运用堆焊工艺修复铝电解多功能天车轨道局部压溃

分析铝电解多功能天车轨道接头局部压溃的原因，介绍采用手工堆焊工艺修复方案之全过程。     

天车啃轨的原因及防范措施

天车啃轨是指行走机构在运行过程中,轮缘与轨道侧面相互摩擦,导致车轮与轨道磨损。在天车使用过程中,由于车轮啃轨问题的严重性,会造成运行过程中阻力增大,从而导致轨道、车轮、减速机、电机、接触器等电气元件使用寿命缩短。因此,啃轨问题不仅影响设备使用寿命,同时还增减设备的维护成本,严重时会引发安全事故。     

电解多功能天车轨道的改进与实践

电解多功能天车轨道由于使用多年以及设计安装中存在的问题，运行状况较差，轨道变形造成天车主梁、端梁、大轮振动，并磨损、破坏严重。通过分析轨道现状，提出轨道改进方案，并在实践中取得成功。     

天车轨道焊接安全防护装置设计

对天车轨道断裂接口检修焊接作业,改善天车轨道断裂接口焊接作业安全防护,设计制作一种天车轨道焊接安全防护装置提出建议,能够解决天车避免停机影响生产工作效率,排除检修过程安全隐患,提高检修轨道焊接的安全可靠性,满足机组现场生产的要求等问题。     

焙烧多功能天车啃轨原因分析

列举焙烧多功能天车常见的啃轨现象,从轨道、车轮和日常操作规范等方面进行分析,提出改善焙烧多功能天车车轮啃轨的建议,以确保焙烧多功能天车的安全平稳运行。     

新型柔性轨道固定系统在铝电解多功能天车中的应用

传统轨道固定系统日益明显的轨道磨损变形、轨道梁破裂弯曲、轨道固定系统失效等弊端对铝电解多功能天车的运行和铝电解车间的生产管理造成很大的影响。为了解决上述问题,通过借鉴现代化港口重载起重机固定系统的成功经验,某公司成功将新型柔性轨道固定系统应用于某电解车间,并对其概况、主要施工工艺及安装进行介绍。新型柔性轨道固定系统应用后,取得了较好的效果,消除了轨道伸缩缝,延长了轨道和轨道梁的使用寿命,避免了常见的固定系统失效问题,缩短了压板的供货周期,提高了施工效率。     

轨道梁天车新驱动方案的研究与开发

较详细地论述了采用直线感应电动机驱动 ,用轨道梁兼作次级的天车新方案、结构及工作原理。首次提出中间驱动方式 ,能较好地解决轨道梁产生的挠度、边缘效应等对机械和电气性能的影响。它较老式旋转电动机驱动方案具有优势 ,并在未来轨道梁天车驱动方面的应用前景广阔     

多功能天车大车行走轮啃轨的分析

多功能天车啃轨是大车在轨道上相对歪斜运行到某一限度后出现的问题,本文就多功能天车啃轨形成的原因及啃轨的测量和调整,进行重点分析。     

系统危险控制技术在栈桥监控中的应用

原料厂中和工段天车栈桥由于受地基的影响，栈桥松动产生摆动，轨道变形，构成天车出轨这一危险。本文应用系统危险控制技术，采用工程对策、控制对策、教育训练对策来加强栈桥监控、控制了危险的发生，保证了天车安全运行。     

精整跨天车啃轨轨道标高误差分析与调整

分析了安钢二炼钢精整跨天车啃轨、轨道标高误差产生的原因及产生的后果，通过调整为该跨天车安全顺行带来明显效果。     

Tribological properties of aluminum alloy matrix TiB2 composite prepared by in situ processing

An investigation of the wear behavior, in lubricated sliding and rolling of in situ prepared TiB₂ particle-reinforced 2024 T4 Al alloy matrix composites against 52100 steel and hardened pearlitic nodular cast iron, respectively, was undertaken. In sliding contact, the 10 vol pct 0.3-μm TiB₂-metal matrix composite (MMC) showed slightly less wear than the 10 vol pct 1.3-μm TiB₂-MMC. Transmission electron microscopy of cross sections, taken normal to the wear track and parallel to the sliding direction, revealed that the TiB₂ particles on the wear track were polished and particle pullout was largely absent. This was attributed to the strong interfacial bonding between the Al-alloy matrix and the TiB₂ reinforcing phase. The TiB₂ particles on the wear track inhibited spalling. Subsurface damage of the MMC did not occur. The wear of the steel mating surfaces worn against the TiB₂-MMCs was minor and caused by the cutting action of the TiB₂ particles that resided on the MMC wear track. In rolling contact, the 0.3-μm-size TiB₂-MMC showed 5 times higher weight loss than the 1.3-μm TiB₂-MMC for the same content of reinforcement, but the weight loss of the cast iron mating surface was less for the former. For the smaller particle size, the wear of 5 and 10 vol pct TiB₂-MMCs was the same. A high density of surface cracks was present on the wear track of the 0.3-μm TiB₂-MMC but not on the 1.3-μm MMC. The significance of strong particle/matrix interfacial bonding and particle size effect on the wear behavior of ceramic particulate-reinforced MMCs in lubricated sliding and rolling wear is discussed.     

Effects of daily topical fluoride gels on resin composite degradation and wear

OBJECTIVES: This in vitro study compares the effects of professional and consumer-applied topical fluorides on the weight, wear resistance and surface appearance of a resin composite containing barium boroaluminosilicate glass filler particles. METHODS: Prior to wear studies with a pin and disc apparatus, specimens were immersed for 6 min 10 times in water, three consumer-applied topical fluorides (1.1% NaF, 0.4% SnF2, or 0.5% APF gel) or a professionally applied topical fluoride (1.23% APF gel). Specimens were weighed before and after each immersion. Following wear studies, the specimen surfaces were visually evaluated using scanning electron microscopy. Weight changes were analyzed for significant differences using one-way ANOVA and Duncan's multiple range test (p = 0.01). Values of wear parameters were ranked and tested for significance using one-way ANOVA with least squares mean contrast (p = 0.05). RESULTS: Significant differences were found in the weight loss of specimens treated with different fluoride agents: 1.23% APF = 0.5% APF > 0.4% SnF2 > 1.1% NaF = water (p < or = 0.0001). Significant differences in initial wear depth (S(i)) occurred in the following samples: 1.23% APF > 1.1% NaF = 0.5% APF (p = 0.04). Scanning electron micrographs showed variable wear tracks on the specimen surfaces. The specimen surfaces outside the wear track were smooth for those treated with water or with NaF; the surfaces outside the wear track of specimens treated with APF showed extensive loss of filler particles. SIGNIFICANCE: Topical APF agents caused extensive loss of filler from the resin composite specimens whereas 1.1% NaF caused the least damage. Although significant differences in surface wear resistance were detected, clinical studies are needed to determine the effect of topical fluorides on the properties of this resin composite.     

宏观摩擦仪器引起不确定度的分析处理

在摩擦学中,摩擦系数与磨损率都是通过实验得到的,本文的工作旨在研究与这两个参数估算相关的测量不确定度。文中特别采用了一个标准的销-盘摩擦计,其上的两个销固定在同一端面。针对不同的负载、滑动距离和测试时间,总共进行了20次测试,测试时环境温度和相对湿度需保持恒定,测试后使用触针式轮廓仪来获得磁盘截面的磨损疤痕剖面,通过测量磨损痕迹截面及平均磨损体积得到磨损率。实验结果表明,载荷测量时的不确定度对摩擦系数和磨损率的评估有很大的影响,所获得的信息对于优化实验装置和/或开发适当的程序以降低测量不确定度是十分有用的。     

门式起重机小车啃轨的故障分析与解决措施

分析门式起重机小车啃轨是造成车轮磨损严重、轴承损坏频繁的主要原因,并采取具体措施。     

API套管圆螺纹接头粘扣失效分析

粘扣是套管接头的失效形式之一，它发生在套管上扣操作过程中的螺纹处。套管一旦发生粘扣，直接影响到套管柱的密封性能和连接强度。通过对套管接头的上卸扣实验和接头螺 凶数值计算，对套管产生粘扣的原因进行了研究，并利用摩擦磨损机理，描述了粘扣的产生过程。     

Wall Stud-to-Track Gap: Experimental Investigation

Because of an increasing interest in the use of cold-formed steel for commercial and residential framing, both design and installation guidelines are needed. The wall framing, which typically consists of axial load bearing C-section studs, is laterally braced and attached at the bottom and top of the wall to a track section. The common bottom and top attachment consists of the wall stud and track of nominally the same cross-section depth. Because the nominal depths of the C-section and the track are similar, a tight connection is often not achieved and a gap occurs. The Standard for Cold-Formed Steel Framing—General Provisions specifies that the gap between the wall stud and track in a wall assembly must not exceed 1/8?in. This gap dimension is consistent with the gap specified by ASTM C 1007. The value of 1/8?in. is based on industry experience and practice but had not been experimentally verified. To explore both the stud-to-track connection strength and the aesthetic concerns associated with a gap between the axial load bearing stud and the track in a typical cold-formed steel wall assembly, a test program was initiated at the University of Missouri-Rolla. Based on the findings of the 54 wall assembly tests and short column tests performed in this experimental study, design guidelines are proposed for a typical wall stud assembly.     

Al靶溅射功率对CrAlN涂层组织结构及摩擦性能的影响

为探寻Al靶功率对CrAlN涂层性能的直接影响, 利用直流反应磁控溅射的方法在304不锈钢基体上沉积CrAlN涂层, 并研究不同Al靶功率对CrAlN涂层组织结构与摩擦性能的影响.采用SEM、XRD、AFM、往复摩擦磨损试验机、显微硬度计、三维轮廓仪对试样的物相组成、表面形貌、摩擦磨损性能、硬度和磨痕形貌进行表征.结果表明:随着Al靶功率的增加, CrAlN涂层的晶粒尺寸呈现轻微的先增大后减小的规律, Al靶功率为180 W时的晶粒尺寸最小; 随着Al靶功率的增加, 显微硬度、平均沉积速率呈现先增大后减小的规律而磨痕深度、平均体积磨损率呈现出相反的变化趋势.经综合比较, Al靶功率为150 W时CrAlN涂层的综合性能较优.      

AlCrN/硅系陶瓷在大气、海水环境下的摩擦学性能

采用多弧离子镀技术在316L不锈钢基底上沉积AlCrN涂层.通过扫描电子显微镜（SEM）、X射线衍射仪(XRD)、纳米压痕仪等分析测试手段,对镀层的形貌、成分、相结构、硬度等进行表征,并利用摩擦磨损实验机Rtec考察AlCrN/陶瓷（Si₃N₄、SiC）在大气、海水环境下的摩擦学性能.结果表明:在大气、海水环境下,AlCrN/SiC的摩擦系数和磨损率都远小于AlCrN/Si₃N₄;SiC球表面的微观凹坑对氧化膜SiO₂起到收纳作用,同时减少磨粒磨损.较之于Si₃N₄陶瓷配副,AlCrN涂层与SiC陶瓷对磨时表现出更为优异的摩擦学性能.      

应用铁谱技术分析龙门刨床导轨磨损原因

本对B2020A／1龙门刨床V型导轨面局部磨损故障产生的原因，应用铁谱技术进行了详细分析。实现了在不解体情况下的预知维修，为机械设备中不封闭滑动导轨易产生磨损故障的判断分析提供了理论和实践实例。     

Can wear in total hip arthroplasties be assessed from radiographs?

The validity of wear measurements from total-hip radiographs was assessed using a wear simulator which consisted of a total hip prosthesis mounted on a Plexiglas orientation jig. Wear was mesured by a micrometer device and uni- and duoradiographic methods of wear measurement were used with a variety of acetabular cup orientations. In the initial calibration studies the duoradiographic technique proved to be more accurate. The source of the inaccuracies of the uniradiographic method was determined analytically by means of a geometrical model. Forty-inch or 72' source-to-object film-distances provided similar accuracy and the errors in wear measurement varied from --0.1 +/- 0.4 mm (2 S.D.) to 0 +/- 0.9 mm for wear magnitudes of 1 and 5 mm respectively, regardless of cup position. In subsequent calibration studies the previous radiographs were compiled to represent seven hypothetical patients at various stages of follow-up whose prostheses exhibited between 1 and 5 mm wear. Clinicians assessed the degree of wear, using both the uni- and duoradiographic techniques, under supervision but unaware of the true position and orientation of the wear track. The resulting errors were of the same order as the wear magnitudes being measured. The location of the measurements on the radiographs was then restricted to approximately the true wear axis but again the errors were so large that it was still impossible to make any valid wear assessments. The calibration runs were therefore terminated at this point and it was concluded that wear measurements could not be made from clinical radiographs.