基于局部应力应变法的弧齿锥齿轮锻造模具寿命预测

模具寿命是影响弧齿锥齿轮锻造成本的主要因素之一。采用弹塑性有限元模型,对弧齿锥齿轮热锻成形的模具应力分布进行了模拟仿真,基于局部应力应变法,从模具的预热温度、齿模齿顶的过渡圆弧半径以及锻造成形速度等工艺因素计算模具的应力应变分布,分析各工艺因素对模具寿命的影响规律。模拟结果表明,热锻成形的弧齿锥齿轮的模具失效形式,主要为齿模的齿顶和齿根处应力集中引起的断裂。对于齿模的齿顶位置来说,三种工艺参数的变化与齿模疲劳寿命成正比。对于齿模的齿根位置来说,工艺参数的变化与模具寿命成反比。提出的模具寿命预测方法为批量化生产中优化模具结构和预测模具寿命提供了技术参考。     

从动螺旋锥齿轮齿坯热模锻工艺参数优化设计

基于Archard磨损理论,运用正交试验优化设计方法,采用刚塑性有限元法对从动螺旋锥齿轮齿坯热模锻过程进行了模拟分析,研究了模具预热温度、锻压速度、模具硬度、摩擦因数等四个参数对成形载荷和模具磨损量的影响;以成形载荷和模具磨损量为优化指标,采用综合平衡分析方法,得到了最佳工艺参数并对其进行了验证。研究结果可为从动螺旋锥齿轮齿坯热锻成形工艺方案的改进及模具寿命的预测提供参考。     

精密体积成形模具设计制造及其寿命

主要论述精密体积成形(精锻)模具寿命与模具设计制造的关系。采用先进的设计手段,合理地设计精密体积成形件(精锻件)、锻压工艺、模具结构,选择模具材料,以及正确地制定模具钢的锻造和热处理工艺,同时正确制定机械加工工艺,大幅度提高模具寿命。     

弧齿锥齿轮精锻成形模具磨损特性分析

采用刚塑性有限元法对弧齿锥齿轮精锻成形过程中模具表面磨损进行模拟分析,研究了摩擦因数、坯料温度、模具硬度、锻压速度等对模具磨损的影响.分析结果表明,随着摩擦因数的增大,磨损量增大;随着锻压速度、坯料初始温度及硬度的增大,磨损量减小,并且硬度是影响模具表面磨损量最重要的因素.模拟结果可为弧齿锥齿轮精锻成形工艺方案制定及模...     

爪极锻造工艺参数多目标优化

随着车载电器技术的不断进步和发展,对发电机爪极发电等性能的要求也越来越高。基于Archard磨损模型,针对影响爪极精锻模具寿命的工艺参数,设计正交试验。通过Deform数值模拟,研究了坯料初始温度、模具初始温度、模具硬度、成形速度以及工件与模具之间摩擦系数对成形载荷和模具磨损的影响。综合考虑多目标因素,优化了爪极成形的工艺参数,分析得到了影响爪极成形载荷和模具磨损量的最优工艺参数.研究表明:按照最优工艺参数精锻模具寿命可以提高57.025%。     

精锻弧齿锥齿轮模具齿形的切削加工探究

阐述了采用刀倾法成形切削加工精锻弧齿锥齿轮模具齿形的方法和由齿轮参数反算模具齿形参数的原理。分析了锻造大轮的造型误差 ,提出了保证锻造大轮和小轮正常啮合的方法 ,并给出有关的计算公式。     

弧齿锥齿轮塑性成形工艺研究

针对弧齿锥齿轮开式模具存在的问题,提出了弧齿锥齿轮闭式挤压新工艺及其模具结构,该模具采用浮动凹模和浮动凸模结构,工件在2个凹模和2个凸模形成的封闭模腔中成形,生产的工件无飞边。工艺试验表明,新工艺可显著降低挤压变形力、材料消耗和生产成本,提高模具寿命和生产效率。     

精锻弧齿锥齿轮模具齿形的切削加工探究

阐述了采用刀倾法成形切削加工精锻弧齿锥齿轮模具齿形的方法和由齿轮参数反算模具齿形参数的原理，分析了锻造大轮的造型误差，提出了保证锻造大轮和小轮正常啮合的方法，并给出了有关的计算公式。     

超大规格GH4169高温合金螺栓成形工艺及模具结构优化

针对大规格GH4169高温合金螺栓成形难度大、模具易开裂寿命低等问题,研究其成形工艺及模具结构.结合金属塑性成形理论,提出其成形工艺方案.采用Deform-3D有限元分析软件对提出的工艺方案进行数值模拟,分析了成形过程中的载荷-行程曲线、金属流动规律等,根据成形工艺,设计并优化相应模具结构,最后进行了工艺试验.通过数值...     

离合器内齿轮包挤压成形工艺及实验研究

研究了在离合器上使用的圆柱直齿内齿轮的加工工艺,与当前使用的冷挤压法成形工艺的比较表明,该工艺克服了冷挤压成型齿时载荷大,模具凸模磨损严重,使用寿命短的缺陷,解决了直接冷挤压成形内齿轮中的产品质量一致性不够好的问题,得到了齿形饱满,端面平整的内齿轮,而且成形内齿与预挤分开,使带齿模具凸模寿命可得到延长,具有生产实用化的前景。     

Estimation of die service life for a die cooling method in a hot forging process

Dies may have to be replaced for a number of reasons, such as changes in dimensions due to wear or plastic deformation, deterioration of the surface finish, breakdown of lubrication, and cracking or breakage. In this paper, die cooling methods are suggested to improve die service life with regards to wear and plastic deformation in a hot forging process. The yield strength of die decreases at higher temperatures and is dependent on hardness. Also, to evaluate die life due to wear, a modified Archard’s wear model has been proposed by considering the thermal softening of die expressed in terms of the main tempering curve. This paper describes the effects of die cooling methods such as cooling hole and direct spray cooling on the life of finisher die during the hot forging of an automobile part. It is shown that the cooling hole method during hot forging is necessary for an effective die service life to be obtained.     

基于钴基合金覆层的多层金属热锻模原型制备与性能

基于功能梯度材料(FGM)的思想制备多层金属热锻模是提高模具寿命的有效方法。采用焊条电弧堆焊制备了多层金属热锻模的原型试样,试样经焊后热处理后,进行了金相组织分析、显微硬度测试、磨损实验和冲击韧性测试等实验。实验结果表明:钴基合金堆焊层与W6Mo5Cr4V2堆焊层界面冶金结合情况良好;截面显微硬度呈梯度分布,表面钴基合金硬度达到492HV;制备的多层金属试样耐磨性是H13钢耐磨性的2.5倍,冲击韧性处于合理范围。     

基于PDCA理论的模具制造车间质量管理

为了延长凸模的使用寿命,运用全面质量管理的PDCA循环法,针对凸模质量失效问题进行了分析,并以T型冲头为例,对冲头加工的热处理工艺和机加工工艺进行改进,提高了冲头产品的硬度、韧性和耐磨性,最后以应用实例证明了应用PDCA法对冲模进行质量管理能够为企业取得良好的经济效益。     

基于预成形设计和分流技术的锻造螺旋锥齿轮工艺改进和试验

齿形充满不充分和成形载荷过大是螺旋锥齿轮锻造近净成形的主要问题。利用弹塑性有限元法模拟螺旋锥齿轮从动轮一火两锻的半闭式锻造过程,提出通过优化预成形件面锥形状以改善轮齿端角隅部位填充不满的现象,运用正交试验优化设计方法,确定预锻件高度、圆弧弦高、圆弧弦角以及圆弧高点离轮齿小端的距离4个工艺因素对轮齿充满程度和成形载荷的影响规律,选出最佳工艺因素组合。在此基础上提出在轮齿小端设计分流腔的模具结构,以进一步改善齿轮小端角隅充满不理想的现象,对比分析两种工艺方案的成形载荷的峰值,分流锻造成形载荷减小了22.45%。在25MN电动螺旋压力机上进行锻造试验。通过数值模拟和试验结果的对比分析,验证了新工艺方案的有效性。      

基于修正Archard磨损理论的挤压模具磨损分析

基于修正的Archard磨损理论,应用有限元数值模拟软件计算模具挤压成形阶段每个节点的瞬时温度、压力和速度场,以此计算锥形和弧形两种挤压模具型腔的磨损。计算结果表明:挤压模具磨损集中在入口,弧形凹模磨损较锥形凹模磨损大,但弧形凹模磨损均匀,模具寿命较高。磨损计算结果与实际情况较吻合,为预测模具寿命和优化模具型腔奠定了基础。     

A method of determination of the service life of a die tool with application of magnetic methods of nondestructive control and diagnostics

Based on the representative sampling of experimental data and processing of the obtained results, a method of determination of the service life of the instrument for cold sheet s is developed. The method is based on correlation between the magnetic, mechanical and physical-chemical (chemical composition, thermal processing mode, plastic deformation, micro- and macrostress, positioning of dislocations, etc.) properties of the die tool materials.     

Method for improvement of die-casting die: combination use of CAE and biomimetic laser process

Die service life improvement is an important problem in high-pressure die-casting industry. Die service life, which is defined as the maximum product number produced before it fails, and die performance directly determine the production cost and quality of die-casting product. To reduce the repair and maintenance costs, an approach to prevent die from thermal damage and prolong the die lifetime is required. Biomimetic laser-remelting process (BLRP) provides a promising method to improve the service life of die-casting mold. However, the laser processing regions can only be determined by experiences. In order to determine the exact laser processing regions for a set of new die before BLRP, a combination system of CAE and BLRP is proposed in this paper. Through analyzing the mold filling process and the temperature distribution, potential thermal cracks are worked out by numerical simulation system, which are the laser processing regions. The method proposed in this paper advances the efficiency of the BLRP. And practical production validates the veracity and the reliability of the method.     

热挤压模磨损规律及磨损对模具寿命的影响

采用Archard磨损模型模拟分析了模具硬度、初始温度、润滑条件在一次成形后对模具磨损的影响规律。结果表明：模具初始硬度越高,模具抗磨损能力越强;当摩擦因子m〉0.35时,模具的磨损量迅速增大;温度对磨损的影响较为复杂,一方面温度使模具表层发生软化,加速磨损,另一方面温度又使模具表面形成氧化膜,阻止金属表面的大面积接触,磨损量反而减小。最后将温度引入Archard磨损模型中,提出了用磨损量来预测模具使用寿命的新方法。     

Microstructure and properties of surfacing layers of dies manufactured by bimetal-gradient-layer surfacing technology before and after service

The purpose of this article is to investigate the microstructure and mechanical properties of surfacing layers (wear layer and transition layer) of a hot forging die manufactured by the bimetal-gradient-layer surfacing method, which is based on ZG29MnMoNi cast steel before and after forged 5761 parts on a 63MN hot die forging press. The finite element model of a die was established. Subsequently, a simulation was conducted to analyze the temperature field of the die and its cycle features under working conditions. Microstructure and mechanical property were measured. Results indicated that the microstructure of the wear layer mainly consists of temper sorbite, ferrite and carbides. The transition layer before and after service is mainly composed of both temper sobrite, lower bainite, and a small amount of temper martensite. The mechanical properties of wear and transition layers declined significantly after service. The tensile strength, yield strength, reduction of area, and elongation of wear layer declined by 41.6, 32.5, 28.3, and 24.5 %, respectively. With those indexes the transition layer decreased by 36.6, 34, 24.4, and 19.8 %, respectively. Microhardness and impact energy of wear and transition layers have showed a decrease of 17, 6 % and 51.2, 32.6 %, respectively. The impact fracture mode of both wear and transition layers is typically intergranular fracture after service. As a conclusion, it was determined that the service process sufficiently influenced the mechanical properties of the surfacing layers.     

脉冲电磁处理参数对YT15硬质合金服役寿命的影响

采用COMSOL Multiphysics有限元分析软件对脉冲电磁处理设备进行仿真建模,利用正交试验的方法研究了磁通密度、磁脉冲个数、脉冲电压、电脉冲组数对YT15硬质合金刀具服役寿命的影响规律。通过极差分析得到了各因素的影响主次关系以及最佳脉冲电磁处理参数,并分析了切削过程的主切削力及磨损量变化,结果表明:脉冲电磁处理可使YT15硬质合金刀具服役寿命增长57.2%;最佳的处理参数组合为磁通密度2T,磁脉冲个数10,脉冲电压0.8V,电脉冲组数20;磁通密度和磁脉冲个数对其寿命影响较大,脉冲电压和电脉冲组数影响较弱;脉冲电磁处理后的刀具切削力较未处理有所降低,后刀面磨损速度明显减缓。