铝电解多功能机组工具小车结构优化设计

铝电解多功能工具小车及其中的各项工具是电解铝生产中所必需的核心部分,针对其结构的改进、优化是非常重要的,简单介绍了工具小车及其各项工具的主要功能及结构特点,重点阐述了工具小车各部分结构的改进、优化,包括工具小车运行装置轨道刷及支架、工具小车回转装置的驱动装置、下料装置检修平台、下料装置仓体、下料装置旋转装置、更换阳极装...     

B1500 HS硼钢热冲裁过程的相变和冲裁精度

为了研究热冲裁零件微观组织及尺寸精度的变化规律,采用不同的冲裁温度和模具间隙比对B1500HS钢板进行了热冲裁试验.根据冷却曲线,研究了冲裁温度对硼钢组织转变和零件力学性能的影响;根据落料件的尺寸,分析了冲裁温度和模具间隙比对尺寸精度的影响;通过观察零件的断口形貌,分析了冲裁温度对断口质量的影响.结果表明:当冲裁温度一定时,落料件的尺寸随着模具间隙比的减小而增大;当模具间隙比一定时,落料件的尺寸误差随着冲裁温度的降低出现“正—负—正”的增长波动趋势;当冲裁温度为600~650℃或750~800℃时,落料件具有较高的冲裁精度;落料件的硬度随着冲裁温度的升高而增大,当冲裁温度为650~800℃时,落料件的组织为马氏体,硬度值HV约为550;冲裁断面光亮带的宽度随着冲裁温度升高而增大.      

高强钢冲裁断面质量模具间隙敏感性分析

高强度汽车板应用越来越多,其成形边裂问题一直是研究的热点。冲裁间隙对冲压件断面质量有着重要的影响,以S550MC、S315MC和SPFH590等3种高强钢板为研究对象,以冲孔、扩孔和电镜扫描等物理试验为研究手段,分析了冲裁间隙对断面质量、冲裁力和扩孔率的影响。结果表明,对于高强钢来说,随着光亮带宽度的增加,扩孔率并不一定增加;对于S550MC来说,适当增加冲裁间隙不仅有利于降低冲裁力,且有利于提高板料的扩孔性能。     

金属薄板滚动冲裁工艺介绍

对变冲压为辊压，变平刃冲切为斜刃剪切，以达到降低口音和提高生产率的滚动式冲裁模具作介绍。     

金属薄板滚压冲裁过程数值模拟及模具参数

研究了在没有压下辊的情况下滚压冲裁过程的运动学特性,据此提出了通孔滚压冲裁模具的设计方案.在此基础上,利用ABAQUS有限元软件进行了基于Shear Failure韧性断裂准则和任意拉格朗日一欧拉自适应网格技术的45号钢薄板滚压冲裁过程有限元仿真,分析了主要参数对断面质量的影响.仿真结果表明:方形孔滚压冲裁时,前后刃口依次经历板带弯曲、凸模压入、裂纹产生和发展、断裂和凸模拔出五个阶段;滚压冲裁断面的主要质量缺陷包括断面垂直度、毛刺、塌角、压痕等;影响滚压冲裁断面质量的主要因素包括侧隙、凸模高度、辊子半径等.减小标称侧隙和凸模高度、增大辊子半径均会使断面质量提高,其中又以对断面垂直度和毛刺高度的影响更为明显.对于45号钢一类的碳钢,后刃口标称侧隙以板厚的5%-10%为宜,前刃口标称侧隙可以更小:辊子半径应以大于板厚的100-150倍为宜;在保证板材完全断裂的前提下,应使凸模高度尽量减小.      

Optimization of Fine Hydro‐Blanking

Optimization of the process of the fine hydro‐blanking is proposed. In this approach, the V‐ring indenter carved on the work piece substitutes for the guide plate that is used by the conventional fine blanking and is pressurized by hydraulic pressure. In addition, the counter force is also replaced by hydraulic pressure to produce a uniform back‐pressure by acting as the ejector. To find the final optimal solution, the Taguchi‐FE method is adopted to simulate and find the optimal factors according to the Taguchi technology. Once the optimal factors were chosen, a hybrid system that combined the artificial neural network (ANN) with the genetic algorithm (GA) is used to search and find the final optimal solution. It was observed that the V‐ring cavity on the work‐piece has the same efficacy as conventional fine blanking. In addition, the results of the experiment and finite element simulation using the optimal factors were compared. It was found that the study could achieve its stated objectives.     

基于Lemaitre模型的辊式冲裁工艺断面质量分析

为了准确表征材料变形中逐渐劣化的过程,引入考虑损伤与裂纹萌发的弹塑性本构模型.基于Abaqus/Explicit的二次开发接口,编写耦合Lemaitre损伤模型的用户子程序,根据算例验证其可靠性.通过反复加载-卸载拉伸试验并利用弹性模量变化法来获得损伤参数值.建立辊式冲裁工艺有限元模型,应用Lemaitre损伤模型来预测断面质量,并进行试验验证.分析冲裁间隙、模具磨损与板厚等工艺参数对断面质量、冲裁力及扭矩的影响.结果表明:前刃口断面质量总体上要好于后刃口,但光亮带具有一定的倾角;塌角区会随冲裁间隙增加而增大;模具磨损程度增加会导致毛刺急剧增大;最大冲裁力与扭矩会随着板厚的增大而增大.      

镀锡板开平线矫直机插入量对板形控制的影响

基于镀锡板开平线矫直机结构形式，分析了矫直机结构特点及带材矫直机理。通过建立开平线矫直机有限元仿真模型，研究带材矫直过程的变形机理，分析各矫直辊组插入量对板形质量的影响。结合带材矫直过程仿真分析规律，建立了不同规格开平线矫直机插入量参数优化表，并针对不同来料板形制定矫直参数。参数优化后，带材浪形及翘曲缺陷基本消除，实现了镀锡板开平后板形质量的大幅提升，取得了良好的实用效果。     

在多向模锻挤压液压机上的型材挤压成形研究

在实验室模拟试验和工厂工业性生产试验的基础上,阐述了在多向模锻挤压液压机上实现挤压的工艺特点,找出了分离压余的理想方法－冲切法,给出了冲切间隙的计算方法。为减小挤压型材的弯扭畸变,建立了局部挤压比、挤压带系数的概念。给出了挤压筒中心与挤压模孔型中心距离的计算方法。     

首钢落料线常见质量缺陷分析及控制措施

首钢落料线是由北京首钢股份有限公司投资建设,于2011年5月底建成投产,主要为汽车企业提供高水平的落料压力成型服务。生产线采用德国舒勒整体进口设备及自动化控制系统,压机采用伺服直驱技术,年加工能力为10万t。首钢落料生产线在生产中产品经常出现硌伤、划伤、油污、锈蚀、辊印、毛刺、波浪、弯曲、边缘损伤和尺寸超差等影响汽车企业冲压工序的质量缺陷。针对产品常见的质量缺陷进行分析,查找各种质量缺陷的成因,提出了相应控制措施,消除了各种质量缺陷,提高了产品成材率和市场竞争力。     

Immediate post-saccadic information mediates space constancy

We recently demonstrated that the perceived stability of a visual target that is displaced during a saccade critically depends on whether the target is present immediately when the saccade ends; blanking a target during and just after a saccade makes its intra-saccadic displacement more visible (Deubel et al. Vis Res 1996;36:985-996). Here, we investigate the interaction of visual context and blanking. Subjects saw a saccade target and an equal-sized distractor. During a saccade one or the other was displaced left or right. At the same time, one of the objects could be blanked briefly. Subjects reported whether the target or the distractor had jumped. The object that was blanked was more often seen as jumping (Experiment 1), regardless of which object really jumped, implying that continuously visible objects are preferentially perceived as stable. When both objects were blanked, longer blanking led to better accuracy at identifying which had jumped during a saccade. When one object was jumped and the other, stationary object was blanked (Experiment 2), the blanked object was mistakenly seen as jumping until the jump covered 50% or more of the saccade amplitude. In Experiment 3 a large continuously present texture underwent an undetected jump during a saccade, biasing judgments of simultaneous jumps of a blanked target. The results demonstrate that space constancy in normal situations is dominated by the assumption that a continuously present pattern is stable--this pattern becomes the spatial reference for the post-saccadic recalibration of perceptual space.     

30CrMo精冲钢连铸板坯高温力学性能研究

利用Gleeble-3800 热模拟机测试了30CrMo精冲钢连铸坯从1350 °C以5°C/s和15°C/s冷却至600~900°C拉伸的高温力学性能,通过扫描电镜对拉伸试样的断口形貌和显微组织进行了观察分析,讨论了各温度区域变形断裂的机理。结果表明,冷却速度增大,铸坯整体的断面收缩率减小,铸坯的热塑性降低。30CrMo精冲钢的第Ⅲ脆性温度区间在650~750°C。将二冷区矫直点入口处的铸坯角部温度提升至800°C以上可以有效避免角部裂纹发生。     

弹簧扁钢崩料原因分析及对策

针对用户反映棒线生产线生产的弹扁在下料过程中崩料问题，对产生原因进行了分析并采取相应措施，保证了冬季弹扁正常生产。     

高炉炉壳下料计算编程

高炉炉壳下料的数控火焰切割机编程数据算法突破数控中心命令极限只有8．388m及数据设置整数位须≤5的局限，实现精确切割，大大提高了工作效率．     

提高蒸硒回转窑使用寿命的措施

针对蒸硒回转窑负压波动较大、窑尾冒酸水、温度控制不稳定、窑尾下料箱腐蚀严重、使用寿命短等问题，对蒸硒回转窑采取一系列改造和维护保养措施，取得较好的效果。     

75kA铝电解槽现代化改造的工艺技术试验

介绍了采用点式下料、计算机智能控制等当代铝工业最新技术对75KA铝电解槽进行现代化改造的方案和工艺技术试验情况。     

PLC与变频器在干熄焦电机车自动控制系统的应用

主要论述了干法熄焦电机车电气自动控制的特点以及硬件配置与系统软件。并重点论述了位置控制的基本方法与实际效果。     

提高高炉料仓给料准确度的方法

为了提高高炉料仓给料准确度,提出了利用变频器控制振筛的下料速度、通过软件过程控制进行动态补偿、硬件与软件联合控制三种方法,并在泰钢高炉上应用。结果表明,料仓给料准确度提高,下料偏差由10％降低到2％。     

A robust sequential detection algorithm for cardiac arrhythmia classification

In [1] qnd [2] Thakor et al. describe a sequential probability ratio test (SPRT) based on threshold crossing intervals (TCI) for the discrimination of ventricular fibrillation (VF) from ventricular tachycardia (VT). However, in applying their algorithm to data from the MIT-BIH malignant arrhythmia database, we observed some overlap in the distributions of TCI for VF and VT resulting in 16% overall error rate for the discrimination. In this communication, we describe a modified SPRT algorithm, using a new feature dubbed blanking variability (BV) as the basis for discrimination. Using the MIT-BIH database, the preliminary results showed that the proposed method decreases the overall error rate to 5%.     

电收尘下料螺旋输送机设计计算及结构设计

根据工艺条件,进行焙烧炉电收尘下料螺旋输送机的设计计算,并设计关键部件的结构;尤其针对原有螺旋输送机存在的不足,进行轴头端座密封、下盖密封等关键部件的改进设计;同时应用有限元分析软件Pro／MECHANICA对螺旋体进行刚度及强度分析,为产品结构优化奠定基础。