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.

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.

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.

Bending and Rolling Shear Properties of Cross-Laminated Timber Fabricated with Canadian Hemlock

In this paper,bending performance and rolling shear properties of crosslaminated timber(CLT)panels made from Canadian hemlock were investigated by varied approaches.Firstly,three groups of bending tests of three-layer CLT panels with different spans were carried out.Different failure modes were obtained:bending failure,rolling shear failure,bonding line failure,local failure of the outer layer and mixed failure mode.Deflection and strain measurements were employed to calculate the global and local modulus of elastic(MOE),compared with the theoretical value.In addition,a modified compression shear testing method was introduced to evaluate the rolling shear strength and modulus,compared with the results from strain measurements in bending shear tests.According to testing results,bonding line failure and rolling shear failure were dominant failure modes in bending tests,and the theoretical value of bending property was beyond the average level of the calculating results obtained from both deflection and strain measurements.In addition,the rolling shear strength and modulus obtained from compression shear tests were relatively smaller than those from bending tests.

Life prediction for rolling contact fatigue crack initiation of kiln wheels

This paper investigates the rolling contact fatigue of kiln wheels with respect to the axis line deflection, which is linear with the applied supporting loads on wheels. Fatigue crack initiation criteria for elastic shakedown, plastic shakedown and ratcheting material responses are applied to assess wheels responses with two sets of axial line deflection. The finite element simulations are performed by using the bilinear material mode for nonlinear and kinematic hardening in ANSYS 11.0. By comparing the results from different critera, it is showed that the low-cycle fatigue is the predominated failure. Results from different axial line deflections indicate that the optimum adjustment can greatly enhance the whole life of the supporting structure.

Three-Dimensional Analysis of Rolling by Twin Shear Stress Yield Criterion

Using the twin shear stress yield criterion, the surface integral of the co-line vectors, and the integration depending on upper limit, Kobayashi＇s three-dimensional velocity field of rolling was analyzed and an analytical expression of rolling torque and single force was obtained. Through redoing the same experiment of rolling pure lead as Sims, the calculated results by the above expression were compared with those of Kobayashi and Sims formulae. The results show that the twin shear stress yield criterion is available for rolling analysis and the calculated results by the new formula are a little higher than those by Kobayashi and Sims ones if the reduction ratio is less than 30%.

Application of WC cermet sprayed composite coating in hot-dip galvanizing lines

With the rapid development of the automobile industry, the use of galvannealed and galvanized steel sheets in automobiles is on the rise. These sheets must meet very high surface quality requirements. The surface treatment of line rolls is known to have a great impact on strip quality. To prevent dusts such as zinc ash from pressing into the strip surface, we used a composite thermal spray surface treatment technique to treat rolls. The successfully developed tungsten carbide （WC） ＋ Ni-P composite plating technology improved the quality of the tungsten carbide thermally sprayed WC roll surface. This technique is also helpful to control defects such as adhered foreign materials in hot-dip galvanized automobile outer panel surfaces.

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.

Application of innovative technologies in the strip rolling mill field

Many new types of rolling mills have been studied and developed corresponding to the needs of improvement in productivity and quality.This presentation reflects back at some of the innovative technologies,which were developed by Mitsubishi-Hitachi Metals Machinery,Inc.(hereinafter referred to as M-H),including the evolution of the pair cross mill,mill stabilizing device,on-line roll profiler,shape meter for hot-rolling,endless hot-rolling, recent application of UCM,and M-H split housing type 20-high mill.

STUDY ON CONTACT CHARACTER OF ROLLING CONE WORM GEARING AND ITS PARAMETER REASONABLE OPTION

A new type of worm gearing, rolling cone enveloping worm gearing possessing high virtues of transmission, is presented. With theoretical deduction, numerical calculations and parameter analyses, the effect of prime parameters to the character of instantaneous contact line are obtained. The ranges of the main parameters are selected reasonably. It provides the theoretical basis for the structure design and application of this new type of worm gearing.

基于物料延期干扰管理的飞机装配线动态调度

为了提升飞机装配过程中应对物料供应延期干扰的能力,对物料供应延期情况下飞机装配线动态调度问题进行研究。通过对物料交付确定性和预测性两类信息的分析将作业分为四类进行调度决策,建立了基于时间和事件混合驱动的周期性滚动调度框架和对应的数学优化模型。针对该问题设计了一种改进离散粒子群算法,将Levy飞行和离散化解码机制嵌入算法,滚动求解调度模型。数值实验结果表明,本文提出的调度方法能充分利用物料供应信息,在确定本阶段决策的同时前瞻性地进行预测决策,相比于其他动态调度方法,该方法能更有效地应对各类物料供应干扰,满足飞机装配动态调度的需求。

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。

Construction of SSR Linkage Map and Analysis of QTLs for Rolled Leaf in Japonica Rice

Genetic analysis of rolled leaf is important to rice ideotype breeding. To detect loci controlling rolled leaf of japonica restorer lines, SSR marker genotypes and phenotypes of flag leaf rolling index （LRI） were investigated in Xiushui 79 （P1, a japonica rice variety）, C Bao （P2, a japonica restorer line） and 254 recombinant inbred lines derived from the cross between P1 and P2 , and in two environments. A genetic map of this cross was constructed, QTLs for LRI were detected and their interactions with environments were analyzed. Among 818 pairs of SSR primers, 90 primers showed polymorphism between P1 and P2, and 12 markers showed highly significant correlation with LRI in both environments based on single marker regression analysis. The genetic map containing 74 information loci has a total distance of 744.6 cM, with an average of 10.1 cM between two adjacent loci. Three QTLs （qRL-1, qRL-7 and qRL-8-1） were detected with two softwares： WinQTLCart 2.5 and QTLNetwork2.0. qRL-8-1 was a new locus, accounting for 15.5% and 12.8% of phenotypic variations in the two environments, respectively. The phenotypic variation explained by additive effect was 6.6%. No interaction was found between qRL-8-1 genotype and environments.

Formation of X-120 M Line Pipe through J-C-O-E Technique

The line pipe forming operation can be divided into two parts, first is to achieve the required shape in terms of curvature and ovality after formation of the line pipe. The curvature and ovality ultimately effects the final dimensional controls at the later stage i.e. after mechanical expansion of the line pipe. The second part is to make right welding joint geometry to make the final long seam weld of line pipe. The welding joint geometry ultimately controls soundness of final seam weld at later stage i.e. during submerged arc welding of the line pipe. As far as curvature or shape of line pipe is concerned, important operation is making the required curvature along the edges of TMCP and ACC (Thermo mechanical controlled processing and accelerated cooling process) plate for line pipe (Plate Edge Crimping press) up to the 150 mm in width minimum and forming of the line pipe at J-C-O press. The selection of dies with proper hardness and curvature in both the operation plays a vital role in the formation of line pipes. The main parameters of selection dies (Tools) are size of line pipe for which dies/tools are to be made i.e. the diameter of line pipe, thickness of line pipe and most important is grade of line pipe (Strength level). The grade or strength level decides amount of spring back behavior of the steel Plate. The spring back behavior again varies from steel mill to steel mill in the same grade of HR plate. This is because the each steel mill has its own manufacturing procedures to produce the TMCP and ACC plate. The plate for line pipe is produced through TMCP (Thermo mechanical controlled processing) and accelerated cooling process. In this process the strength level is achieved by the chemical composition of the slab, thickness of the slab, reheating temperature, roughing temperature at which reduction in the thickness, finish rolling temperature and finally the accelerated cooling temperature rate.

B级钢Φ180mm连铸坯中心缩孔对Accu-Roll轧制的168mm×7mm钢管质量的影响

对192.39 t中心缩孔≤2级的B级钢(0.20%C)Φ180 mm铸坯进行了用Accu-Roll轧管机轧成693根168 mm×7 mm钢管的工业性试验。结果表明,钢管成材率为90%,内表面没有折叠、离层、裂纹等缺陷,15 MPa5 s水压试验后没有出现漏水,每根钢管通过GB/F5777-1996标准人工缺陷深度等级C12.5超声波探伤检验合格。

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。

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。