合成绝缘子的超声检测方法

提出以临界角入射的纵波检测合成绝缘子横截面上裂纹。在模拟绝缘子芯棒的断裂过程中，用超声探测裂纹的大小和扩展速度来评价绝缘子的质量和各类材料绝缘子的承载能力，从而研究合成绝缘子可能发生的内绝缘故障以及发展机理。阐述了超声检测的理论依据，试验结果说明该方法可用于检测合成绝缘子芯棒裂纹。     

复合绝缘子超声检测系统的研制

为消除硅橡胶复合绝缘子缺陷对电网安全运行造成的隐患,在对超声检测原理研究的基础上提出采用识别相位差异与幅值差异的方法来检测是否存在缺陷,并介绍了复合绝缘子超声检测系统研制过程中的各关键技术环节。经过实际运行证明,该系统能快速可靠地检测出复合绝缘子护套与芯棒界面间的内部缺陷,具有检测结果直观、判别准确和可视化成像等优点。     

涡流检测在制备NbTi/Cu六方单芯棒中的应用

利用涡流检测技术可以检测NbTi/Cu六方单芯棒表面铜层中的缺陷。采用外穿过式差动线圈检测方法,对NbTi/Cu六方单芯棒实现涡流探伤。结果表明,涡流检测方法能够有效检测出六方单芯棒表面铜层中存在的夹杂、面上压伤及磕伤等缺陷,保证了单芯棒的质量。涡流检测方法有利于控制超导线材的质量。     

面向Ti-6Al-4V合金的开缝芯棒孔挤压强化次数研究

为了探究挤压强化次数对开缝芯棒性能的影响，实现孔挤压强化工具的可重复使用，分析了开缝芯棒孔挤压强化工艺，开展了开缝芯棒20次孔挤压强化Ti-6Al-4V合金试验，研究了挤压强化次数对开缝芯棒孔挤压强化效果的影响。结果表明，开缝芯棒20次孔挤压强化过程中，挤压力、工作环直径和孔结构孔径波动平缓，未发生显著变化；开缝芯棒的挤压部位存在划痕，工作环直径与孔结构孔径的变化在加工误差范围内；开缝芯棒的划痕对Ti-6Al-4V合金孔结构挤压强化效果影响不大，开缝芯棒孔挤压强化能够实现孔挤压强化工具的重复使用。     

基于随机振动响应谐振频率偏移的绝缘子无损检测方法

针对电力系统绝缘子安全检测需要,提出一种基于随机振动响应谐振频率偏移的绝缘子无损检测方法。利用Abaqus有限元仿真软件,进行了绝缘子振动模态和随机振动响应分析。根据支柱陶瓷绝缘子断裂位置多发生在其上下法兰附近的实际情况,对无缺陷绝缘子和上、下法兰区有裂纹绝缘子的随机振动响应进行了数值仿真和检测试验研究。结果表明,可以通过绝缘子随机振动响应的谐振频率偏移进行绝缘子无损检测,即上部法兰区的裂纹会导致谐振频率向高频偏移,而底部法兰区的裂纹会导致谐振频率向低频段偏移。在此基础上,通过数值仿真研究了裂纹深度对谐振频率偏移的影响。     

冷轧管机芯棒断裂检测方法

提出了冷轧管机芯棒断裂可靠的检测方法，该检测系统灵敏度高，抗干扰能力强，对非铁磁性材质管材芯棒的断裂检测非常简便。     

MPM连轧机速率制度的探讨

研究了影响限动芯棒连轧机速度制度的有关因素，定量 限动速度与芯棒预插行程、芯棒规格和荒管长度之间的关系，并分析了影响连轧机速度制度的关键因素－－－机架孔型系数。     

电网绝缘子的无损检测技术

介绍国内外电网绝缘子无损检测的现状，包括产品的出厂质量控制以及挂网后的无损检测方法，指出目前无损检测技术在绝缘子检测中存在的问题，并展望了发展方向。     

拉力芯棒在二辊斜轧延伸中的应用

介绍了在二辊斜轧延伸中采用拉力芯棒轧制的新工艺。探讨了拉力芯棒轧制与固定芯棒轧制、浮动芯棒轧制和限动芯棒轧制相比所显示的优越性。实践表明，采用拉力芯棒轧制方式，可以轧制薄壁管，提高产品尺寸精度和内表面质量。     

科技动态

延长长芯棒使用寿命的方法据俄刊报道,乌克兰钢管工业联合公司的专家对俄罗斯伏尔加钢管厂Φ426mm限动芯棒连轧管机的长芯棒使用寿命进行了研究。研究认为,过去为了提高长芯棒的使用寿命,芯棒基体材料采用含Cr、V、Mo、Si等合金元素的钢制作,并在芯棒表面镀铬。对由外国公司提供的芯棒使用寿命的分析和研究表明,镀铬芯棒虽可减小磨损,但在使用过程中会在芯棒上出现深度达2cm的纵向裂纹,这样深度的裂纹会使芯棒报废。对在轧制过程中造成芯棒使用寿命缩短的各种芯棒表面缺陷产生的原因和发展机理进行了分析研究。研究表明,在没有镀铬层的地…     

先进CNC复合加工刀具和复合切削技术

介绍了德国、日本、意大利等国生产的先进的CNC复合加工刀具的特点与应用范围,阐明了CNC复合切削技术必要的硬软件及期望达到的效果,并提出今后CNC复合加工技术发展方向.     

SiC表面活化对Ni-Co-P/SiC复合沉积层性能的影响

用JSM－35CF型扫描电镜观察和分析了Ni-Co-P/SiC复合沉积层，对其中的复合相微粒SiC作表面活化预处理后参与化学沉积。结果表明，经表面活化后的SiC颗粒与Ni-Co-P基质相的结合变得较紧密，复合沉积层的孔隙率降低，在一定程度上改善了复合沉积层复合相粒子周边存在孔洞的问题。     

Mechanical properties of tungsten fiber reinforced ZrAlNiCuSi metallic glass matrix composite

Tungsten fiber reinforced (Zr₅₅Al₁₀Ni₅Cu₃₀)_98.5Si_1.5 metallic glass composites were fabricated and characterized. The mechanical properties of the composite under compression and tension were investigated. Tungsten reinforcement greatly increased compressive strain to failure compared to the unreinforced (Zr₅₅Al₁₀Ni₅Cu₃₀)_98.5Si_1.5 metallic glass. The compressive failure mode changed from a single shear band to multiple shear bands and to localized fiber buckling and tilting as the volume fraction of tungsten fiber increased. The maximum tensile strength and strain to failure of each of the composites were lower than those of unreinforced material due to the lack of substantial shear bands. Tensile toughness changed to some extent due to different interface reactions. The reason for the improved mechanical properties is discussed.     

复合磷酸盐改性水玻璃砂的研究

本文研究了复合磷酸盐改性水玻璃粘结剂的制备及其型砂的混碾工艺和性能。试验结果表明,在水玻璃中加入磷酸盐、有机物K,提高了型砂的常温强度,降低了高温残强,改善了水玻璃砂的溃散性。     

陶瓷树脂内衬复合钢管介绍

采用树脂材料密暑离心铝热法制备陶瓷瓷钢管内衬层气孔，从而获得具有防护耐磨双重功能的复合管材。产品内衬层与钢管基体结合强度高，可在真空状态下长期运行，在高温下内初不鼓泡、不折皱。     

铂复合电极研究进展

铂复合电极是通过适当的工艺将铂复合在钛、钽、铌等基体上.主要介绍了铂复合电极的主要复合方法及应用领域.水溶液电镀和冶金复合是目前最常用的制备铂复合电极的方法.此外,铂电极复合方法还有熔盐电镀,磁控溅射,化学气相沉积等,指出了各种方法的优缺点及发展方向.铂复合电极强度高,耐腐蚀性、导电性好,催化活性高,主要应用于阴极保护、电析金属、离子水制备等领域中.     

金刚石复合镀层的研究现状

综述了化学复合镀、复合电沉积法制备金刚石复合镀层的研究现状。阐述了复合镀层制备的机理。应用及制备中存在的主要问题，并为今后的研究提出了建议。     

Laser-based repair of carbon fiber reinforced plastics

The recent progress in laser system technology enables innovative techniques for machining of carbon fiber reinforced plastics (CFRPs). A representative application is the layer-by-layer removal of damaged composite material to provide a cavity for refilling with repair plies. Results show that it is possible to achieve a reliable and automatable removal rate to perform arbitrary repair cavity geometries, obtaining a relevant time-reduction with respect to the conventional manual grinding process. The combination of modern UV-laser sources with a scanning technology enabling deflection speeds up to 2 m/s, suppresses heat affected zones (HAZs) and detachment of fibers from the polymer matrix. A method for the selective removal of surface matrix without damaging the fibers beneath is also presented.     

Experimental investigation of embedding high strength reinforcements in extrusion profiles

Embedding reinforcement or functional wires in extruded profiles offers the potential to increase mechanical properties as well as the field of application. With improved strength and stiffness and an integrated function as deformation sensor or data transmitter the weight of space frame structures can be reduced substantially. To comprehend the general conditions when embedding the reinforcement and functional elements during the extrusion process, experimental extrusion investigations have been carried out for the analysis of significant process and tool geometry parameters.Extrusion with porthole dies, i.e. by feeding the elements over bridges inside the die in the aluminum base material flow, was studied to manufacture continuous reinforced, thin-walled, and hollow profiles. Special care was taken to ensure an accurate positioning in the transient material flow to prevent a loss of functionality by insufficient covering and loss of positioning caused by the die geometry or unequal temperature distribution inside the die. Studies on different reinforcement wires and wire ropes based on high strength steel are presented, showing an increasing process stability when using solid wires. General process restrictions are analyzed and process guidelines are presented based on exemplary extrusions.     

Surface characteristics of machined aluminium metal matrix composites

This paper investigates the effect of cutting parameters and particulate properties (volume fraction and average particulate size) on the microhardness variations of the aluminium matrix beneath the machined surface. Orthogonal cutting tests were carried out on different aluminium matrix composites reinforced with varying volume fractions and average sizes of alumina particulates. Characterization of the machined subsurface was made using optical, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The metallographic analysis revealed severely damaged machined subsurface with numerous geometrical defects and plastically deformed aluminium matrix. This study also yielded some interesting findings on the influence of particulate volume fraction and average size in altering the microhardness in the aluminium matrix. The lower the reinforcement volume fraction and the coarser the particulates, the higher are the variations in matrix microhardness. The microhardness measurements on the aluminium matrix beneath the machined layer showed higher values when machining under wet conditions with reduced depth of plastically deformed zone.