某城际动车组在正线运行时因黏着降低出现滑行,施加紧急制动停车后,04车3,4轴的5,6,7,8位轮对踏面出现不同程度擦伤.文章详细分析了轮对擦伤的原因并实现了故障复现,确定轮对擦伤原因为车组在持续严重滑行时,04车制动系统仅能实现1次持续排风功能,使本架参考速度无法正常恢复到车组速度,导致防滑功效降低.针对上述问题,提出改善车组在严重滑行时的持续排风功能和缩短电制动切除时间的解决方案,并通过了试验验证.

文章介绍了我国首款通过欧洲TSI认证、出口到北马其顿、适应低站台的时速160 km铰接式动车组的整体结构、总体性能参数和型式试验,以及电气系统、转向架、制动系统、车体等主要系统及部件的结构、性能和技术特征,总结了适应低站台的铰接式动车组的特点,并提出了其平台化拓展方向.

为了解决某城际动车组正线运行时司机显示器无网压、主断路器自动跳开故障,文章分析了高压检测电路的原理及熔断器的工作特性,确定了故障的原因,并提出了相应的优化方案.试验验证和运用考核结果显示,优化后的动车组有效降低了过分相时高压电压互感器单个绕组中的涌流,提高了高压检测电路的可靠性.

随着城市化的进程,城轨交通客流强度不断增大,发车间隔不断压缩,使得我国城轨交通呈现出快速、重载、智能的发展趋势.文章结合我国目前城轨车辆快速、重载的发展状况,提出城轨车辆最大轴重的概念和建议值,且应按最大轴重对承载结构件进行设计,详细分析了城轨车辆结构件的技术发展特征,并建议应及时检测和维护车轮和钢轨,降低车、轨的振动和噪声,以提高车、轨的综合使用寿命.

采用扫描电镜(SEM)、透射电镜(TEM)、电子背散射技术(EBSD)、能谱仪(EDS)和拉伸测试等手段,研究快速冷冲及再结晶退火对喷射成形快速凝固细晶Al-Cu-Mg合金微观组织和力学性能的影响.结果表明:细晶Al-Cu-Mg合金在快速冷冲及再结晶退火过程中析出相主要以平衡相S相为主,还有少量较粗的Al 6 Mn相,随着变形道次的增加,析出相的密度不断增大、尺寸显著减小.快速冷冲引入的缺陷有助于Al-Cu-Mg合金脱溶和再结晶形核,促进S相和再结晶的形核与长大,从而有效细化晶粒、获得均匀纳米晶组织和促进S相弥散分布.快速冷冲Al-Cu-Mg合金的主要强韧化机制是细晶强化和析出强化,经4道次快速冷冲后合金的极限抗拉强度和伸长率分别达578MPa和17.5％,与1道次快速冷冲合金试样的相比较,极限抗拉强度提高48.5％,伸长率提高44.6％.

采用喷射成形技术制备7A04铝合金及玄武岩颗粒增强7A04铝合金复合材料,利用金相显微镜(OM)、透射电镜(TEM)、扫描电镜(SEM)和能谱(EDS)分析复合材料微观组织和界面结构,对比研究复合材料的力学性能.结果表明:玄武岩颗粒在铝基体中弥散分布,并与铝基体形成强力结合界面,玄武岩颗粒边缘的SiO2不断被反应生成的 Al2O3取代,形成一层几十纳米厚度的高温反应层,反应生成的 Al2O3强化玄武岩颗粒与铝基体的结合界面;弥散分布的玄武岩颗粒促进基体中位错增殖、空位形成和析出相的析出,析出相主要以板状的η(MgZn2)相和亮白色条状或椭球状的T(Al2Mg3Zn3)相为主,结合界面、高位错密度及弥散分布的第二相显著提高复合材料的力学性能,添加玄武岩颗粒的7A04铝合金复合材料的屈服强度和极限拉伸强度分别达667 MPa 和696 MPa,与未添加玄武岩颗粒的7A04铝合金相比分别提高10.4％和10.1％.

文章阐述了四空气弹簧铰接式动车组转向架的技术特点、主要技术参数,以及构架、悬挂系统、牵引装置等零部件的主要结构特征.此外,本文还针对该转向架的牵引装置的载荷工况和相关车辆的动力学性能进行了重点讨论和评估.

Transmission electron microscopy (TEM), electron backscattered diffraction imaging (EBSD) and X-ray diffractometry were used to analyze the microstructure and texture characteristics of Al−9.8Mg−1.5Li−0.4Mn alloy cross-rolled and extruded plates, and the tensile properties and deep drawing performance were measured. The results show that the occurrence of dynamic recrystallization was promoted, the grains were refined and the preferred orientation of the recrystallized grains was improved by large strain cross rolling. Compared with CBA and CCB rolling methods, CBB rolling method significantly reduced the orientation density of the typical Brass texture {110}〈112〉 in the extruded plates. The orientation densities of Copper texture {112}〈111〉 and Brass texture {110}〈112〉 on the β orientation line in the CBB rolled plates were the lowest, and there were no typical texture features in the plates. Meanwhile, better deep drawing could be gained in the CBB rolled plates, and the mechanical properties of the 0°, 45° and 90° directions were basically the same. The tensile strength, yield strength and elongation at room temperature for the CBB rolled plates were 617 MPa, 523 MPa and over 20.1%, respectively. The deviation of the mechanical properties at different directions was less than 3%.

The microstructure evolution of spray formed and rapidly solidified Al-Cu-Mg alloy with fine grains during rapid cold punching and recrystallization annealing was investigated by transmission electron microscopy (TEM). The results show that the precipitates of fine-grained Al-Cu-Mg alloy during rapid cold punching and recrystallization annealing mainly consist of S phase and a small amount of coarse Al6Mn phase. With the increase of deformation passes, the density of precipitates increases, the size of precipitates decreases significantly, and the deformation and transition bands disappear gradually. In addition, the grains are refined and tend to be uniform. Defects introduced by rapid cold punching contribute to the precipitation and recrystallization, and promote nucleation and growth of S phase and recrystallization. Deformation and transition bands in the coarse grains transform into deformation-induced grain boundary during the deformation and recrystallization, which refine grains, obtain uniform nanocrystalline structure and promote homogeneous distribution of S phase.

High-resolution transmission electron microscopy (TEM), X-ray diffractometry (XRD), energy dispersive spectroscopy (EDS) and hardness test were used to study the re-dissolution and re-precipitation behavior of nano-precipitates of the spray-formed fine-grained Al−Cu−Mg alloy during rapid cold stamping deformation. Results show that the extruded Al−Cu−Mg alloy undergoes obvious re-dissolution and re-precipitation during the rapid cold-stamping deformation process. The plastic θ′ phase has a slower re-dissolution rate than the brittle S′ phase. The long strip-shaped S′ phases and the acicular θ′ phases in Al−Cu−Mg alloy after three passes of cold stamping basically re-dissolved to form a supersaturated solid solution. A large number of fine granular balance θ phases precipitate after four passes of rapid cold-stamping deformation. Rapid cold stamping deformation causes the S′ phase and θ′ phase to break and promote the nano-precipitate phases to re-dissolve. The high distortion free energy of the matrix promotes the precipitation of the equilibrium θ phase, and the hardness of the alloy obviously increases from HB 55 to HB 125 after the rapid cold stamping process.

High-resolution transmission electron microscopy, energy dispersive spectroscopy, and hardness test were used to study the nano-precipitates and evolution of nano-precipitation of the sprayformed fine-grained Al-Cu-Mg alloy during rapid cold stamping deformation. Results show that the elongated S-phase and the acicular ' phase of the Al-Cu-Mg alloy after three passes of cold stamping of rapid cold-shock deformation undergoes re-dissolution, and a large number of the fine granular balance  phases are precipitated after four passes of rapid cold-stamping deformation. The main mechanism of low-temperature re-dissolution of S' phase and ' phase in Al-Cu-Mg alloy induced by rapid cold stamping deformation is the precipitation phase fracture, grain boundary diffusion, and vacancy diffusion. The change in the hardness of the alloy during rapid cold stamping deformation is affected by the combination of phase-resolving softening, work hardening, and reprecipitation strengthening and increases at three stages. The hardness increases from 55 HB to 125 HB, which is increased by 127%.

提出了一种以轮轨蠕滑温升为目标,车辆动力学性能为约束条件的机车车轮踏面优化方法,并通过数值算例分析了影响轮轨摩擦温升的主要因素,表明轮轨接触斑形态与轮轨蠕滑温升及接触应力呈正相关,减小轮轨接触斑纵轴长度能够明显减小轮轨蠕滑温升,缓解车轮踏面剥离.

精确的速度预测控制是实现高速动车组安全、准点、节能优化控制的基础.然而,高速动车组运行过程干扰因素多、动力学非线性复杂,难以通过数学分析的方式建立其精确的速度预测模型.文章充分利用回声状态网络在非线性时间序列预测方面的优势,进行高速动车组运行速度的在线预测,同时采用多目标粒子群优化算法对预测控制输入进行多目标优化,实现高速动车组运行速度的精确控制,并基于某型号高速动车组的现场运行数据,仿真验证了本文方法的有效性.

阐述HXD1型机车车轮不圆度状态.对4种干线HXD1型机车超过4000个车轮进行不圆度测试.基于现场试验获得的大量数据探讨制动系统、制动控制方式和车轮镟修定位方式对车轮多边形的影响.研究结果表明,HXD1 、HXD1C型机车车轮存在 17～19阶多边形磨耗,HXD1B、HXD1D型机车车轮主要以偏心磨损为主.HXD1型机车车轮多边形与制动系统和制动控制方式关系不大,与车轮镟修时的定位方式关系较大.

The number of rolling bearings used in railway rolling stock and their application status and general principles of life management was enumerated, and the fatigue life law and development history of deve lopment bearings was introduced. The basic failure damage model of rolling bearing for locomotive and rolling stock was studied and sorted out, display the general life trend of rolling bearing and the relationship between various lives. The remaining life law of railway bearing was studied, and the total available working capacity of batch bearing and the operational risk of remaining life were calculated. The difference between repairing bearing and newly built bearing was pointed out. The economic value of remaining life was calculated, and the feasibility, reliability and operational risk of rolling bearing repair after stage operation were tested. It was suggested that the life management of rolling bearing for locomotive and rolling stock is scientificed and the cost and risk is optimized.

采用金相显微镜(OM)、透射电镜(TEM)、电子背散射成像技术(EBSD)和X射线,对比分析喷射成形Al-9Mg-1.8Li合金交叉轧制态板材与挤压态板材的微结构及织构特征,并测试板材的拉伸性能和深冲性能.结果表明:大变形量交叉轧制促进动态再结晶的发生,细化晶粒组织,改善再结晶晶粒的择优取向;与CBA和CCB轧制方式相比较,CBB轧制方式显著降低挤压态合金中典型的Brass织构{110}<112>的取向密度,在β取向线上CBB轧制态板材中的Copper织构{112}<111>取向密度最低,且板材中没有典型的织构特征;同时,CBB轧制态合金板材的具有更好的深冲性能,在0°、45°和90°方向的力学性能基本一致,其室温拉伸强度、屈服强度和伸长率分别在611 MPa、507 MPa和20.6％以上.

The flow stress behavior of spray-formed Al-9Mg-1.1Li-0.5Mn alloy was studied using thermal simulation tests on a Gleeble-3500 machine over deformation temperature range of 300-450 °C and strain rate of 0.01-10 s−1. The microstructural evolution of the alloy during the hot compression process was characterized by transmission electron microscopy (TEM) and electron back scatter diffractometry (EBSD). The results show that the flow stress behavior and microstructural evolution are sensitive to deformation parameters. The peak stress level, steady flow stress, dislocation density and amount of substructures of the alloy increase with decreasing deformation temperature and increasing strain rate. Conversely, the high angle grain boundary area increases, the grain boundary is in serrated shape and the dynamic recrystallization in the alloy occurs. The microstructure of the alloy is fibrous-like and the main softening mechanism is dynamic recovery during steady deformation state. The flow stress behavior can be represented by the Zener-Hollomon parameter Z in the hyperbolic sine equation with the hot deformation activation energy of 184.2538 kJ/mol. The constitutive equation and the hot processing map were established. The hot processing map exhibits that the optimum processing conditions for Al-9Mg-1.1Li-0.5Mn alloy are in deformation temperature range from 380 to 450 °C and strain rate range from 0.01 to 0.1 s−1.

为了获得工业包装用高强高韧铝合金材料,采用喷射成形快速凝固技术和大压下量轧制技术制备了Al-9Mg合金板材.采用透射电镜、扫描电镜(采用EBSD技术)和X射线衍射仪测定了挤压态和轧制态Al-9Mg合金板材的微结构及织构特征,并测试了板材的各向异性行为.试验结果表明:大压下量交叉轧制CBA促进了动态再结晶的发生,细化了晶粒组织,显著提高了大角度晶界的比例;与挤压态和AAA轧制方式相比较,CBA轧制方式显著降低了挤压态合金中典型的Brass织构{110}<112>的取向密度,在β取向线上CBA轧制态板材中的Brass织构取向密度最低,且板材中没有典型的织构特征;同时,CBA轧制态合金板材具有更好的深冲性能,在3个方向0°,45°和90°的力学性能基本一致,其室温拉伸强度和伸长率分别在592 MPa和19.6％以上.

详细介绍了南非运煤专线26 t轴重电力机车转向架的主要技术参数和主要结构特点,对驱动单元、轮对轴箱组装、构架、悬挂装置及牵引装置等关键零部件的结构进行说明和分析计算.并重点介绍了南非窄轨重载货运电力机车动力学仿真计算及线路试验情况.结果表明,南非运煤专线26 t轴重电力机车转向架技术先进,性能可靠,完全满足南非业主的要求,并为研制其他窄轨机车转向架提供了宝贵的参考.

The high intensity and high strength Al2O3 ceramic green body was prepared by direct coagulation casting (DCC) in Mg2+ system.Effects of different addition of MgO and dispersants on physical and mechanical properties of Al2O3 ceramics were analyzed.The results reveal that the Al2O3 with 55 ％ solid content has release strength of 207 kPa.The viscosity of Al2O3 slurry reaches the lowest of 65 mPa · s,and low viscosity slurry is conducive to vacuum agitation degassing and it is suitable for injection molding operation with dispersant concentration of 1.2 ％.In addition,the solidification time is 170 min when the MgO addition is 0.3％.Meanwhile the density after sintering reaches up to 3.93 g/cm3,which is 99％ of theoretical density.