60Si2MnA钢片弹簧断裂失效分析

某60Si2MnA钢片弹簧在使用10h后出现批量断裂,对断裂片弹簧进行了化学成分分析、硬度测试、金相检验以及断口微观形貌观察,以查明其断裂原因。结果表明:片弹簧断裂是由于在酸洗、电镀过程中析氢反应的发生,使其产生氢脆现象;同时由于热处理工艺过程控制不当,造成组织异常,硬度高于技术要求,加快了其氢脆倾向,最终导致片弹簧在外应力作用下发生氢脆断裂。     

碟形弹簧力学性能研究

针对组合碟形弹簧力学性能数值模拟方法存在较大差别、尚无统一加载及边界约束条件、缺乏对阻尼特性定量描述问题,选B系列碟形弹簧分别对单片、2片叠合、3片叠合、3片叠合2组对合、3片叠合6组对合等组合碟形弹簧进行静、动力加载性能试验,考察加载预压量、动荷载幅值、加载频率对等效刚度、阻尼比影响;利用ANSYS软件模拟试验工况,基于静力加载试验实测数据考虑碟形弹簧与上下压板间摩擦作用,计算碟形弹簧锥面间摩擦系数等效值,并用于组合碟形弹簧件承受动荷载的数值模拟,与试验结果吻合较好。     

地铁车辆一系簧断裂问题的试验研究

国内某项目地铁车辆运行中出现一系钢簧断裂现象,依据断裂位置及现象进行金相分析及在线试验。结果表明,车辆在部分运营区间弹簧应力很大,在大的交变载荷下产生疲劳源并造成疲劳断裂。应力频率与转向架振动频率基本一致,且与仿真计算的弹簧安装状态下固有频率一致,判断产生了共振现象。     

配后置式发动机整车的少片变截面钢板弹簧卷耳早期失效原因及可靠性提高途径

在实施少片变截面汽车钢板弹簧产品创新的过程中,我们发现少片变截面钢板弹簧卷耳早期疲劳失效现象(其故障里程≤15000km或有效运行时间不超过2个月)带有共同性的原因.因此,研究其失效的原因并提出提高其疲劳寿命的措施,无疑会促进少片变截面钢板弹簧技术进步的发展,促进生产企业、客车业主的经济效益,同时也具有良好的社会效益.     

全封闭活塞式制冷压缩机气阀弹簧力的计算

本文从活塞式压缩机气阀的运动规律出发,提出了选择恰当的气阀弹簧的弹簧力来减小阀片对阀座的冲击,并依据H·Davis气阀可靠性准则及全封闭制冷压缩机的试验数据,找出计算全封闭活塞式制冷压缩机气阀弹簧力的经验公式及计算方法。     

汽车发动机气门弹簧断裂分析

针对汽车发动机气门弹簧在台架试验中的断裂问题,对断裂弹簧的外观、化学成分、显微组织、断口形貌以及断口微区成分等进行了检测与分析,并对气门弹簧断裂的原因进行了分析。结果表明:由于钢丝储存不当造成表面腐蚀缺陷,导致气门弹簧在试验时出现了早期疲劳断裂。     

矩形截面扭转弹簧扭矩的预置扭矩检测法

矩形截面扭转弹簧的扭矩检测缺乏相应的标准进行规范,导致其检测结果的重复性较差。通过理论分析和试验验证,发现采用预置扭矩的方法对矩形截面扭转弹簧进行扭矩检测后,检测结果的重复性明显提高。在对矩形截面扭转弹簧的扭矩检测过程中,在弹性阶段利用预置扭矩的办法可以改善起测点不稳定的现象,减少或避免扭转弹簧的非稳状态对试验结果的影响。     

少片钢板弹簧片间动摩擦系数计算方法研究

为研究钢板弹簧的片间动摩擦特性,提出一种少片钢板弹簧片间动摩擦系数计算方法。首先根据少片钢板弹簧的变形运动学特性,推导出少片钢板弹簧动摩擦系数与静摩擦系数的关系;然后分别基于力学法和能量法建立少片钢板弹簧静摩擦系数计算模型,根据摩擦功相等原理,得出板簧静摩擦系数计算方法;最后根据钢板弹簧动、静摩擦系数的关系,推导出少片钢板弹簧片间动摩擦系数计算方法。计算结果表明:摩擦系数的计算值和实际工况值基本吻合。以某企业实际板簧为例,对上述计算模型进行了实验验证。     

55CrSi钢气门弹簧断裂原因分析

采用化学成分分析、金相检验和硬度测试等方法对Ф3．6mm55CrSi钢气门弹簧在台架试验中的断裂原因进行分析。结果表明：由于钢丝表面存在的脆性非金属夹杂物,导致气门弹簧在试验时出现早期疲劳断裂。     

铁路重力式桥墩抗震计算简化模型研究

针对低配筋铁路重力式桥墩破坏时仅在墩底形成一条主裂缝,墩底混凝土压碎不明显,未形成塑性铰区,且动力作用下有明显摇摆现象的特征,提出了一种适用于该类桥墩的抗震计算简化模型,即在自由摇摆桥墩双弹簧模型的基础上再加上考虑纵向钢筋仅受拉的两个弹簧的四弹簧模型。依据模型桥墩试验结果确定了仅受拉弹簧刚度的参数取值;通过静力作用下和动力作用下的四弹簧模型计算值与试验值对比,验证了四弹簧抗震分析模型可用于铁路重力式桥墩的抗震简化计算。     

Spring stiffnesses of composite circular springs with extended flat contact surfaces under unidirectional line-loading and surface-loading configurations

Theoretical expressions based on the principle of minimum potential energy are presented which describe the stiffnesses of mid-surface symmetric, woven composite circular springs with extended flat contact surfaces subject to unidirectional line and surface-loading configurations. Three-dimensional finite element analysis has been employed to study the transverse shearing effects. Eighteen woven fibre/epoxy composite circular springs with extended flat contact surfaces in different radii and thicknesses were fabricated and tested. Comparison studies of the results obtained from both the analytical and numerical models are made with experimental data, and the results are found to be satisfactory. The semi-included angle of the flat contact surface is vital parameter to spring stiffnesses of the composite spring.     

Failure analysis of the suspension spring of a light duty truck

In this paper the failure of the rear suspension spring is analyzed in detail. The rear axle suspension system of the truck and fractured flat spring is investigated. Fracture surface, mechanical and chemical properties and microstructure of the spring material is analyzed. Forces acting on the spring is determined and strength calculations are carried out. Later, failure behaviour and cause of fracture is revealed after carefully analysis of microstructure and results of calculations. At the end precautions to be taken to prevent a similar failure is recommended.     

转动惯量在线测量用涡卷弹簧的设计

针对正弦扭矩标准装置气浮轴系的转动惯量在线测量需求,根据机械标准设计一非接触平面涡卷弹簧,用于测量正弦扭矩标准装置气浮轴系转动惯量.因该涡簧圈数较少(小于设计标准中建议的三圈以上),因此通过有限元分析软件ANSYS分析该涡簧的特性曲线,仿真结果表明:该涡簧能够稳定提供足够的反作用力矩驱动气浮轴系作扭摆运动.实际测试结果...     

Failure analysis on the collapse of leaf spring steels during cold-punching

In this paper, the collapsing fracture of 60Si2Mn spring flat steels during cold-punching is analyzed by use of an optical microscope, a scanning electronic microscope, an optical stereomicroscopy, an energy dispersive spectrometer, an inductively coupled plasma-mass spectrometry, the hardness testers and a Charpy impact tester. The results show that the collapsing fracture of 60Si2Mn spring flat steels during cold-punching is due to the non- homogenization of microstructures and the nonmetallic inclusions. When the spring flats are cold-punched, the different deformation properties of the inclusions, the ferrites and the cementites initiated micro-cracks. The micro-cracks propagate along the interfaces of ferrites and cementites. The collapsing fracture is characteristic with transgranularity, cleavage and pearlites. The large space lamella pearlites with low strength are the main reason of the cleavage transcrystalline fracture. The prevention measurements are suggested.     

SAE6150弹簧扁钢热卷耳开裂原因分析

采用外观观察、电镜分析、金相检验等方法，对弹簧扁钢在热卷耳过程中发生的开裂原因进行了分析。结果表明热加工过程中温度控制不当，引起扁钢局部过烧进而导致卷耳变形时发生严重开裂现象。     

A Finite-Element Analysis on the Rheorolling Process of Semi-Solid Spring Steel

With a geometrical model of porous material, a 3D finite-element analysis on the rolling process of spring steel60Si2Mn in the semi-solid state is carried out using software MARC. In terms of flat and groove rolling conditions,stress field and strain fiel     

NHK扁钢质量改进

通过对NHK弹簧扁钢的质量合格率的统计分析，发现主要有刮伤、翘皮、弯曲三种质量缺陷，按工艺流程对生产各工序容易产生的质量缺陷进行了分析，并结合生产实际提出了相应的解决方法。     

Einfluß des Richtens auf das mechanische Verhalten von Federlegierungen

Influence of Levelling Processes on the Mechanical Behaviour of Spring Alloys Levelling processes – that means straightening of wire or level rolling of strip – have an impairing effect on the R_p0,2 and R_p0,1 proof strength of cold worked spring alloys and on the hysteresis behaviour of flat springs respectively. SEM and TEM investigations indicate that recovery is initiated by levelling processes and is intensified by a subsequent age hardening treatment. This may lead to a modification of age hardening behaviour and effectivity for those alloys which show different age hardening mechanisms in the cold worked and recovered state respectively. The detrimental influence of level rolling on the hysteresis behaviour is found to be due to an increased subgrain size after age hardening treatment. The results show that improvement of geometry by levelling processes is only possible at the cost of decreased spring properties.     

挠性枢轴支承扭转刚度的计算探讨

挠性枢轴支承是一些用于航空，航天领域内的高精密装置的关键部件之一，它的扭转刚度及对应的变形状态是支承在工作时必须控制的重要性能指标，这些指标如不符合要求，整个装置将会失效。该数产品目前仍依赖进口。本文应用计算功能与ＡＤＩＮＡ相同的ＭＦＥＰ软件中的ＭＦＧＳ方法对有着支承样品的上述性能进行了非线性有限元计算和相应的线性有限元计算，计算结果表明，支承弹簧片插入弧形体中那部分的实际焊接深度对上述的性能有很     

Randschichteigenspannungen durch mechanisches Schleifen bei hochfesten Federstählen

Oil tempered steel, like the high strength spring steel 54SiCr6 (1.7102), is mainly used for helical springs. To enlarge the contact area between spring and adjacent parts, the spring tail is often flat‐grinded. Due to wire‐drawing process residual stress is already existing before spring manufacturing. The spring manufacturing process contains several sequenced steps like winding, even grinding and shot peening. All of these steps cause additional or influence the existing residual stress in wire. The knowledge of these mechanisms and the level of residual stress is mandatory for design of application and its operation. Grinding processes in general has major influence to the residual stress level. In fact the choice of grinding parameter is essential for the stress height. In general: thermal effects while grinding cause basically tensile stress, mechanical effects cause basically pressure stress. Presented investigation shows the qualitative influence of several grinding parameters like infeed, conventional or synchronized grinding operation mode and the optional usage of cooling lubricant. The superposition of grinding‐based residual stress with different residual stress depends not only on the stress‐height but also on the characteristic. Therefore universally statements are not available.