燃油泵滑动轴承摩擦副材料试验研究

船舶燃油泵滑动轴承在贫油及介质中含有大量杂质的状态下易出现故障,利用磨损试验,通过改变轴瓦材料和轴颈表面处理工艺,分析轴承对异物的包容性、嵌藏性和自润滑性能.结果表明,合适轴瓦材料和轴颈表面处理工艺,可降低轴瓦的磨损,提高燃油泵滑动轴承工作的可靠性.     

提速客货车用改性氟塑料-金属复合衬套材料的试验研究

用纳米氧化锌作为填充剂，通过机械搅拌和超声振荡处理，制备了纳米氧化锌改性聚四氟乙烯材料，并对改性后的氟塑料与金属复合研制的衬套的摩擦磨损性能变化的机理进行了分析。结果表明，各项性能均达到或超过了标准规定的技术要求，为该衬套在提速客货车中的应用奠定了基础．     

金属弯曲试验时测定真实弯曲应力的理论与方法

金属弯曲试验是生产及科研中常用的一种力学试验方法.试样所承受的弯曲应力一般按弹性范围内的公式来计算.但当试样在弯曲试验中产生塑性变形时,则按弹性公式计算的弯曲应力必然偏高,以此来确定材料的抗弯性能是不合理的.金属在弹塑性状态内真实规定非比例弯曲应力σ_(tpb)(试样外侧表面的非比例弯曲应变达     

轴瓦套张开位移的有限元计算

汽轮机在运行过程中,轴推压轴瓦套,使轴瓦套中产生应力和应变,在上下轴瓦套之间产生的一定的张开量.采用ABAQUS软件,建立有限元物理模型,对实际工况进行仿真,计算出上下轴瓦套之间的张开量,并进行应力分析,确定该工况下所产生的张开量是符合要求的.在建立有限元模型过程中,充分考虑轴瓦与轴、轴瓦与螺栓以及上下轴瓦套之间的接触效应,螺栓的联接和螺栓预紧力的作用.     

磁弹性法在测量高速客车车轴表面残余应力中的应用

磁弹性法是一种快速、简便的表面残余应力无损检测技术。它利用Ｂａｒｋｈａｕｓｅｎ Ｎｏｉｓｅ（巴氏噪声）的强度与材料的内应力呈现单调关系，从而由巴氏噪声的强度来测量表面残余应力。本文介绍了磁弹性法测定构件表面残余应力的基本原理、测试方法及其在高速客车空心车轴表面滚压强化后，在车轴表面残余应力测量中的应用。     

最终退火后的晶粒尺寸对锡青铜波纹管滞弹性的影响

滞弹性是衡量金属波纹管性能的一个重要指标,它不仅与材料的原子间结合力有关,而且还与材料的组织状态有关。国外对测量弹性元件的滞弹性和热处理后的机械性能及组织状态提出了相应的技术要求,国内一些生产厂家虽然对弹性元件的弹性模量、刚度和晶粒尺寸有一定要求,但没有统一的标准,本文的目的在于通过实验,找出锡青铜Q_(Sn65-01)和Q_(Sn4-03)波纹管管坯的最终退火晶粒尺寸对其滞弹性的影响。     

陶瓷/金属功能梯度多层组合板的热弹性极限分析

对陶瓷／金属功能梯度多层组合板进行了稳态热传导分析及热弹性极限分析，导出了稳态温度分布场，极限状态热弹性应力分布的计算式，并在弹性极限状态下，得到了弹性极限温度．文中的结果是以ZrO2／Ti-6Al-4V陶瓷热障涂层为对象得到的，其模型和方法同样适用于各类金属陶瓷梯度涂层材料．     

金属在弹性应力长期作用下的永久变形机理

分析了金属在常温状态受弹性应力作用时微量塑性变形的机理，从变形积累的角度出发进一步分析了金属结构在长期弹性载荷下国产生宏观永久变形而失效的原因。     

GY—50镶嵌型水工轴瓦的试验研究

介绍了一种ＧＹ－５０镶嵌型固液自润滑的新型水工轴瓦，并对其在重载低速下的摩擦特性进行了试验，证明它是一种较理想的水工轴瓦。     

铝冷轧加工表面的微裂纹分析

微乳液润滑的铝冷轧过程中常会在铝合金表面出现与轧制方向垂直的规则微裂纹．规则裂纹的产生是由于新生金属表层氧化膜与体相金属具有不同的拉伸性能．考虑氧化膜拉伸强度极限与其厚度、体相材料的屈服极限及边界润滑的摩擦系数等因素,建立了理论模型,预测微裂纹分布间隔．通过对两种不同轧机冷轧加工后的铝合金表面分析,验证了分析模型的正确性,研究结果将对铝冷轧特性的分析起到促进作用．     

Investigation on mechanism of the improvement in tribological properties of carbon fiber reinforced polytetrafluoroethylene composites by surface treatment

Tribological properties of polytetrafluoroethylene (PTFE) composites filled with differently surface treated carbon fibers (CF), sliding against GCr15 steel under dry sliding conditions, were investigated on a block-on-ring M-2000 tribometer. Experimental results reveal that rare earths (RE) surface treatment reduces the friction and wear of CF-reinforced PTFE (CF/PTFE) composites. Scanning electron microscopy (SEM) investigation of worn surfaces of CF/PTFE composites shows that cracks or pores are visible on the worn surfaces of untreated and air-oxidated composite, while no crack and very few pores present on the worn surface of REtreated composite. The fiber-friction-angling effect makes carbon fibers angled and oriented along the frictional shearing force, and finally parallel to the friction surface, which makes interfacial adhesion become a key factor to tribological properties of CF/PTFE composite. With strong interfacial adhesion between carbon fiber and PTFE after RE surface treatment, carbon fibers are not easily detachable from the PTFE matrix in the process of fiber-friction-angling, which prevents the rubbing-off of PTFE, and accordingly improves the friction and wear properties of the composite.     

Tribological behavior of polytetrafluoroethylene coatings based on LY12 substrates in the space environment

The spacecraft space radiation environment was simulated by60 Co source. The polytetrafluoroethylene(PTFE) coatings were fabricated on LY12 substrates. And the effect of gamma(γ) irradiation on the tribological behavior of PTFE coatings under vacuum conditions was investigated. Results indicate that the radiation dose has insignificant effect on the friction coefficient of PTFE coatings, and the wear of PTFE coatings reduces with the increase of gamma dose. As the gamma dose was 100 kGy, the friction coefficient of the PTFE coatings first increased with the increase of sliding velocity and then decreased, and the wear of the PTFE coatings decreased with the increase of sliding speed. As the gamma dose was 100 kGy, the friction coefficient of the PTFE coatings first decreased with the increase of load and then increased, and the wear rate of PTFE coatings increased with the increase of load. Scanning electron microscope was utilized.     

顶推滑移法下沉钢套箱施工技术

以沙田赣江特大桥主墩双壁钢套箱下沉施工为背景,介绍了顶推滑移法下沉钢套箱施工总体技术方案。即在陆地滑道上拼组钢套箱首节,待首节拼组完毕后,利用顶推系统将钢套箱顶推至水中滑道上,此时利用提升梁升降功能,实现水中滑道变坡,使首节部分进入水中,然后再在千斤顶的顶推作用下,将钢套箱完全滑入水中;将首节浮运至墩位处,进行接高、下沉及吸砂、封底作业。对施工过程中所涉及的滑移轨道、提升梁、顶推系统、捆绑浮箱、防溜和防倾覆等关键设备、关键结构、关键措施进行了详细的计算分析,提供了详实的理论依据。该施工技术投入设备少、施工效率高、可流水化作业,取得了良好的经济效益和社会效益。     

TiN涂层的滑动磨损特性

研究了 3Cr2 W8V基体离子镀 Ti N涂层的滑动磨损特性。分析了涂层的磨损机理。结果表明 :Ti N涂层的耐磨性明显高于 3Cr2 W8V基体。涂层的主要磨损机制为磨粒磨损和疲劳剥落。当试验载荷从 4 90 N到 980 N时 ,涂层的磨损率上升 ,而从 980 N上升到 1 4 70 N时 ,各涂层的磨损率下降 ,其原因是磨损机制发生了变化 ,前者以磨粒损为主 ,氧化磨损为辅 ;而后者以氧化磨损为主。     

钢管混凝土拱桥中钢管与混凝土剪切滑移分析

目前钢管混凝土拱桥虽然建设了不少,但在钢管混凝土的剪切滑移的研究和认识方面还存在一定的不足,该文对短期静力荷载作用下的钢管与混凝土界面接触进行了研究,建立了节段模型,对剪切滑移的ANSYS实体模型进行了介绍,并分析了两相邻吊杆间的单肢拱肋的时间历程响应曲线,得出了荷载从初始加载至达到极限承载力时拱肋位移的变化规律及各主要阶段的接触状态。     

Experimental study on frictional and sealing performances of packing rings in an oil-free gas compressor

To enhance the reliability and to extend service life of packing rings, tribological and sealing performances are investigated based on the experimental results. Friction force, leakage rate and power consumption of three materials of pressure packing seals are measured in a refitted vertical gas compressor. The rings are made of common filled polytetrafluroethylene (Filled PTFE), PTFE reinforced with 30% mass fraction carbon fiber (30%CF+PTFE), and carbon-carbon composites infiltrated with PTFE (C/C+PTFE), respectively. It is found that packing rings will periodically vibrate with the periodic vibration of pressure packing after the travel direction of motion abruptly turns to the reverse direction. Furthermore, the amplitude of vibration slows down with the increasing crank angle. Approximate value of friction force is available by multiple-point fast Fourier transformation (FFT) employed to process the experimental results by reducing the impact of vibration to a great extent. Of three materials of rings employed in experiments, Filled PTFE presents minimal leakage rate accompanied with maximum power consumption. And 30%CF+PTFE exhibits minimum friction power and moderate leakage rate. As for C/C+PTFE, its high mechanical and thermal properties are favorable factors to enhance the ability of operating under high pressure and velocity and to improve the wear resistance. Unfortunately, this also leads to a large leakage rate. Comprehensive consideration should be taken into to evaluate the availability, reliability and service life for a type of packing ring under dry running conditions.     

镍—钼—磷／聚四氟乙烯复合电沉积工艺研究

在镍－钼－磷（Ni-Mo-P)合金电镀液中加入聚四氟乙烯（PTFE）制得了镍－钼－磷／聚四氟乙烯（Ni-Mo-P/PTFE)复合镀层。研究了镀液主要成份及工艺条件对复合镀层的影响，优选出一种较佳的工艺条件及复合镀液配方。由复合镀层性能测试结果发现，与Ni-Mo-P合金相比，由于PTFE的加入，提高了复合镀层的减摩性，但结合力与硬度略有下降。     

Dry sliding wear behavior of silver containing Ni-based composite-steel tribo-pair

Ni-based self lubricating composites containing four different amounts of silver were prepared by powder metallurgy (PM) route. The room temperature friction and wear behavior was investigated by carrying out dry sliding experiments against bearing steel using a ring-on-disk configuration. Tests were conducted at a constant load of 100N and different sliding speeds of 0.5, 1.0 and 1.5 m/s to analyze the effect of both the speed and the silver content on the wear behavior of the tribo-pair. The friction coefficient and the wear rate of the composites were found to decrease with increasing both the sliding speed and the silver content. The wear rate of the counterface was observed to be a little higher when it was siding against the composite having silver in comparison to that without any silver. However, the overall wear rate of the tribo-pair was found to decrease with increasing sliding speed and silver content.     

80m单线铁路钢桁梁拖拉法架设技术

合埠铁路跨越蚌埠地区到发场的上（下）行联络线特大桥设计有1孔80m单线钢桁梁,为减少对到发场的运营影响、保证行车安全,采用在钢桁梁的一端搭设钢支墩拼装钢桁梁,之后再纵向拖拉就位的施工方法。详细介绍了临时支墩和拼梁支架的设计与搭设、钢桁梁滑道系统连续上滑道和间断下滑道的结构组成、导梁的设计与安装和拖拉设备的构成与实施等。对同类工程施工具有借鉴意义。     

密封用填充改性PTFE的研究及应用

PTFE(聚四氟乙烯)的填充改性是近年来研究较多的项目。本文介绍了采用模压烧结工艺制备玻璃纤维和石墨改性的PTFE动态密封材料,并对其拉伸强度、压缩回弹性能和摩擦、磨损性能及耐磨机理做了系统的研究分析,结果表明,该密封材料具备较好的抗拉强度、优异的压缩回弹性能和较好的耐磨损性能,可用于对耐磨耗性、耐温性能要求较高的动态密封场合,具有广阔的应用前景。