基于弱磁的钢丝绳探伤技术研究

依据磁荷分析理论,建立了钢丝绳断丝磁偶极子模型,计算了单丝断口处漏磁场的分布规律。采用正交设计方法对激磁回路参数进行了实验研究,确定了弱磁磁化系统的基本结构与基本参数,实现了磁化与检测的一体化设计。依据弱磁激励情况下钢丝绳缺欠处的漏磁场强度,选择了高灵敏度MR01型磁阻式传感器;给出了多种断丝形态的实测曲线。实验结果表明,基于MR01型磁阻式传感器的钢丝绳磁检测系统,不仅能够实现对小尺寸断口缺陷的有效检测,而且可用于剩磁检测,为钢丝绳探伤技术的发展提供了有价值的科学依据。     

三峡升船机钢丝绳断丝与磨损检测原理及实现

根据三峡升船机钢丝绳的使用特点，提出了三峡升船机钢丝绳检测的原理与方法，采用周向多回路对钢丝绳轴向励磁，利用漏磁场原理检测钢丝绳断丝，磁桥回路检测钢丝绳磨损量，并实现在一个传感器中对断丝和磨损两种缺陷信息的综合检测。在信号处理方面设计了相应的电路和软件，实现了缺陷的定量分析。     

Machine-vision-based electrode wear analysis for closed loop wire EDM process control

The purpose of this study was to develop a closed-loop machine vision system for wire electrical discharge machining (EDM) process control. Excessive wire wear leading to wire breakage is the primary cause of wire EDM process failures. Such process interruptions are undesirable because they affect cost efficiency, surface quality, and process sustainability. The developed system monitors wire wear using an image-processing algorithm and suggests parametric changes according to the severity of the wire wear. Microscopic images of the wire electrode coming out from the machining zone are fed to the system as raw images. In the proposed method, the images are pre-processed and enhanced to obtain a binary image that is used to compute the wire wear ratio (WWR). The input parameters that are adjusted to recover from the unstable conditions that cause excessive wire wear are pulse off time, servo voltage, and wire feed rate. The algorithm successfully predicted wire breakage events. In addition, the alternative parametric settings proposed by the control algorithm were successful in reducing the wire wear to safe limits, thereby preventing wire breakage interruptions.The full text can be downloaded at https://link.springer.com/article/10.1007/s40436-021-00373-y     

拔丝模孔形计算机视觉检测技术

拔丝模是拔丝工业中的重要零件，是控制拔丝精度的关键，目前一般用显微镜或投晾影仪检测孔形质量，检测精度低，速度慢，文中论述了用计算机视觉检测技术实现拔丝模孔形全自动测量的方法，作者依此完成了“拔丝模孔形自动测量仪”的研制与开发，研制出的仪器已交付天津市金刚石工具厂实际使用，实际应用结果表明，用视觉检测技术开发的“拔丝模孔形自动测量仪”测量精度满足实际要求，速度快，使用方便。     

Fabrication of alloy nanopowders by the electrical explosion of electrodeposited wires

Electrical wire explosion technique has been successful in the production of various pure metal powders. However, the process has the obvious limitation that alloy and intermetallic powders are difficult to produce due to the unavailability of their thin wire form. In this study, a novel method by which various alloys and compounds can be produced was suggested utilizing electrodeposition and wire explosion process. Al-Cu and Cu-Ni alloy nanopowders were fabricated by the electrical explosion of Cu-deposited Al and Ni wires. Ni-Cu nanopowders were composed of Ni- and Cu-solid solutions. Al-Cu wire explosion produced various phases in the order of Al, Al₂Cu, Al₃Cu₄ as the copper layer became thicker. It is demonstrated that the suggested method could provide means to produce numerous alloys and intermetallic nanopowders.     

H08Mn2Si盘条拉拔断丝原因分析

针对Ｈ０８Ｍｎ２Ｓｉ焊丝生产过程频繁断丝的现象,对断丝样品进行了断口扫描和金相工对相关的盘条件进行了理化检验分析。得出,盘条组织中的马氏体量较多是造成拉拔时步骤敏断丝的主要原因。‘     

金属丝材混丝的检测方法

根据金属的温差热电势原理，提出了金属织网中丝材混丝的检测方法，并运用ＴＰ－８０１单板机研制开发了微机混丝检测仪，可实现同时检测１６０根丝材。把该仪器用于织网的整经工序中，避免了网材的混丝事故。     

CCD扫描法拉丝模孔径测量仪

采用平行光投影法,以高精度线阵ＣＣＤ为测量传感器,结合机械扫描方法,完成对拉丝模孔径的快速检测。提出了ＣＣＤ孔径检测中抗暗斑干扰的电路设计,利用计算机误差修正技术提高了仪器精度。     

线型像质计线径检测方法的研究

像质计是测检测工业射线照片的射线照相灵敏度的标准器件,像质计线径是像质计的重要几何参数,线径值的准确度直接影响工业射线光机灵敏度。因此需要对像质计线径做出准确检测,通过分析给出2种像质计线径的检测方法。     

Analysis of the energy input during wire coating from a cylindrical magnetron source

In order to deposit thin films on a substrate several techniques can be used, e.g. chemical vapour deposition, atomic layer deposition or sputter deposition, depending on their specific advantages and disadvantages due to the related application. A significant parameter is the energy incident upon the substrate by the specific technique, especially when the heat capacitance of the substrate is low. Within this paper we analyse the energy transported into a thin wire (few 10 μm in diameter) during a dynamic inline aluminium sputter process in a cylindrical magnetron source. The evoked heating is important for the tensile strength of the wire and uniformity of the sputtered layer. Therefore, mathematical models were created to estimate the energy input into the wire supported by monte-carlo-simulations of the sputtering process using the TRIM-simulation (Transport and Range of Ions in Matter). Measurements with a Langmuir probe and the corresponding deposition rate were used to quantify these models, showing that at an aluminium coating process of a gold wire, the significant energy input is only due to electrons and ions of the processing gas (argon). Using the heat equation based on the sputtering apparatus' parameters, it was also possible to determine the energy input into the wire with in situ electrical resistance measurements. Both methods did show similar results, whereby the resistance results were more stable. The determined energy input made it possible to calculate the temperature profile during the wire-coating process which can be useful for estimations about film diffusion and process optimisation.     

Electrical Discharge Machining of MMCs Reinforced with Very Small Particles

This paper investigates material removal rate (MRR), kerf width, surface finish, and electrode wire wear for different pule-on-times as well as wire tensions during EDM of 6061 aluminum alloy reinforced with 10 vol % 700 nm SiCp MMC. Effects of pulse-on-time on output variables at lower and higher wire tensions were investigated. Similarly, effects of the wire tensions on output variables at shorter and longer pulse-on-times were also investigated. Longer pule-on-time increases the MRR though the higher wire tension reduces the MMR. The effect of wire tension on MRR is much more significant at longer pule-on-time compare to that at shorter pule-on-time. There is an optimum pule-on-time for which best surface finish is achieved. The surface finish deteriorates when the pulse-on-time is higher or lower than the optimum pule-on-time. With the rise of tension in wire, the surface roughness increases and decreases at shorter and longer pule-on-times, respectively. The machined surface contains solidified molten material, splash of materials, and blisters. Generation of the tapered slot with higher kerf width at the top indicates the wear of wire electrode. Significant variation of the electrode wire diameter was due to coating of the matrix, wear, and clogging of small reinforced particles in the electrode gap.     

金属筛超大网孔尺寸及超差比例的激光在线检测方法研究

介绍了金属筛超大网孔尺寸及超差比例的激光在线检测方法。检测是以激光一傅里叶频谱分析技术为基础,通过对金属筛频谱点的光强锐度分布进行概率统计分析而实现的。实验结果表明,该方法具有较高的检测精度和效率。     

Study on Prefire Phenomena of Wire Insulation at Microgravity

The experimental hardware was developed to perform the experiments of prefire characteristics of wire insulation caused by overload on board the SJ-8 China recoverable satellite. In the experiments, the prefire characteristics including the temperature and radiation characteristics of the wire insulations were presented. The temperature histories of the wire insulation in microgravity and the low-pressure environment in normal gravity were obtained. Effects of overloaded currents on the fire initiation were investigated for different wire coiled states. The results indicate that the natural convection almost vanished and the heat loss of the electric components decreased in the microgravity environment. It might cause overheating of the electric components and then results in fire, and thus the fire risks of wire in the microgravity condition are much more dangerous than that in normal gravity under the condition of overload.     

Surface Tensions and Thermal Conductivities of Aqueous LiBr-Based Solutions Containing n-Octanol and 2-Ethyl-1-Hexanol: Application to an Absorption Heat Pump

Surface tensions and thermal conductivities were measured for LiBr+1,3-propanediol+water and LiBr+LiI+1,3-propanediol+water. These two mixtures were chosen as one of the potential candidates for working fluids for absorption heat pumps. Surface tensions and thermal conductivities were measured by the capillary rise method equipped with a cathetometer and the transient hot wire method with a coated tantalum wire, respectively. The measured surface tension and thermal conductivity data were well correlated with a simple polynomial function of temperature and absorbent concentration. In addition, the surface tensions of LiBr+1,3-propanediol+water containing a small amount of alcohol-based surfactants, n-octanol and 2-ethyl-1-hexanol, were also measured at 298.15 K by the ring method. An increase in the surfactant concentration up to about 500 ppm leads to a gradual decrease in the mixture surface tensions.     

GXT型钢丝绳在线无损探伤仪工作原理

ＧＸＴ型钢丝绳在线无损探伤仪是采用漏磁交链原理研制成的。根据更换钢丝绳的依据和物理概念，建立了数学模型。结果表明，所建立的数学模型完全正确。     

热处理对镍钛合金丝材弯曲疲劳性能的影响

研究了热处理工艺对５０．６ａｔ％Ｎｉ－Ｔｉ合金丝材弯曲疲劳性能的影响。结果表明：该丝材经过固溶和时效后具有不同的弯曲疲劳寿命，其中固溶处理温度为１０２３Ｋ并且时效温度６７３Ｋ时，具有最高寿命；抗拉强度随热处理工艺的改变呈同样变化趋势。     

On the mechanics of wire cutting of cheese

The wire cutting process is used in the food industry during the manufacture and testing of products. The cutting process involves fracture as well as large strain deformation and surface friction. This paper investigates the mechanics of the wire cutting process of cheese through a combination of experiments, theory and finite element simulations. The experiments revealed that there was secondary damage on the cut surface, thus a higher fracture energy would be consumed than the common assumption of a single crack propagation. The numerical simulations showed that there was a six-fold change in the strain rate when wire diameters of 0.25  to 2 mm are used. This strain rate effect was modelled through a modification of a previous theoretical analysis of the wire cutting process. The numerical models were also used to predict the cutting forces using two failure criteria: critical strain, which was applied to the initiation of cracking, and a cohesive zone model to simulate crack propagation. Both criteria showed reasonable success in predicting the cutting forces, particularly for cuts made with small wire diameters.     

Investigation the parameters for torsion ductility of bead wire

Torsion testing is used to determine the quality of steel wire used for beads in pneumatic tires. However, strain aging (dynamic and static) caused by interstitial carbon and nitrogen atoms bound to mobile dislocations increases yield strength and decreases bead formability. Processing parameters of bead wire, such as line speed, lead bath temperature and wire diameter, were investigated, and theoretical calculations were made to estimate the effect of these parameters on strain aging. Nitrogen concentration was measured in bead wire samples with varying numbers of twists to failure during torsion testing. Surface morphologies of twisted bead wires were examined by scanning electron microscopy. Experimental data showed that torsional properties of bead wire were a function of stress relief temperature on and theoretical calculations showed that line speed and temperature have to be optimized for optimum torsion ductility.     

Fixed Abrasive Diamond Wire Saw Slicing of Single-Crystal Silicon Carbide Wafers

This article investigates the slicing of single-crystal silicon carbide (SiC) with a fixed abrasive diamond wire. A spool-to-spool rocking motion diamond wire saw machine using a 0.22 mm nominal diameter diamond wire with 20 µm average size diamond grit was used. The effect of wire downfeed speed on wafer surface roughness and subsurface damage was first investigated. The surface marks generated by loose diamond grit and stagnation of the wire during the change of the wire-cutting direction were studied. The use of scanning acoustic microscopy (SAcM) as a nondestructive evaluation method to identify the subsurface damage was explored. Effects of using a new diamond wire on cutting forces and surface roughness were also investigated. Scanning electron microscopy has been used to examine the machined surfaces and wire wear. This study demonstrated the feasibility of fixed abrasive diamond wire cutting of SiC wafers and the usage of a SAcM to examine the subsurface damage.     

On the bending of a stretched wire - case study of a tension measuring device

The case of a stretched wire bent successively over a system of three pulleys has been analysed with specific reference to a commonly used wire tension measuring device. With the help of the simple theory of elastic bending, expressions for the tension variation, angles of wrap, deflections etc., at the pulley have been obtained. A brief parametric study leads to some useful design guidelines. The analysis can be usefully applied to other systems also where wirelwire rope is bent over multiple pulleys.