弧齿锥齿轮温锻成形工艺参数分析

采用刚塑性有限元法,分别就摩擦条件、坯料温度、模具预热温度、锻压速度等对弧齿锥齿轮温锻成形载荷的影响进行了仿真分析。分析结果表明:成形载荷随摩擦因数的增大而升高,随坯料温度、模具温度、锻压速度的升高而降低,且坯料温度较模具预热温度对成形载荷的影响更为显著。模拟结果可为弧齿锥齿轮温锻成形过程的模具设计、工艺方案制订等提供依据。     

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。     

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%。     

气门顶杆冷挤压过程模具磨损研究

通过分析零件的结构特点,基于气门顶杆的零件图设计出挤压件图。通过Archard磨损模型分析了模具磨损原因。利用DEFORM-3D的数值模拟功能分析了摩擦因数、成形速度和模具硬度对冷挤压成形过程中模具磨损的影响。结果显示:摩擦因数越低,磨损量越小,为了节约成本和简化润滑过程,选择摩擦因数接近0.1的模具磨损量较小且满足工艺要求;成形速度在30mm/s时,凹模磨损量最小,凸模磨损量较低;模具硬度增高,磨损量减小,模具硬度在接近60HRC时磨损量较小且性能稳定。数值模拟的结果为实际生产中加工工艺参数的选取提供了一定的理论指导。     

基于中频感应加热的热滚轧弧齿锥齿轮小轮工艺参数优化

基于有限元软件Deform-3D,建立弧齿锥齿轮小轮感应加热的电磁-热耦合数值模型,采用正交实验法对影响弧齿锥齿轮小轮"突耳"缺陷的初轧温度、摩擦因数、模具进给速度和轮坯转速关键工艺参数进行优化。选出最优工艺参数组合为:初轧温度950℃,摩擦因数0. 1,进给速度0. 2 mm/s,轮坯转速30 r/min。优化后,当滚轧成形过程进给3 mm时,突耳高度比例为20. 33%,对最优参数组合进行数值模拟验证,结果良好,为进一步的弧齿锥齿轮小轮滚轧成形实验开展提供了参考。     

基于修正Archard理论的螺旋锥齿轮锻造模具寿命预测

基于修正的Archard理论,采用弹塑性有限元模型对螺旋锥齿轮热锻成形的模具磨损进行了模拟仿真,分别从齿模齿顶的过渡圆弧半径、模具热处理硬度、模具的预热温度以及锻造成形速度四个方面对模具易磨损位置的磨损量进行计算,采用正交试验优化设计方法分析各工艺因素对模具寿命的影响规律,确定最优的工艺参数进行锻造试验。试验结果表明,使用提出的预测模具寿命的方法估算的模具寿命与试验结论具有较好的一致性。     

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。     

基于Deform的精冲模具磨损特性研究

建立精冲模具磨损有限元分析模型,采用有限元软件Deform 3D 对常温下的精冲凸模磨损进行仿真分析,研究模具材料的硬度、毛坯与模具间摩擦因数和成型载荷等工艺参数对模具磨损的影响。结果表明：凸模边缘的磨损严重,而侧面的磨损量较小;最大磨损深度随着模具材料硬度的增大而减小,随着摩擦因数的增大而增大;反顶力也是影响对凸模磨损的重要因素,最大磨损深度随着反顶力的增大而增大。     

螺旋锥齿轮锻造工艺与碳排放模型研究

针对螺旋锥齿轮的开式模锻工艺,系统研究锻压速度、模具预热温度、坯料温度以及摩擦系数4个工艺参数对成形过程中成型载荷及碳排放的影响,建立基于响应面法的碳排放二次回归模型,进行了仿真分析.结果表明,坯料温度对碳排放的影响最大,摩擦系数和模具预热温度影响次之,锻压速度对碳排放量几乎没有影响.     

基于热力耦合的模具型腔温升影响因素分析

研究摩擦因数、挤压速度和挤压锥角对模具型腔表面温升的影响,可以指导模具设计,同时为建立挤压成形过程中接触表面的温升模型奠定基础。考虑挤压成形过程中坯料的塑性变形和坯料与模具之间的剧烈摩擦与挤压模具型腔表面温升之间相互影响的工作特点,基于弹塑性力学、传热学和有限变形理论,建立挤压成形热力耦合弹塑性有限元分析模型。采用MARC软件对该模型进行热力耦合分析,研究摩擦因数、挤压速度和挤压锥角与模具型腔表面温升的关系。分析结果表明：锥角一定时,摩擦因数从0到0.1逐渐增大时,模具型腔温升随挤压速度的增加是先减小后不变再增加;挤压速度恒定时,温升随摩擦因数和锥角的增加而升高;固定摩擦因数时,挤压速度和锥角增大时,温升也增加。     

PCBN刀具的磨损机理和干切削GCr15时的磨损与寿命

研究了PCBN刀具的磨损机理和磨损形式。通过对干切削GCr15轴承钢时刀具的磨损形式及寿命进行试验研究 ,得出了工件硬度、切削速度对PCBN刀具磨损的影响规律以及工件硬度在临界硬度附近时刀具磨损速度最快的结论。加工两种硬度工件时的刀具寿命方程表明 ,切削速度对PCBN刀具寿命的影响小于对硬质合金及陶瓷刀具寿命的影响。     

A study on life estimation of hot forging die

In this study, the forging die life was investigated using fatigue life and wear quantity, which are generally considered for estimation of die life. The main aim is development of the equations to adapt finite element analysis to life estimation for a hot forging die. The Archard’s model was used to estimate the wear life of the die and Goodman’s and Gerber’s equations, using the stress-life method, were applied to estimation of the fatigue life. These techniques were applied to die life estimation for the hot forging die of a ball joint socket used in an autovehicle system. Rigid-plastic finite element analysis was first carried out for the forging process of the ball joint socket and then the elastic stress analysis was performed for the die in order to obtain fundamental data for the prediction of fatigue life. The die stress analysis requires the deforming loads of the workpiece to be translated into the contact loading of the die. In this case, the size of finite elements of the die and the workpiece is important for good interpolation of the loading. Therefore, the influence of element sizes on the interpolation results of the contact loading was also investigated. The wear volume of the die was measured using a 3-dimensional scanner of probe type. It was found that the measurement had a good agreement with the results of the finite element analysis for the die life estimation.     

PCBN刀具切削GCr15淬硬轴承钢时刀具磨损的研究

通过切削实验，研究了PCBN刀具切削淬硬轴承钢时刀具磨损形态及磨损机理。实验表明。PCBN刀具前刀面的磨损为月牙洼磨授，后刀面的磨损为机械磨损，其磨损程度与工件硬度呈非线性关系，并随着切削速度的提高磨损量减少。     

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.     

WEAR AND LIFE OF PCBN TOOLS WHEN DRY-CUTTING BEARING STEEL GCr15

The wear forms and reasons of PCBN tools when dry-cutting bearing steel GCr15 are studied systematically. The effect law of the workpiece hardness on PCBN tools is gained and tool wearing with the quickest speed at the workpiece critical hardness is proved. The life equation at two kinds of workpiece hardness demonstrates that the effect of the cutting speed on the PCBN tool life is less than that of carbide tools and ceramic tools.     

3D FE modelling of contact pressure response in cold rotary forging

Investigating the contact pressure response in metal forming is significant for effectively predicting the die wear and controlling the metal flow of the workpiece. This paper is aimed to utilize FE methods to reveal the contact pressure response in a complicated metal forming technology of cold rotary forging. For this purpose, a 3D FE model of cold rotary forging is first developed. Then, the contact pressure is numerically calculated. Finally, the effect of the process parameters on the contact pressure response is revealed. More importantly, the relationship between the contact pressure response and metal flow of the workpiece is clarified.     

GCr15及G20CrNi2Mo轴承钢高温润滑条件下摩擦磨损性能

为了探究轴承钢在高温润滑条件下的摩擦磨损性能,采用扫描电子显微镜(SEM)、X射线衍射仪(XRD)、洛氏硬度计等对GCr15高碳轴承钢和G20CrNi2Mo渗碳轴承钢组织、物相及硬度进行了表征,利用QG-700型气氛高温摩擦磨损试验机研究轴承钢材料不同条件下的高温润滑摩擦磨损性能,并分析其磨损机制.结果表明:2种轴承钢...     

金属塑性成形技术研究

金属塑性成形过程的选择和实施与材料,成形件的几何形状、过程的实施条件(压力、温度和速度等)密切相关。根据金属塑性变形的特点,在机械制造中常用锻造的方法来生产各类高强度、南韧度的毛坯或半成品,常用的锻造方法有自由锻、模锻和胎模锻造。本文介绍金属塑性成形中的自由锻造部分。     

Wear behaviour of forging steels with different microstructure during dry sliding

Sliding wear behaviour of two types medium carbon microalloyed steels containing various microstructures was investigated on a 320 mesh SiC paper at a sliding speed of 0.33 m/s with a load of 6 N and sliding duration of 4 min under dry sliding conditions (the sliding distance, 80 m). The experimental results showed that the different microstructures cause a great influence on the wear resistance performance of the steels. Water quenched samples with martensite structure have the highest hardness and wear resistance performance. That is because, water cooled samples contained higher amount of carbon in the solid solution. On the other hand, air or sand cooling from forging temperature results in a decrement of hardness and wear resistance in steel-1 and steel-2. However, air cooled samples showed slightly higher wear resistance than sand cooled samples due to finer grain sizes and the larger pearlite and/or precipitation contributions.