锻造变形工艺对挤压凹模寿命的影响

针对圆锥内圈原有锻造工艺挤压凹模寿命低的问题，调整工艺，将大挡边由挤压时成形改为冲孔时压成，去掉了挤压凹模易损坏的R角，凹模寿命提高了10倍。     

浮动凹模对带六边形孔的圆柱直齿轮冷精锻的影响

以带六边形通孔的直齿轮为例,通过有限元仿真软件DEFORM-3D对直齿轮冷精锻的几种浮动凹模工艺进行数值模拟,分析了浮动凹模工艺(凹模和上凸模以相同的速度下行)、浮动凹模配合轴分流工艺和浮动凹模预锻+浮动凹模轴分流终锻两步成形三种工艺的充填情况和载荷大小。研究结果表明,采用浮动凹模工艺锻件的充填情况较好,但是成形载荷较大;采用浮动凹模配合轴分流工艺,不仅齿形充填效果较好,而且能有效地降低成形载荷;采用浮动凹模预锻+浮动凹模轴分流终锻工艺的齿形充填效果较好,能显著地降低成形载荷。     

冲压模具零件的制造工艺

以级进冲裁凹模结构形状和技术要求为研究对象，介绍了级进凹模加工过程中遇到的问题和解决方法。着重阐述了级进冲裁凹模的加工工艺性及加工工艺方案，并详细说明了模具零件的加工工艺过程。     

采用波形端面凸模的齿轮精锻工艺优化

采用数值模拟和物理试验相结合的方法，对直齿轮精锻工艺进行了分析。试验结果既说明此工艺方案可行，也验证了数值模拟的可靠性，为该工艺方案的优化设计奠定了基础。结合正交试验设计方法和数值模拟技术，以分流角、凸模成形角、反向凸模成形角和分流距4个模具设计的关键参数作为设计变量，以成形时所需工作载荷最小为优化目标，对工艺方案进行了优化。最后引入浮动凹模设计的思想，模拟了采用浮动凹模结构的优化方案的成形过程，采用浮动凹模的优化方案与传统方案和优化方案的模拟结果的对比分析发现，采用浮动凹模可以进一步降低工作载荷。     

螺母冲孔废料的利用

最近我厂在冲制螺母时,将其废料连皮经过滚光、软化、退火、压片,再经过冲挤修整以及磷化、皂化等工序,制成了气门帽的冷挤压前毛坯,节省了大量的原材料,现将其工艺介绍如下。图1为气门帽冷挤压前冲挤修整毛坯的工艺图。图1a为螺母冲孔废料,1b为废料压成的毛坯片,1c为经过上层凹模冲挤后的毛坯,1d为经过下层凹模修整后     

65Nb钢模具热加工工艺试验

对链板冲压模的强度、韧性和耐磨性提出越来越高的要求,但提高强度和硬度往往带来韧性不足。本文讨论链板冲裁凸凹模选材、锻造加工、球化退火、热处理工艺,重点讨论65C14W3Mo2VNb（65Nb钢）热处理工艺参数对钢的性能和组织的影响。通过改善冷冲模钢的强韧性,可大幅度地提高链板冲裁模（凸模、凹模和凸凹模）的使用寿命。     

提高热挤压凹模寿命的加工工艺

通过对热挤压凹模失效进行分析，找出了失效原因，并对相应的加工工艺进行了改进。生产实践结果表明，经过这种加工工艺的改进，该凹模的平均使用寿命提高了2-3倍。     

棒材开式冷挤压过程中挤压凹模的数值模拟研究

在棒材开式冷挤压过程中，凹模内壁受力大小是影响凹模设计的一个很重要衡爨指标。文中采用有限元软件Deform-3D，对棒材开式冷挤压过程进行数值模拟，得到凹模内壁所受应力的分布规律及各个工艺参数对凹模内壁所受应力的影响规律，并获得减小凹模内壁应力的参数优选范围，从而达到优化参数的目的。     

T10A钢碳化物超细化处理的实践

针对T10A钢制作的简单冷冲模具，经常规热处理后，在生产过程中凹模常会出现韧性差，发生早期断裂失效现象。本文对常规热处理工艺进行了分析，提出了凹模碳化物超细化处理工艺，达到了预防凹模出现早期断裂和提高寿命的目的．     

圆锥形凹模径向分块压边拉深工艺实验研究

采用圆锥形凹模拉深工艺可以提高成形极限,但需要用压边圈将板坯先压成与凹模面吻合的形状,当变形程度较大时,板坯很容易起皱。为了克服这一缺点,提出了将圆锥形凹模与径向分块压边方法结合的工艺,该工艺可有效改善压边圈与板坯的约束状态,从而达到抑制起皱的目的。对圆筒形件的拉深成形,采用了刚柔复合的径向分块压边圈结构,设计了圆锥形凹模径向分块多压边圈拉深模,取不同凹模半锥角的圆锥形凹模进行了圆筒形件的拉深成形实验。实验表明,新的压边方法能有效克服初始成形过程的起皱,可与锥度较小的凹模一起使用。采用凹模半锥角为45°的凹模,得到AA5754、AA6061和08Al三种板材的极限拉深系数分别为0.410、0.431、0.373,显著提高了成形极限。对圆锥形凹模的拉深成形,给出了理论计算成形极限的方法,理论与实验结果非常接近。     

提高花键轴冷挤压模具寿命研究

防止模具早期失效,提高模具寿命是研究冷挤压工艺在花键轴加工中应用的重要环节。分析花键轴冷挤压模具的几种常见失效形式及其特点,从模具材料选择、模具结构设计以及坯料的热处理等方面提出了提高模具寿命的措施。     

热加工工艺对锻模寿命的影响

分析研究了从冶炼、锻造及热处理等锻模热加工的各工序对锻模使用寿命的影响,并制定了预防锻模早期失效和提高锻模使用寿命的措施。重点阐述了模坯锻造过程中应注意的工艺技巧及方法,提出了针对热锻模具采用不同的热处理工艺和表面强化处理方法。     

金属型铝合金浇铸模寿命影响因素分析

金属型寿命的长短直接关系到生产效率及成本,是模具制造业关心的核心问题。本文介绍了金属型铝合金浇铸模主要失效形式,并对金属型材料、热处理、结构设计、铸造工艺、冷却、使用强度等影响模具寿命的因素进行了分析,对延长金属型寿命提出了可行性措施。     

滚动轴承疲劳寿命的影响因素

对影响滚动轴承疲劳寿命的各种因素进行了综述，包括各种疲劳诱导应力(最大切应力、最大动态切应力、Von Mises应力和八面切应力)，切向力、残余应力和环向应力疲劳极限应力、表面粗糙度、弹流润滑、表面处理、润滑油中污染颗粒、温度、速度、不失效寿命和钢材纯净度(氧含量)的影响，为轴承寿命的准确预测提供参考。     

高压阀门泄漏原因分析及带压堵漏处理

阀门是石化工业和流体控制必不可少的装置,而阀门的泄漏又是阀门使用中经常遇到的问题,尤其是在高压管线的使用中,阀门的泄漏会造成非常严重的生产故障,甚至造成整条生产流程的停顿,结合氧化铝生产流程中使用的高压阀门实际情况,重点分析了高压阀门泄漏的原因并给出了常用的带压处理措施.     

Methodology to Estimate Remaining Service Life of Steel Structure by Possibilistic Reliability Theory

Steel structure system of crane deteriorates over time due to environmental effects,material fatigue,and overloading.System structural reliability and remaining service life assessment methods are developed during the few decades.But until now estimating remaining service life methods of crane steel system by reliability theory begin to develop.Safety assessment of existing steel structure system requires the development of a methodology that allows for an accurate evaluation of reliability and prediction of the remaining life.Steel structures are the supporting elements in the special equipment such as hoisting machinery.Structure reliability and remaining service life safe assessment are important for steel structures.For finding the reason which caused the failure modes(such as fatigue strength failure,stiffness failure and stability failure),incremental loading method based on possibilistic reliability is applied into dynamic structure failure path research.Through reliability analyzing and calculating for crane,it is demonstrated that fatigue damage is the most common failure mode.Fuzzy fatigue damage accumulation theory is used for basis theory and Paris-Eadogan equations are used for mathematical modeling.All fatigue parameter values of the welding box girder of bridge cranes are determined and fatigue remaining life formulas are deduced.After field test and collecting working parameters of numerous cranes,typical fatigue load spectrum was compiled for the dangerous point of box girders used in the area.Fatigue remaining life is assessed for different types and lifting capacities.Safety for steel structure system of bridge crane is assessed by two quantitative indexs:reliability and remaining life.Therefore,the evaluation means is more comprehensive and reasonable.The example shows that the two quantitative indexs are mutually correlated.Through analyzing the 120 t-22.5 m bridge crane of a certain enterprise,a new methodology to estimate remaining service life of steel structure by possibilistic reliability theory is introduced for safety evaluation of structure system.     

Effect of sursulf treatment on the performance of 0.14% C steel gears

Sursulf-treated low carbon steel gears were tested in a back-to-back gear test rig. The failure of the gears is by pitting and the contact stress-pitting life curve has been established. Wear particle analysis of the lubricating oil was carried out to analyse the nature of the failure. The study reveals that Sursulf treatment on low carbon steel gears considerably improves their performance. The cumulative wear particle concentration at the pitting limit has been suggested as a basis for predicting the onset of failure of the gears.     

Time-dependent vibration frequency reliability analysis of blade vibration of compressor wheel of turbocharger for vehicle application

Blade vibration failure is one of the main failure modes of compressor wheel of turbocharger for vehicle application. The existing models for evaluating the reliability of blade vibration of compressor wheel are static, and can not reflect the relationship between the reliability of compressor wheel with blade vibration failure mode and the life parameter. For the blade vibration failure mode of compressor wheel of turbocharger, the reliability evaluation method is studied. Taking a compressor wheel of turbocharger for vehicle application as an example, the blade vibration characteristics and how they change with the operating parameters of turbocharger are analyzed. The failure criterion for blade vibration mode of compressor wheel is built with the Campbell diagram, and taking the effect of the dispersity of blade natural vibration frequency and randomness of turbocharger operating speed into account, time-dependent reliability models of compressor wheel with blade vibration failure mode are derived, which embody the parameters of blade natural vibration frequency, turbocharger operating speed, the blade number of compressor wheel, life index and minimum number of resonance, etc. Finally, the rule governing the reliability and failure rate of compressor wheel and the method for determining the reliable life of compressor with blade vibration is presented. A method is proposed to evaluate the reliability of compressor wheel with blade vibration failure mode time-dependently.     

汽车底盘电控系统常见故障诊断与维修

随着人们生活水平的不断提高,汽车进入到千家万户中,为人们日常出行生活提供了极大的便利;而底盘作为汽车整体结构的重要环节,在很大程度上影响着汽车运行过程的稳定性,由于汽车行驶过程中极易出现磕碰,且部分部件结构使用寿命不断降低,增加了底盘故障问题出现的概率,对汽车行驶稳定性、驾驶人员舒适性及安全性等方面有着极大地影响;为了解决这些问题,汽车制造企业需要加强现代化技术的应用,借助电控系统对汽车底盘故障问题进行仔细诊断,根据外观、气味、温度及声响等条件明确故障类型,以此来制定科学有效的维修处理方案,保障底盘及汽车整体的质量与使用寿命,为我国现代汽车维修行业整体的健康发展奠定坚实基础。下面主要对汽车底盘电控系统常见的故障诊断与维修进行分析探究。     

浅析煤矿机械中齿轮失效形式及对策

煤矿机械设备中齿轮的失效是产生设备故障的主要原因,本文研究了煤矿机械设备中齿轮失效的形式,分析了产生齿轮失效的几个方面的原因,并针对每个方面提出了改进措施,从而能更好的避免因齿轮失效而造成的煤矿机械故障,延长机械设备的使用寿命。