定法测定钢帘线镀层中的铜和锌.在pH 5.4的六次甲基四胺-盐酸缓冲介质中,以亚甲蓝-PAN-6S试剂作络合滴定指示剂,以EDTA为滴定剂进行了铜和锌的连续滴定,终点颜色变化敏锐,准确度高,铜锌比例在1∶10～10∶1范围之间相互无影响.方法可用于钢帘线镀层中铜、锌的测定,结果满意.     

铜、铝连续挤压技术特点及工业应用

在简叙连续挤压和连续包覆技术的工作原理基础上，重点介绍应用该种方法制造制冷用管技术、有线电视同轴电缆(CATV)外导体、铁路通信信号电缆护套技术、铝包钢丝技术、铜接触线技术及铜扁线技术。分析了该新工艺在上述几项工业应用领域应用的主要特点和应用现状。介绍了当前我国在铜铝加工新技术方面的突破。     

铜包钢接触线的感应加热控制模型研究

铜包钢接触线属于高速铁路建设急需的产品,该产品的制造在中国尚属起步阶段.在采用连续挤压包覆技术生产铜包钢接触线时,钢丝的预热温度对产品的质量有重要的影响.在感应加热理论和热传导理论的基础上,建立了钢丝感应加热时的温度场模型,定性、定量地研究了表面比功率、表面功率、加热速度、钢丝直径、导热系数、导温系数等参数之间的关系,并对钢丝运行的在线加热建立了感应加热的热计算模型,实施了钢丝连续运行感应加热的计算和自动控制,在铜包钢接触线制造上取得了较好的效果.     

Insight into physicomechanical and tribological properties of copper galvanic coatings formed with the addition of electroerosion copper nanopowder

The results of studying the properties of copper galvanic coatings fabricated using an L1-210 v2 galvanic installation (Italy) using the bright copper plating electrolyte produced by 24 Karata (Moscow) and the addition of electroerosion copper nanopowder fabricated by the electroerosion dispersion (EED) method using copper wire scrap in distilled water are given. An original setup developed by the authors (RF Patent 2449859) was used for the EED of conductors. The friction coefficient and wear factor found when testing coatings using a Tribometer automated friction machine (CSM Instruments, Switzerland) indicate the absence of substantial distinctions in the wear resistance of the samples. Surface hardness tests of the sample were performed using a DM-8 automated microhardness tester according to the micro-Vickers method with an indenter load of 25 g by ten imprints with a free selection of the indentation point according to GOST (State Standard) 9450–76. The indenter loading time was 15 s. It is established that the microhardness of a copper coating with the addition of copper nanoparticles is 15% higher than that of steel substrate and the sample with a standard copper coating.     

铝包钢丝中频加热的模糊神经网络控制技术

在铝包钢丝生产过程中,采用在线中频感应加热方式。基于中频感应加热条件,针对钢丝直径、钢丝运行速度、加热温度、中频频率、中频电压、中频电流、中频功率、加热炉长度之间的函数关系,建立了连续包覆过程的多变量神经网络控制方法。经过多次实验和筛选,选出有效数据,多个模式反复学习,直至网络全局误差函数E小于预先设定的一个极小值。通过网络训练和仿真分析得到较佳的解决方法,该方法应用在铝包钢丝连续包覆生产线上,较好地解决了钢丝加热控制难的问题。     

Coatings of nanocrystalline metallic wires on steel substrate: mechanical characteristics of coating layer

Coatings are produced by wire arc spraying on a steel surface and the effect of coating thickness on the coating characteristics in terms of microhardness, residual stress and friction coefficient are examined. The wire used during coating is composed of FeCrBMnSi, which comprises nanocrystalline and amorphous phases. The twin wire arc spray system was incorporated to generate different coating thicknesses on steel substrate. The analytical tools including three-dimensional imaging optical and scanning electron microscopes, energy dispersive spectroscopy and X-ray diffraction (XRD) are used to assess the coating characteristics. It is found that the surface texture and surface roughness of the coatings change with coating thickness. Thus, reducing the coating thickness results in slightly increased texture height and surface roughness. Microhardness is almost 15% higher for the thin coating (300?μm) than the thick coating (550?μm). The residual stress developed in the coatings is tensile and it changes with coating thickness, such that it reduces for thick coating.     

Influence of Zn Coating on Interfacial Reactions and Mechanical Properties During Laser Welding-Brazing of Mg to Steel

To investigate the influence of Zn coating on the joining of magnesium alloy AZ31?to Zn-coated steel, dissimilar metal joining both with and without Zn coating was performed by the laser welding-brazing (LWB) process. Welding characteristics including joint appearance, identification of interfacial reaction layers, and mechanical properties were comparatively studied. The results indicated that the presence of Zn coating promoted the wetting of liquid filler wire on the steel substrate. Heterogeneous interfacial reaction layers formed along the interface between the Mg alloy and Zn-coated steel, whereas no distinct reaction layer and increased concentration of Al were identified at the interface between the Mg alloy and noncoated steel. The maximum tensile-shear strength of Mg/steel lap joint with Zn coating reached 180?N/mm, which was slightly higher than that achieved without Zn coating (160?N/mm). Failure of joint in both cases occurred at the interface; however, the fracture mode was found to differ. For Zn-coated steel, the crack propagated along the Mg-Zn reaction layer and Fe-Al phase, with little Mg-Zn reaction phases remaining on the steel side. As for noncoated steel, some remnants of the seam adhered to the steel substrate.     

输送带用钢丝绳生产及技术进步

介绍输送带用钢丝绳的主要生产控制及使用要求。从捻制质量、结构选择、力学性能以及粘合力和镀层质量控制等方面介绍输送带用钢丝绳的生产工艺控制以及各生产工序质量控制的注意事项,指出钢丝绳弯曲疲劳、输送带张紧装置造成胶带张力过大和张力分布不均匀、外力过大、腐蚀、异物损伤以及接头抽丝是输送带用钢丝绳使用过程中断裂的主要原因,保证钢丝绳储存质量和改善钢丝绳接头工艺有助于减少输送带生产过程中的钢丝绳消耗。对输送带用钢丝绳的技术进步做了展望。     

低氧铜杆线铜粉剥离原因分析及其对策措施

表面铜粉剥离,导致铜杆线表面损伤,其对铜杆线拉伸过程具有较大影响。通过扫描电镜分析,剥离铜粉厚度可达25μm,经物相分析确定其主要成分为铜及铜的氧化物。通过对剥离物和杆线表面缺陷进行形貌分析,以铜杆线的生产、加工各环节作为研究对象,并确认了铜杆轧制工艺、无酸清洗工艺、线表擦伤、拉伸角度及拉丝模具等5方面影响因素,制定了相应的对策措施。研究表明,铜杆氧化物剥落和机械损伤是铜粉剥离的主要原因,在铜杆线生产、加工环节,防止氧化物带入铜基体和避免铜线表面损伤能有效减少铜杆线铜粉剥离。     

热镀锌钢板生产概述 第二讲 热镀锌钢板及其发展（二）

镀锌层对钢铁制品有着良好的防护作用，对于钢板、钢丝、型钢、铸件等都可以用镀锌来进行防腐蚀。介绍了镀锌工艺的发展以及钢板的酰洗及溶剂种类等有关理论。     

RH喂硅钙线生产实践

RH喂硅钙线处理是武钢股份炼钢总厂二分厂2年多来使用较多的1种改善钢质的成熟工艺。生产实践表明,RH结束后喂硅钙线的收得率与喂线速度、喂线量、喂线钢种、喂线后的吹氩强度大小等有关;喂硅钙线应处理好增Si、增B、增N对钢种成分的影响,避免Si、B、N出格改钢;喂硅钙线能改变品种钢中夹杂物的形态,并提高轧后冲击韧性。     

Coatings by arc spraying of nanocrystalline metallic wires on carbon steel surfaces: surface hardness,hydrophobicity, and residual stress

Wire arc spraying of two different metallic wires composed of nanocrystalline and amorphous phases onto carbon steel sheets is carried out. Coating characteristics, including morphological and metallurgical changes, microhardness, residual stress, and surface hydrophobicity are examined using analytical tools. It is found that microhardness increases in the surface region of the coating because of oxidation and high cooling rates. Nanoparticles in the coating act like grain arresting centres contributing to higher residual stress levels. The surface texture of the coating, composed of micro/nanopores, enhances surface hydrophobicity. The coating produced by the 140MXC wire has higher surface hardness than that of the 95MXC wire, resulting in a correspondingly lower friction in the 140MXC wire. However, the residual stress formed in the coating is higher for 140MXC wire than that corresponding to 95MXC wire. In addition, both coatings produced by two different wire sprayings have similar hydrophobic characteristics at the surface.     

铜线高速拉拔过程数值模拟及质量控制

为了掌握铜线拉拔过程铜线的变形规律及其不同模具对拉拔过程的影响,通过对拉丝模具几何尺寸和铜线塑性变形的受力分析,建立拉拔变形模型并利用DEFORM-3D有限元对拉拔过程进行模拟,求解不同模角参数下铜线应力应变场和损伤场的变化规律,获得最佳的拉拔模角参数,减少模具磨损延长了模具寿命;同时分析了不同拉丝速度下铜线的变形规律,优化了拉丝工艺参数。     

品种钢连铸生产实践

邢钢引进奥钢联(VAI)技术建成的品种钢连铸机于2002年12投产。该铸机采用了结晶器电磁搅拌、液面自动控制、DYNAFLEX非正弦液压振动、DIAMOLD钻石结晶铜管、连续矫直等先进技术。在试生产阶段成功生产出冷镦钢、钢绞线、焊丝钢，取得了良好的生产和质量指标。     

热浸镀Zn-5%Al-RE合金钢丝镀层的表面形貌

本文采用金相显微镜、扫描电镜和能谱仪等设备分析了在Ｚｎ５％ ＡｌＲＥ合金溶液中热浸镀中碳钢丝表面的组织形貌和成分。通过与钢丝电镀锌和热镀锌的组织形貌对比、分析,我们发现：镀层中具有良好的过渡层组织是提高耐蚀性的根本原因。     

Advanced Process Possibilities in Friction Crush Welding of Aluminum,Steel, and Copper by Using an Additional Wire

Joining sheet metal can be problematic using traditional friction welding techniques. Friction crush welding (FCW) offers a high speed process which requires a simple edge preparation and can be applied to out-of-plane geometries. In this work, an implementation of FCW was employed using an additional wire to weld sheets of EN AW5754 H22, DC01, and Cu-DHP. The joint is formed by bringing together two sheet metal parts, introducing a wire into the weld zone and employing a rotating disk which is subject to an external force. The requirements of the welding preparation and the fundamental process variables are shown. Thermal measurements were taken which give evidence about the maximum temperature in the welding center and the temperature in the periphery of the sheet metals being joined. The high welding speed along with a relatively low heat input results in a minimal distortion of the sheet metal and marginal metallurgical changes in the parent material. In the steel specimens, this FCW implementation produces a fine grain microstructure, enhancing mechanical properties in the region of the weld. Aluminum and copper produced mean bond strengths of 77 and 69 pct to that of the parent material, respectively, whilst the steel demonstrated a strength of 98 pct. Using a wire offers the opportunity to use a higher-alloyed additional material and to precisely adjust the additional material volume appropriate for a given material alignment and thickness.     

铜包铝丝材的旋锻复合-拉拔成形与组织性能

采用"热旋锻-拉拔"方法制备了直径为φ65 μm、包覆铜层厚度较均匀、表面质量高和界面结合质量良好的铜包铝复合微丝,研究了合理热旋制度、热旋复合成形铜包铝线材的组织和界面结合状态以及中间退火和拉拔对线材组织与性能的影响.结果表明:合理的旋锻制度为旋锻温度350℃,单道次变形量40%,旋锻后形成了动态再结晶组织和厚度为0.7 μm的界面扩散层.复合线材的合理退火工艺参数为350℃/30 min (退火温度350℃、退火时间30 min),该条件下退火后线材延伸率达到最高值35.7%,界面扩散层厚度约为2.1 μm,退火后铜层和铝芯发生再结晶,组织内部形成等轴晶组织.当退火温度超过350℃时,铜层和铝芯晶粒长大,界面扩散层厚度增加,从而导致线材的延伸率下降.将单道次变形量控制在15%~20%,经过粗拉,制备了φ0.96 mm的丝材;粗拉后不进行退火处理,将单道次变形量控制在8%~15%,经过细拉,制备了表面光洁、直径为φ65 μm的复合微丝.在拉拔过程中,铜层和铝芯均出现〈111〉丝织构.      

废杂铜冶炼技术在铜线坯生产中的应用

介绍了世界上再生金属的生产、利用的历史现状和世界上先进的废铜冶炼生产技术。通过对四种不同生产工艺生产铜线坯对铜纯度要求的初步论述,确立了采取反射炉处理废杂铜,经有芯工频感应炉精炼后,生产电工用铜线坯是比较符合实际的生产工艺。本文着重介绍氧化还原反应处理废杂铜的工艺技术。