维修和组装东风汽油机配气机构零件的方法

采用氧乙炔中性喷焊工艺，用含钴１０％的ＮＩ－ＣＶ－Ｂ－ＳＩ系列焊粉，采用一步喷焊法可修复磨损后的气门。在条件不允许的情况下，采用手工磨削气门座，同样可以保证气门和座的密封性，提高充气系数，减少进气阻力。     

真空练泥机螺旋喷焊强化研究

通过金相分析、及拉伸、剪切、磨损试验，研究了镍基自熔合金粉球喷焊层的组织结构和耐磨性能，并对真空练泥机螺旋磨损部位进行了喷焊强化，使螺旋的工作寿命提高了５倍。     

40Cr钢喷焊强化制造排气门研究

针对排气门材料短缺且不能满足日趋发展的发动机要求，提出用４０Ｃｒ钢喷焊强化代替俩排气门材料，并从强度，组织金相等多方面进行了可行性化证。对比试验及装车考核说明用４０Ｃｒ钢喷焊强化制造的排气门比现排气门寿命更长，能提高３倍以上。     

喷焊技术在气门修复中的应用

气门是汽车发动机上的关键零件,它在工作中要承受极高的冲击性交变载荷的作用,排气门还要受到高温、高压的影响。因此,有必要采取有效措施,对其工作表面进行强化处理,以延长其使用寿命。气门的喷焊,是一种利用热源产生的热能把自熔性合金粉末加热到熔化或半熔化状态,高速地喷射到经预处理过的气门密封面上,再经重熔形成强化喷焊层的强化、修复工艺。     

进口汽车桥间差速器的修复工艺

汽车桥间差速器常见故障是十字轴和行星齿轮内孔严重粘着磨损,造成桥间差速器传动失效。差速器的修复一定要满足必要的工艺技术条件。我们从一例进口的CXE187十五吨载货汽车桥间差速器的修复工艺实践中总结出了汽车桥间差速器修复的工艺要点。 1.十字轴的修复与检验 十字轴与行星齿轮配合表面由粘着磨损造成严重抓粘、烧伤的划痕,使配合失效。为恢复配合部位尺寸,我们采用了火焰喷焊法修复。喷焊前十字轴要认真清洗,用砂轮去掉磨损部位的氧化层和疲劳层,用水玻璃涂抹     

高铬铸铁喷焊粉末研究与应用

本文阐述一种高铬耐磨铸铁喷焊粉末的成分设计、组织状态、制粉过程、工艺性能、磨损试验、使用性能和工业性试验结果。代号为ＧＬ０１的合金粉末在工艺性能与使用性能方面优于中国常用的铁基喷焊粉末，且制造成本较低，有广阔应用前景。     

柴油机气门与气门座圈摩擦副磨损机理分析

采用台式试验装置模拟内燃机气门与气门座圈的负荷环境和接触条件,通过试验研究了气门与座圈的磨损机理以及气门与座圈磨损的主要影响因素。试验结果表明,气门与座圈的磨损主要来源于气门关闭时的落座冲击和燃烧压力作用下气门在座圈上的滑动,并且与气门的关闭速度、燃烧负荷、气门相对气门座圈的不对中性及气门和座圈的材料选择等工作状态有关。     

两用燃料发动机气门和气门座磨损研究

气门和气门座的磨耗试验是一种反映不同材质的气门和气门座配合时磨损情况的试验.针对长安汽车集团某4缸两用燃料发动机的气门和气门座进行了模拟磨耗试验.并根据试验结果选定方案4和方案8进行了台架和道路试验.结果表明,所选设计方案可有效避免产品过度磨损问题,同时找到了导致气门和气门座过度磨损的主要影响因素和相应的解决方法.     

利用振动信号诊断气门挺杆响故障

介绍了在EQ6 10 0发动机上模拟气门挺杆与导孔磨损后产生异响的试验结果。通过时域、频域分析法的分析比较 ,证明用振动技术可以诊断发动机的气门挺杆响故障。     

风机叶片喷焊强化工艺的研究

分析了风机叶片的磨损形式，认为其磨损是冲蚀和腐蚀共同作用的结果，通过试验含ＷＣ５０％的镍基喷支具有优良的抗磨性能。提出了“反变形法”、“喷底层”、“一二步中间”，保证了喷焊后的叶轮满足设计要求且具有可靠的耐磨性能，从而使风机叶轮的使用寿命提高了２－５倍。     

Application of the reverse 3D scanning method to evaluate the wear of forging tools divided on two selected areas

This study is focused on tools used in the industrial hot forging process of a front wheel forging (eventually–gear wheel) manufactured for the automotive industry. Four different variants were applied for the tools: 2 die inserts were coated with two different hybrid layers (GN + PVD type), i.e. AlCrTiN and AlCrTiSiN, one insert was only nitrided, and one was pad welded, to improve tool durability. The tool wear was analysed and represented by the material degradation on the working surface, based on the 3D scanning and the material growth of the periodically collected forgings. Additionally, the scanned tools were divided into two areas, in which it was found, based on the reliminary analysis, that various degradation mechanisms are predominant. Microstructural and hardness measurements of the analyzed tools were also performed. Based on the results, it was found that, in the central part of the die insert (area A), thermo-mechanical fatigue and wear occurred, while in the area of the bridge insert (area B), only abrasive wear could be observed. For these areas (A and B), the loss of material was determined separately. In area A for the inserts with hybrid layer GN+AlCrTiSiN and gas nitrided, an intensive increase of wear took place, which was not observed for the pad welded and GN+AlCrTiN layer insert, for which, together with the increase of the forging number, a proportional growth of the loss of material occurred. In area B the weakest results were obtained for the insert with GN+AlCrTiSiN layer, while wear of other die inserts grew similar and proportional.     

Field measurements of the evolution of wheel wear and vehicle dynamics for high-speed trains

This investigation demonstrates the wheel wear evolution and related vehicle dynamics of high-speed trains with an operating distance (OD) of around two million kilometres. A long-term experimental test lasting two years was conducted to record the wheel profiles and structural vibrations of various trainsets. The wheel wear, namely the profile shape, worn distribution and wheelset conicity, is investigated for several continuous reprofiling cycles. Typical results are illustrated for the stability analysis, and the ride quality is examined with increasing OD. In addition, the vibration transition characteristics between suspensions are investigated in both the time and frequency domains. The experiments show that the dominant wear concentrates on the nominal rolling radius, and the wear rate increases with OD because of the surface softening resulting from the loss of wheel material. The vibration of structural components is aggravated by the increase of the equivalent conicity of the wheelset, which rises approximately linearly with the wheel wear and OD. High-frequency vibrations arise in the bogie and car body related to the track arrangement and wheel out-of-roundness, causing the ride comfort to worsen significantly. Additionally, the system vibration characteristics are strongly dependent on the atmospheric temperature. Summaries and conclusions are obtained regarding the wheel wear and related vehicle dynamics of high-speed trains over long operating times and distances.     

镁合金微弧氧化陶瓷层结合强度与耐蚀性的研究

微弧氧化技术能够有效提高镁合金的耐蚀性。采用微弧氧化法在AZ91D镁合金表面原位生长一层陶瓷层,利用电子显微镜、盐雾试验等研究了该陶瓷层的结合强度和耐蚀性。结果表明,在恒流条件下,随着微弧氧化时间的增加,陶瓷层的厚度增加、层内缺陷增多、致密性下降,陶瓷层的结合强度和耐蚀性均呈现先增大后减小的趋势。     

Rail vehicle wheel wear prediction: a comparison between analytical and experimental approaches

There are a number of theoretical and practical techniques to compute rail vehicle wheel wear. For instance, the Archard equation is a well-known tool to determine the worn volume in sliding contact, as a function of normal load, sliding distance and the surface hardness. Of course, the wear coefficient (called K) used in this equation to differentiate the wear models implicitly comprises the conditions that govern the contact surface. Two situations can be taken into account when considering a sliding contact in a rail vehicle wheels, particularly along a curved track: (i) when the radial force prevails the lateral tangential force, which is mainly the frictional force but before flanging and (ii) during flange contact. Also, the Archard equation is employed within the tread and flange regions separately, both the regions being of interest in this paper. A number of approaches are then used to find the distance slid. The authors compare the field test results and the outcome of the analytical approaches. When the wheel wear results acquired from the two test bogies on Iranian Railways, all technical (rigid frame bogies with new assemblies and components) and operational items were identical, except for changing the bogie orientation in the second test trial for a short period. Good agreement was found between the analytical and practical investigations.     

纯电动汽车轮胎磨损关键影响因素研究

木文在分析纯电动车汽车不同于传统燃油车对于轮胎磨损关键因素的基础上,对纯电动车汽车轮胎磨损影响因素进行了试验验证。试验针对栽荷及动力系统两个因素采用控制单一变量法进行轮胎道路磨损试验,并通过对试验路线优化及驾驶员驾驶习惯的约束,使得测试结果更加准确及客观。最后对测试完成之后的轮胎花纹形态、轮胎花纹深度及轮胎预计里程寿命进行了详细数据分析。     

现代发动机气门座圈材料的发展

阐述了气门座圈的工作环境和磨损机理，高品质气门座圈的关键在于恰当的材料选择和零件的合理设计，在材料选择时必须考虑材料的物理性质和机械性能，由于粉末冶金材料具有成形尺寸精度高，合金选用和烧结后处理工艺灵活以及明显节约原材料、工时和能源等优点；因此与其它材料相比具有明显的竞争力，在内燃机中得到了日益广泛的应用，我国ATP公司（中日美合资安庆帝伯粉末冶金有限公司）引进国外先进的粉末冶金材料和制备技术，研制并开发了多种具有高热硬度和高耐磨性的气门座圈，适用于高强化的汽油机、柴油机和某些代用燃料发动机。     

The effect of worn profile on wear progress of rail vehicle steel wheels over curved tracks

Dynamic performance, safety and maintenance costs of railway vehicles strongly depend on wheelset dynamics and particularly on the design of wheelset profile. This paper considers the effect of worn wheel profile on vehicle dynamics and the trend of wear in the wheels as a result of the vehicle movements. ADAMS/RAIL is used to build a multi-body system model of the vehicle. The track model is also configured as an elastic body. Measured new and worn wheel profiles are used to provide boundary conditions for the wheel/rail contacts. The fleet velocity profile taken during its normal braking is also used for the simulation. Wear numbers are calculated for different sets of wheels and the results compared with each other. Outcome of this research can be used for modifying dynamic performance of the vehicle, improving its suspension elements and increasing ride quality. It can also be further processed to reach to a modified wheel profile suitable for the fleet/track combination and for improved maintenance of the wheels. A major advantage of the computer models in this paper is the insertion of the wheel surface properties into the boundary conditions for dynamic modelling of the fleet. This is performed by regularly measuring the worn wheel profiles during their service life and by the calculation of the wear rate for individual wheels.     

Effects of diesel fuel characteristics on spray and combustion in a diesel engine

Fuel properties play a dominant role in the spray, mixture formation and combustion process, and are a key to emission control and efficiency optimization. This paper deals with the influence of the fuel properties on the spray and combustion characteristics in a high-pressure and temperature chamber. Light diesel fuel spray and combustion images were taken by using a high-speed video camera and analyzed by their penetration and evaporation characteristics in comparison with current diesel fuel. Then, a single-cylinder DI engine was used to investigate combustion and exhaust characteristics. The mixture formation of the light diesel fuel is faster than that of the current fuel depending on physical properties like boiling point, density, viscosity and surface tension. Engine test results show that smoke is reduced without an increase in other emissions.     

汽车发动机气缸热喷涂涂层的现状与发展

为了提高汽车发动机气缸壁热喷涂涂层的耐磨性能并降低燃料消耗,系统分析了该涂层的失效机制,综述了汽车发动机铝合金气缸壁耐磨涂层、气缸盖内表面以及活塞端面耐热涂层的热喷涂制备及发展现状,指出通过优化喷涂工艺提高涂层中固体润滑剂含量有助于提高涂层耐磨性,而通过喷涂制备合理结构的梯度涂层有助于提高耐热涂层的寿命。提出通过控制涂层中孔隙及其分布来改善涂层储油能力,通过原位形成具有自润滑功能的氧化物来改善涂层减摩性能,以及通过适当提高基体温度改善粒子间结合来提高涂层抗粒子剥落磨损性能将是该类涂层进一步发展的主要方向。