Wear mechanisms in a nonrotating wire rope

A nonrotating wire rope used in mine hoist operations is being examined by the U.S. Bureau of Mines to determine operative wear mechanisms. Typically, bending and loading the ropes during service cause small, localized movements at interwire contacts, leading to material loss through wear: The cumulative effect of both material loss by wear and wire breakage by fatigue failure accelerates rope retirement. If the macroscopic mechanics of wire rope failure are to be understood, microscopic deformation and degradation processes must be identified and quantified. As a first step in this study, interwire wear and deformation were studied using a combination of scanning electron microscopy and hardness measurements. Both fretting and abrasive wear were identified as wear mechanisms. Preferential sites for fretting and abrasive wear were identified and are discussed regarding rope construction and geometry and the tribo-system.     

钢丝绳疲劳的磁记忆检测系统

模拟钢丝绳的弯曲疲劳状态，运用金属磁记忆技术对钢丝绳表面的磁场分布进行检测，并对其磁场强度的变化进行了分析和比较。试验结果表明。磁记忆检测方法能有效用于钢丝绳应力集中和疲劳损伤的早期诊断，对防止事故发生具有重要的现实意义。     

汽车起重机钢丝绳的断裂原因

某建筑工地的汽车起重机在起吊钢筋材料时，连接副钩的钢丝绳发生了断裂。通过宏观分析、尺寸测量、破断力拉伸试验、金相分析、扫描电镜形貌观察及能谱分析等，对钢丝绳断裂原因进行了分析。分析认为：汽车起重机钢丝绳外层钢丝存在严重磨损、局部存在集中断丝及开裂，局部断丝数量已超出GB/T 5972—2016标准报废基准，导致钢丝绳局部承载能力不足而发生断裂。     

汽车起重机钢丝绳的断裂原因

某建筑工地的汽车起重机在起吊钢筋材料时,连接副钩的钢丝绳发生了断裂.通过宏观分析、尺寸测量、破断力拉伸试验、金相分析、扫描电镜形貌观察及能谱分析等,对钢丝绳断裂原因进行了分析.分析认为:汽车起重机钢丝绳外层钢丝存在严重磨损、局部存在集中断丝及开裂,局部断丝数量已超出GB/T 5972-2016标准报废基准,导致钢丝绳局...     

Corrosion behaviour of steel ropes for snow and rockfall barriers

Abstract

During service, steel ropes can suffer from corrosion, which can reduce their mechanical properties. This degradation is particularly important in the case of structural ropes, or barriers, for snow and rockfall protection because it is not easy to detect any significant degradation over time due to the locations of these structures, which are often difficult to reach. Moreover, rockfall barriers are frequently used in marine environments to reduce the instability of rocks and cliffs, where corrosive attack by chlorides can be very dangerous. This study has characterised the effects on corrosion of the geometrical configurations of the strands and wires in the ropes, and the benefits of zinc and zinc alloy protective coatings on the wires for reducing the degradation of structural ropes. The aim of the research was to obtain information useful for the design of high durability barriers and the selection of an appropriate rope and coating. An approach based on an electrochemical testing has been compared with one based on classical tests involving the exposure of ropes in aggressive environments (salt spray, humidity chamber, etc.) in order to find an electrochemical method able to distinguish the performance of different materials as well as to monitor the corrosion degradation of barriers in the field.

Using electrochemical techniques it was possible to quantify the corrosion rate and demonstrate the better behaviour of ropes coated with zinc–aluminum alloys in comparison with pure zinc. Moreover it was possible to evaluate the actual reactive area, and therefore the protective geometry effect when comparing two ropes with different geometries. This approach should be extended to further kinds of ropes in order to improve basic corrosion understanding of this important structural component.     

塔式起重机钢丝绳断裂分析

通过宏观检查并结合体式显微镜SM、直读光谱仪OES、金相显微镜OM、扫描电子显微镜SEM等检测分析仪器,对一条断裂的塔式起重机钢丝绳进行失效分析。结果表明:钢丝绳上存在大量陈旧断口,同时在钢丝绳上发现了不同程度的挤压磨损。这些损伤的存在造成整条钢丝绳的承载力严重下降,在使用过程中,剩余钢丝不足以承受所加载荷,最终发生断裂。建议在以后的起吊作业过程中,定期对钢丝绳进行检查,及时更换不满足使用要求的钢丝绳;钢丝绳使用过程中采取合理的润滑方法进行维护;钢丝绳在保存或者转运过程中,应避免损伤。     

矿井提升钢丝绳磨损原因的分析

钢丝绳是矿井提升设备以及井下牵引轨道运输设备的重要组成部分,是连接容器和传递动力的重要部件.钢丝绳的损坏不仅对提升运输的安全构成威胁,也会导致钢丝绳的使用寿命大大缩短,增加了生产成本.将现场采集的斜井提升钢丝绳上的油垢制成粉末试样进行XRF射线分析,将多个磨损部位制成金相试样进行扫描电镜分析,得出钢丝绳受磨损的种类,提出了必要的预防措施.     

原位合成Al_3Ti颗粒增强铝基复合涂层(英文)

以直径200μm、纯度99.5%的钛丝丝网为反应源,通过熔渗-原位反应法制备一种Al3Ti金属间化合物颗粒增强铝基表面复合涂层。差热分析结果表明,在890°C下,Ti丝和Al熔体间发生反应。采用XRD、SEM以及显微硬度和磨损测试对所得到的复合涂层进行表征。结果表明:当保温时间为20min时,钛丝反应完全,原位合成为块状和条状的Al3Ti颗粒;颗粒的显微硬度大约为基体显微硬度的4.5倍;在载荷10N的干滑动磨损条件下,与没有增强的Al基体相比较,保温20min所制备的复合涂层表现出较好的耐磨性,其磨损机制为粘着磨损和磨粒磨损共存。     

多绳摩擦提升机首绳快速更换装置仿真研究

介绍一种多绳摩擦提升机首绳快速更换装置,分析其机械部件的组成、现场布局及工作原理,将其用Solid-Works建模并导入ADAMS软件,模拟实际工程换绳过程,分析其运动特征。通过动力学仿真得出装置铰接点的力变化情况,为后续的有限元分析提供了重要的力学依据。     

Sliding Wear Properties of HVOF Thermally Sprayed Nylon-11 and Nylon-11/Ceramic Composites on Steel

Polymer and polymer/ceramic composite coatings were produced by ball-milling 60 μm Nylon-11 together with nominal 10 vol.% of nano and multiscale ceramic reinforcements and by HVOF spraying these composite feedstocks onto steel substrates to produce semicrystalline micron and nanoscale reinforced polymer matrix composites. Room temperature dry sliding wear performance of pure Nylon-11, Nylon-11 reinforced with 7 nm silica, and multiscale Nylon-11/silica composite coatings incorporating 7-40 nm and 10 μm ceramic particles were characterized using a pin-on-disk tribometer. Coefficient of friction and wear rate were determined as a function of applied load and coating composition. Surface profilometry and scanning electron microscopy were used to characterize and analyze the coatings and wear scars. The pure Nylon-11 coating experienced less wear than the composites due to the occurrence of two additional wear mechanisms: abrasive and fatigue wear. This article is an invited paper selected from presentations at the 2007 International Thermal Spray Conference and has been expanded from the original presentation. It is simultaneously published in Global Coating Solutions, Proceedings of the 2007 International Thermal Spray Conference, Beijing, China, May 14-16, 2007, Basil R. Marple, Margaret M. Hyland, Yuk-Chiu Lau, Chang-Jiu Li, Rogerio S. Lima, and Ghislain Montavon, Ed., ASM International, Materials Park, OH, 2007.     

钢丝绳定量无损检测现状

钢丝绳无损检测的目的是保证钢丝绳的安全运行，并在安全运行的前提下尽量减少因过早报废而产生的浪费。对目前主流的钢丝绳无损检测方法的检测原理及特点进行分析比较，给出各种方法的研究现状和实践效果，包括20世纪90年代以后提出的新检测方法，如磁致伸缩法和声发射一超声法。最后讨论目前钢丝绳定量无损检测面临的问题。     

High temperature wear resistance and thermal fatigue behavior of Stellite-6/WC coatings produced by laser cladding with Co-coated WC powder

The Stellite-6/WC composite coatings were produced on AISI H13 hot work tool steel by laser cladding with mixture of Co-coated WC (WC-12Co) particles and Stellite-6 powder. The phase composition, microstructural characterization, high temperature wear resistance and thermal fatigue behavior of Stellite-6/WC coatings were investigated and compared with the properties of the coatings produced from mixture of WC particles and Stellite-6 powder. The results showed that using the WC-12Co particles alleviated the decomposition of WC and resulted in the weaker intensity of W₂C, CoC_x and Co₆W₆C peaks in the X-Ray Diffraction (XRD) patterns. Compared with using the WC particles directly as the coating material, using the WC-12Co particles could further improve the wear resistance of coatings according to the relative lower width and depth of wear scars at the same WC content. In addition, fewer fatigue cracks were observed on the surface of coatings made by adding WC-12Co particles under the same thermal fatigue conditions, which indicates that using WC-12Co is beneficial to extend the life of Stellite-6/WC coatings.     

钛合金自冲铆接头微动磨损机理及疲劳性能

对钛合金同种TA1-TA1（TT）及异种TA1-Al5052（TA）,TA1-H62（TH）自冲铆接头进行疲劳试验,用扫描电子显微镜对断口及微动区进行观测研究其微动磨损机理,并研究下板强度对接头疲劳寿命和失效形式的影响.结果表明,断口裂纹萌生区即为微动磨损区.微动磨损导致微动区亚表面产生微裂纹并逐步扩展为宏观疲劳裂纹导致接头最终失效;微动磨屑在微动磨损过程中主要起减轻磨损作用.总体上TT接头具有最优疲劳性能,疲劳载荷较高时TA接头疲劳性能优异,疲劳载荷较低时TH接头疲劳性能优异.两板强度相当且疲劳载荷较高时失效形式主要为铆钉断裂,疲劳载荷较低时失效形式主要为下板断裂;而下板强度与上板强度相差较大时,疲劳失效形式为下板断裂.     

起重机钢丝绳的疲劳可靠性设计

指出了两种传统钢丝绳设计计算方法的弊端。根据起重机钢丝绳失效主要是金属疲劳的原理 ,采用应力 -强度干涉模型 ,对起重机钢丝绳进行了疲劳可靠性设计。通过实例计算 ,得出了钢丝绳所需直径大小 ,并与两种传统设计方法得出的结果进行比较 ,可以看出 ,疲劳可靠性设计方法更为符合实际     

A356铝合金微弧氧化膜微动磨损行为的研究

采用微弧氧化（MAO）在A356铝合金表面制备MAO膜,利用球-平面接触在SRV-V微动摩擦磨损机上探究变载荷和位移下微弧氧化对A356微动磨损机理的影响。结果表明：MAO膜由疏松层和致密层构成,其均匀性、致密性和结合力良好。MAO膜的摩擦系数、磨损率均低于A356,MAO膜减摩耐磨性较好。随位移增加MAO膜的摩擦耗散能系数低于A356,MAO膜能提升A356微动磨损过程的稳定性。载荷增加时A356磨损机制为磨粒磨损-粘着磨损,伴随犁削和疲劳剥层; MAO膜磨损机制为磨粒磨损-粘着磨损和疲劳剥落。位移增加时A356磨损机制为粘着磨损和疲劳剥落,伴随微犁削;MAO膜磨损机制为粘着磨损和疲劳剥层-粘着磨损和磨粒磨损。A356的磨痕内聚集Fe、O元素,存在材料转移和氧化磨损;MAO膜磨痕内聚集Fe元素,存在材料转移。     

表面纳米化对低碳钢擦磨损性能的影响

用表面机械碱研磨对低碳钢板材进行表面处理,经X射线衍射及透射电镜分析表明,处理后的样品上已形成了纳米结构表层,用往复式摩擦实验机研究了处理后样品的摩擦磨损性能。结果表明其摩擦系数较未处理样品明显降低,其磨损量在低载荷及中等载荷作用下也较未处理样品降低,磨痕形貌的扫描电镜观察表明,表面纳米化能减弱低碳钢的疲劳磨损效应,提高材料的摩擦磨损性能。     

DZ2车轴钢离子渗氮层的冲击磨损损伤演变研究

为解决变轨距高速列车转向架轮轴花键配合面承受动载时的冲击磨损问题,对DZ2车轴钢进行离子渗氮强化处理。采用一系列宏/微观方法表征离子渗氮表层相结构、表面形貌、显微组织及硬度梯度,并对渗氮层及调质态基体的冲击磨损动力学响应及损伤行为进行研究。结果表明:两类状态的试样抗冲击磨损性能差异显著,在相同冲击动能下,离子渗氮层的能量吸收率低于调质态材料,DZ2车轴钢离子渗氮后比原始调质态具有更好的耐冲击磨损性能。DZ2调质态材料以剥层磨损为主,接触区域摩擦氧化显著;离子渗氮表面损伤轻微,仅局部材料磨损剥落,摩擦氧化现象不明显。随冲击周次的提高,调质态材料磨损损伤加剧,损伤区域出现大量表面微裂纹和氧化磨屑堆积,而经离子渗氮处理材料损伤较轻微,冲击磨损表面未观察到裂纹萌生。离子渗氮工艺能有效增强变轨距车轴的抗冲击磨损性能。     

Effect of Microstructural Variation on Dry Sliding Wear Behavior of Ti-6Al-4V Alloy

The present article evaluates the influence of independent control factors such as microstructural variation, normal load, sliding velocity, and test duration on dry sliding wear behavior of Ti-6Al-4V alloy at room temperature using a statistical approach. Ti-6Al-4V alloy has been heat treated in a controlled manner in order to produce different microstructural features (i.e., lamellar, bimodal, and equiaxed). Lamellar microstructure is found to be harder than bimodal microstructure followed by equiaxed microstructure in Ti-6Al-4V alloy. Dry sliding wear tests have been carried out using a multiple Tribo tester following a well planned experimental schedule based on Taguchi’s L₉ orthogonal array design. Dry sliding wear behavior of Ti-6Al-4V alloy consisting of various microstructural features is related to their hardness values. Results indicated that lamellar microstructure has the lowest sliding wear resistance followed by bimodal and equiaxed microstructure. With the help of signal-to-noise ratios, optimal combination of control factors to minimize the dry sliding wear in Ti-6Al-4V alloy has been determined. Normal load is the most significant control factor influencing the dry sliding wear behavior of investigated Ti-6Al-4V alloy followed by sliding velocity, test duration, and microstructural variation. Normal load has greater static influence of 27.02%, sliding velocity has an influence of 18.07%, test duration has an influence of 12.71%, and microstructural variation has an influence of 10.55% on weight loss of Ti-6Al-4V alloy due to wear having R ² = 0.89. Two wear mechanisms have been identified: oxidative wear occurs at the lowest sliding velocity and delamination wear occurs at the highest sliding velocity. Optical microscopy, scanning electron microscopy, energy dispersive x-ray spectroscopy, and Rockwell hardness measurements have been used to characterize the microstructures in order to correlate the results obtained.     

等离子喷涂层磨损 / 接触疲劳失效行为研究现状

综述了国内外学者对等离子喷涂层磨损/接触疲劳失效行为研究的现状,指出单一地研究接触疲劳失效或摩擦磨损失效存在一定的局限性,滚动/滑动竞争性失效研究对工程实践具有持久性的指导作用,是未来等离子喷涂层磨损/接触疲劳失效行为研究的重要方向。