MECHANICS ANALYSIS ON PRECISE FORMING PROCESS OF EXTERNAL SPLINE COLD ROLLING

According to the suitable assumption, the deformation process of external spline cold rolling is analyzed. By the graphing method, the slip-line field of plastically deforming area in process of external spline cold rolling is set up. Different friction-conditions are used in different contact areas in order to realistically reflect the actual situation. The unit average pressure on contact surface of the rolling process is solved according to the stress filed theory of slip-line. And the formulae of the rolling-force and rolling-moment are established. The theoretical result is well consistent with the finite element analysis. A theoretical basis is provided for the precise forming process of spline cold rolling and the production of external splined shafts.

Rolling Force and Rolling Moment in Spline Cold Rolling Using Slip-line Field Method

Rolling force and rolling moment are prime process parameter of external spline cold rolling. However, the precise theoretical formulae of rolling force and rolling moment are still very fewer, and the determination of them depends on experience. In the present study, the mathematical models of rolling force and rolling moment are established based on stress field theory of slip-line. And the isotropic hardening is used to improve the yield criterion. Based on MATLAB program language environment, calculation program is developed according to mathematical models established. The rolling force and rolling moment could be predicted quickly via the calculation program, and then the reliability of the models is validated by FEM. Within the range of module of spline m=0.5-1.5 mm, pressure angle of reference circle α=30.0°-45.0°, and number of spline teeth Z=19-54, the rolling force and rolling moment in rolling process （finishing rolling is excluded） are researched by means of virtualizing orthogonal experiment design. The results of the present study indicate that： the influences of module and number of spline teeth on the maximum rolling force and rolling moment in the process are remarkable; in the case of pressure angle of reference circle is little, module of spline is great, and number of spline teeth is little, the peak value of rolling force in rolling process may appear in the midst of the process; the peak value of rolling moment in rolling process appears in the midst of the process, and then oscillator weaken to a stable value. The results of the present study may provide guidelines for the determination of power of the motor and the design of hydraulic system of special machine, and provide basis for the farther researches on the precise forming process of external spline cold rolling.

Online application of automatic surface quality inspection system to finishing line of cold rolled strips

An automatic surface quality inspection system installed on a finishing lineof cold rolled strips is introduced. The system is able to detect surface defects on cold rolledstrips, such as scratches, coil breaks, rusts, roll imprints, and so on. Multiple CCD area scancameras were equipped to capture images of strip surface simultaneously. Defects were detectedthrough 'Dark-field illumination' which is generated by LED illuminators. Parallel computationtechnique and fast processing algorithms were developed for real-time data processing. Theapplication to the production line shows that the system is able to detect defects effectively.

Multiaxial fatigue life prediction of kiln roller under axis line deflection

This paper investigates the multiaxial fatigue life of the roller in rolling contact with wheels with respect to axis line deflection. The multiaxial fatigue criteria proposed by Wang and Brown, together with the ralnflow counting method and Miner- Palmgren＇s rule, are applied to the cumulative damage estimation and life prediction. As the axis line deflection of overlong kilns generally results in asymmetric load distribution on each roller, the load ratio is introduced to describe the deflection for quantitative stress analyses. The stress analyses are performed within the finite element code ANSYS. The tangential friction stress is calculated in terms ：of the condition of the rolling contact area. By taking one roller as an example, the plotted fatigue life versus load ratio curve discovers how the axis line deflection affects the fatigue life. This study is significant to prevent the fatigue failure of the roller and can provide basis to adjust and optimize the axis line of the rotary kiln.

Thermal spray coating on conductor rolls in electroplating line

In electroplating lines,many conductor rolls are installed in electroplating bath.Typical electroplatings are tin plating(ETL) and zinc plating(EGL),and from required product qualities,a vertical cell for the former and a horizontal cell for the latter is often used.Generally,chrome plating or WC cermet thermal spray coating is applied to stainless steel conductor roll in ETL for prolonging service life by improvement of wear resistance and corrosion resistance.On the other hand,Hastelloy type alloy substrate is used for conductor rolls in EGL due to severe corrosion environment of electro plating solution.Thermal spray coating is effective for reducing wear,but there are many cases where the coating cannot complete expected service life when corrosion becomes an issue.In this study,thermal spray coating for ETL conductor roll and development of the coating for EGL conductor roll to meet expected service life are described.

ON-LINE INSPECTION TECHNIQUES OF MANUFACTURING QUALITY OF ROLLED-STEEL SHEET

On-line measurement of manufaturing quality of rolled steel needs the performances of noncontact, high-responds, high-resolution and high aceuracy. The reccntly developed hardware makes it possible. This paper gives a review of the development of this techniques and introduces four kinds of developed measurement systems. And the future development trends in this field was also discussed.

Slip Line Field Solution for Second Pass in Lubricated 4-High Reversing Cold Rolling Sheet Mill

The development of a possible slip line field (slf) for theoretical calculations of the deforming pressure (load) in a second pass of a lubricated cold rolling sheet mill and validation using values from an aluminium sheet rolling mill was done in this work. This will be relevant in the manufacturing industries providing an easy method for determining necessary applied rolling load. Experimental rolling was carried out to observe the shear lines in the deformation field. Construction of possible slip line field model was developed adhering strictly to assumptions of rigid plastic model. Calculation of the deforming force/load was achieved using Hencky’s equation. Results showed that the load calculations for constructed slip line field using aluminium sheet rolling as an example tallied with values obtained from Tower Aluminium rolling mill. Slip line fields constructed for the second pass described adequately the rolling pressure in the cold rolling process, giving a valid solution of the exact load estimates on comparison with the industrial load values. Roll pressure along the arc of contact rose fairly linearly from the entrance to a maximum at the exit point. This work showed that slf for the first pass in a cold rolling mill cannot be used for subsequent passes;it requires construction of slfs for each pass in the cold rolling process.

滚动球变换支持下的TIN-DDM地形特征线自动提取方法

针对传统规则格网数字高程模型地形特征线提取方法中存在阈值难以定量调控、连接方式无法自适应调整以及地形特征线类型不完整的问题,将滚动球变换模型应用于不规则三角网数字水深模型(triangulated irregular network digital depth model,TIN-DDM)地形特征线的自动提取,在构建临界滚动球半径关联的地形特征点定量识别判定准则基础上,引入地形形态边界点概念,采用逆向工程的建模思路,建立了以剖分单元为基础的地形特征线自动提取模型,结合地形类型判定准则的多尺度表达特性及顾及水深数值的地形特征优化模型,提出了可多尺度表达且类型完整的地形特征线自动提取方法。试验结果表明:相比于经典地表流水模拟方法,该方法可实现完整、连续且细分的TIN-DDM地形特征线自动提取及多尺度表达,且提取的地形特征线具有更高的地形重构精度。

基于自适应窗口与压缩幅值的瞬时转频估计

针对变转速工况下轴承信号的时频分布能量发散、噪声和谐波干扰强导致其转频难以获取的问题,提出一种基于自适应窗口和压缩幅值的瞬时转频估计方法。首先,通过自适应窗口在频率轴方向搜索出脊线窗口避免噪声和谐波的干扰;其次,在脊线窗口内用压缩幅值方法集中发散的脊线能量;然后,用惩罚函数法提取脊线,实现转频的精确估计;最后,根据采用轴承实验台收集的数据验证了所提出方法的有效性和鲁棒性。结果表明,相比于传统方法,采用所提方法估计瞬时转动频率使误差降低约8%。

大型连续绿茶精制加工生产线研发

茶叶加工技术与装备是茶叶产业发展的基础,对行业发展起着举足轻重的作用。为实现绿茶加工机械自动化生产,设计了大型连续绿茶精制加工生产线,阐述了该生产线系统结构、主要生产环节及安装调试应用。基于PLC控制的大型连续绿茶精制加工生产线,主要由鲜叶上料输送机、大型滚筒杀青机、冷却回潮机、四机协同联动式揉捻机组、并列连续预烘干机组、储料仓、计量分料装置、茶叶炒干与抛光机组、筛分装置、风选装置及配套的测控系统等组成。针对绿茶加工工艺的各个环节,采用模块化设计,根据茶叶加工企业的厂房实际情况,灵活安装组线,满足企业个性化需求。基于模糊PID温度控制的大型滚筒杀青机双模糊控制技术,解决了传统杀青温度与时间无法实现精确控制的难点问题。采用链式刮板输送智能加料装置与多机联动协同连续揉捻控制技术,实现多机协同联动式自动加料连续揉捻,边进料边揉捻,揉捻均匀度高。生产线上杀青机、理条机和烘干机各环节温度采用模糊PID控制,解决了茶叶加工温度、投叶量与杀青、理条、烘干时间实时配合的问题,输入不同等级、不同重量的鲜叶可输出相适应的杀青温度和时间,实现对茶叶生产过程的精确控制,减少人为因素的干扰,实现绿茶的智能化生产。近年来,生产线用户遍布皖、苏、浙、云、贵、川、豫、湘、鄂和陕等10多个省份200余家茶叶生产企业。该生产线的推广应用,实现了茶叶规模化生产,保证了茶叶品质,对茶产业发展具有重要意义。

浇铸温度对AZ31镁合金铸轧凝固焊合线的影响

基于φ880 mm×400 mm水平双辊铸轧机的实际工况,通过有限元模拟分析了浇铸温度对铸轧区AZ31镁合金凝固焊合线的影响规律。结果表明,浇铸温度对凝固焊合线位置影响较为明显,但对其形状影响较小。随着浇铸温度提升,凝固焊合线逐渐向出口靠近,边部Kiss点(K')和Kiss线上的凸点(K')连线与过K'点平行于铸轧方向的直线的夹角α先减小后增大。当浇铸温度为965 K时,铸轧过程中极易出现漏液,合适的浇铸温度范围为915~959 K。对比不同浇铸温度下的仿真结果,浇铸温度为945 K时,∠α最小,有利于缓解镁合金铸轧板带边裂。

基于优先权与双可变时间窗的大型热轧生产线机会维护建模

为解决大型热轧生产线日常动态维护和支撑辊定期更换带来的维护需求差异问题,综合考虑长距离条件下的维护资源及停机时间限制,引入维护优先权规则识别部件的组合维护判断次序,构建双可变时间窗规则辨别部件是否维护并区分维护需求,进而建立系统整体动态机会维护模型.实例分析表明,该模型可有效解决维护资源和停机时间限制下大型热轧生产线的差异化维护调度问题,且比传统基于时间窗的模型更具成本优势.

RTR(Roll to Roll)方式制作25μm/25μm COF精细线路的参数优化

随着电子产品小型化和液晶显示器IC封装技术的快速发展,COF(Chip on Film)技术的应用市场得到了迅速扩大。按照片式减成方法制作的线宽/线距在50μm/50μm以下的精细线路,常常会出现导线过细或断线等缺陷。论文采用目前先进的RTR(Roll to Roll)生产工艺,选用12μm铜箔、15μm干膜,使用玻璃菲林进行图形转移,并运用正交设计法对影响精细线路品质的曝光能量、显影速度、蚀刻速度、蚀刻压力等因素进行优化试验。以精细线路的线宽和蚀刻系数作为评价标准,找出最佳参数,并分析了蚀刻压力对精细线路的影响机理。将最优化参数应用到生产中,使25μm/25μm的COF精细线路的成品率提高20%。最终实现25μm/25μm的COF精细线路的小批量生产。

8Cr4Mo4V钢大尺寸轴承外圈锻造金属流线控制

为满足8Cr4Mo4V钢制轴承长寿命和高可靠性的使用要求,开展了基于流线控制的大尺寸轴承外圈锻造技术研究,提出了预锻制坯和直接辗沟成形工艺。结合有限元模拟和锻造试验优化外圈锻造工艺,合理设计制坯过程各工序的变形量,减少了鱼尾缺陷。8Cr4Mo4V轴承钢外圈锻件的金属流线演变分析结果表明,中温预热→高温加热→镦粗→开式冲孔→切底→3次扩孔(变形量40%,50%和40%)→直接辗沟的锻造工艺实现了锻造全过程的金属流线控制,对于提高航空发动机轴承的使用寿命具有重要意义。

基于电量指纹的电网线损智能治理研究与应用

线损治理是电力供给链的关键目标之一,也是促进提质增效,提升电网经济效益的基础。电网线路、台区和用户等所形成的用电特性、正常线损特性等具有各自的电量属性特征,像人类的指纹一样综合反映了各自不同的用电特征和线损特征。基于用电信息采集系统收集的用户数据和每日更新的气象温度数据,提出一种基于固定窗向量自回归温度模型的电量指纹滚动预测和诊断方法,智能分析线路和台区的线损异常,提升国家电网精准化管理水平。最后通过实验验证所提方法模型的可行性和有效性。

SVG+FC动态无功补偿装置在热轧生产线上的应用

本文以某钢厂的热轧生产线为研究对象,对该厂区35 kV母线的电能质量进行了测量分析,提出加装一套动态无功补偿装置(SVG+FC)相互协调共同补偿的技术方案。并针对该热轧生产线运行时特点,计算出了主要设备运行时系统所需要补偿的无功容量。利用仿真软件PSAF对该系统进行了仿真,结果表明该动态无功补偿装置能够对热轧生产线引起的电能质量问题进行有效治理,且补偿性能良好。

导卫装置在轧线除尘中的创新应用

介绍了在轧钢生产线充分利用导卫件对轧制过程中产生的粉尘进行抑制和除尘。导卫处于粉尘的源头,根据导卫的结构添加集尘罩,结合热湿交换、惯性碰撞、静电捕获等原理,把惯性力、电场力、重力、浓度梯度力等相耦合,结合异质成核凝结相变、外部空间流场组织、内部结构流场优化等方式,实现对蒸气及粉尘颗粒的高效脱除。

智能润滑设备在轧钢产线的应用及故障处理

介绍了智能润滑设备的结构,讲解了其机械、电器部分的主要构成部分。说明了智能润滑系统的故障类别和故障判断的步骤,讲解了故障处理的技巧。以智能润滑设备在某轧轧钢企业中的应用为实例,重点分析了几种非典型故障排查和处理方法。

冷轧双相钢HC340/590DP翘皮缺陷原因分析与工艺优化

针对冷轧双相钢HC340/590DP表面翘皮缺陷,采用显微组织观察、能谱分析等手段,明确了通卷边部点状翘皮、带尾翘皮和通卷边部翘皮三类翘皮缺陷产生的根本原因分别为冷轧轧制线辊剐蹭、热轧粗轧立辊下凸台高度尺寸偏差、炼钢铸坯边裂导致。通过冷轧工序优化双相钢拉矫延伸率和定期更换轧制线辊、热轧工序提高粗轧立辊表面质量和优化立辊压下制度、炼钢工序提高连铸机设备精度及保证二冷水喷淋状态等系列措施,有效解决了冷轧双相钢表面翘皮缺陷。

宽体压延线退火窑特点及常见问题对策

宽体退火窑是与宽体压延线相配套的退火设备,其结构与普通宽度的退火窑基本相同,但由于原板宽度较大,在壳体宽度、辊子长度、温度监控系统、电加热系统、冷却风系统和退火工艺等方面存在一些差异,对宽体压延线退火窑及常见问题进行了分析,并提出了一些对策方法,为提高宽体压延玻璃退火质量提供参考。