浅析球团回转窑的设计与开发

浅析了球团回转窑的发展历程、工作原理,重点介绍了球团回转窑的筒体部、传动装置、一二挡支承装置、液压挡轮装置、窑头窑尾密封罩、结构冷却装置、窑位控制装置、测温系统、固定筛部、液压系统、干油集中润滑系统等主要组成部分的结构特点及筒体的载荷计算、弯矩计算和应力校核及轮带设计校核计算。     

氧化铝生产——熟料烧结(续)

(十一)熟料窑熟料窑的窑体是由厚20～30毫米钢板焊成的直径3.6～4.3米、长72.5米的长圆筒,筒体上套装有四道轮带(矩形或箱形),每道轮带下有一对托轮承托着,在筒体中部装有大齿圈,借传动装置的小齿轮使筒体回转。筒体内砌筑耐火砖,     

大型回转窑筒体制作精度技术方案研析

文章通过对大型回转窑筒体重要性分析,制定了筒体制作精度保证技术方案。方案中对单个筒节端面坡口加工及测量、轮带段筒节的加工及测量、段节同轴度检测方案进行了详尽的论述,保证了回转窑中关键件筒体的制作精度,为回转窑设备的正常运转奠定了基础,为今后筒体制作提供了技术保证。     

砖板衬里加压反应釜力学性能的有限元分析

本文介绍了砖板衬里加压釜的特点,分析了其工作状态下承载情况。针对一台湿法冶炼用加压釜,利用Ansys软件建立该设备筒体段的二维轴对称模型,计算了承受内压载荷与热载荷的情况下,筒体段的三向应力分布情况及变形量,并分析了计算结果。     

回转窑轮带轴向窜动的复位和调整

武钢鄂州球团厂回转窑轮带在窜动100 mm后,通过在筒体上加装液压顶和调节托轮相结合的方法,使轮带快速复位,为今后大型回转窑的检修积累了很好的经验。     

一种大型筒体加工用组合工装治具设计

本文以大型回转设备球磨机筒体加工为例,将原筒体外圆、端面、法兰轮带等卷制、吊装运输中用于定位和防治筒体变形使用的不同结构、规格的组合固定死支撑装置,通过结构设计改进及优化,设计成满足不同规格结构、规格筒体加工定位、防变形需要的可拆卸组合活支撑,应用在筒体加工过程,使用效果良好。     

混合机筒体危险截面的确定和强度校核

筒体装置是圆筒混合机的主体。由筒体、滚圈、大齿圈、筒体内附件等组成。本文分析了5B150 3.6 m×13 m圆筒混合机筒体上载荷的分布情况,确定了滚圈危险截面并根据建立的数学模型进行强度校核。     

烘干机筒体窜动分析及调整处理

3.8 m×35 m烘干机筒体多次出现上下窜动的现象,筒体窜动时常引起构件磨损,特别是对筒体轮带、拖轮组、齿轮影响非常大,也对设备的安全稳定运行构成了很大影响。本文对筒体窜动原因进行分析,并对窜动可能造成的设备事故和故障,以及曾经发生过的一系列故障进行了描述和原因分析,结合实际经验提出了调整方法。     

辊系弹性变形数值模拟与辊型优化

辊间接触压力的不均匀分布是导致支撑辊剥落的主要原因之一。利用数值模拟方法,分析了不同工况条件下的辊间接触压力分布,明确了主要工艺参数如轧制力、弯辊力等对辊间接触压力分布的影响规律,以及辊间接触压力峰值分布与支撑辊剥落带的对应关系。利用变接触支撑辊技术的思想,结合现场实际情况,对支撑辊辊型进行了优化,优化后的支撑辊辊间接触压力峰值得到显著降低,接触压力的不均匀分布也得到了明显的改善。     

变接触长度支承辊间等接触压力时轧辊变形规律

以某中板厂生产条件和数据为基础,讨论了变接触长度支承辊辊间接触压力相等时的轧辊变形情况.在不同轧制压力前提下,首先计算出轧辊辊身中点处及轧辊与轧件边部相对应点处的变形,然后再绘制出变形沿辊身的分布规律,发现压扁变形比弯曲变形大,同时当轧制压力增大时,轧辊变形随辊身长的变化率亦会增大.     

辊形配置对辊间接触压力与板形调控影响分析

为系统分析不同辊形配置下辊间接触压力分布形式与板形调控特性,以某1 800 mm热轧生产线使用的2种典型辊形配置为研究对象,建立对应的辊系有限元模型,计算不同带钢规格与调控手段下辊间接触压力分布形式,分析得出常规凸度支撑辊对应的辊间接触压力分布形式与CVC工作辊辊形呈现出明显的对应性,且压力分布形式受轧制规格与调控手段的影响明显小于CVC支撑辊。利用接触压力峰值和不均匀度表述辊间接触压力分布特征,将不同规格与调控手段对辊间接触压力分布特征的影响进行量化处理,得到更为具体的不同参量在整个变化范围内对分布特征的整体影响趋势。同时还对2种辊形配置下不同辊间接触压力对轧机板形调控特性影响进行分析,得出CVC支撑辊对应辊形配置的弯辊力与窜辊位置在板形调控能力上均强于常规凸度支撑辊辊形配置,而不同辊形配置对辊缝形状的影响表现出较为明显的差异,引入辊间接触压力边中比得到调控特性与辊间接触压力之间的具体关系,并结合现场的实际生产数据对仿真分析结果进行验证,研究结果可为现场辊形配置与板形调控提供较好的理论基础和生产指导。     

辊形配置对辊间接触压力与板形调控影响分析

为系统分析不同辊形配置下辊间接触压力分布形式与板形调控特性,以某1 800 mm热轧生产线使用的2种典型辊形配置为研究对象,建立对应的辊系有限元模型,计算不同带钢规格与调控手段下辊间接触压力分布形式,分析得出常规凸度支撑辊对应的辊间接触压力分布形式与CVC工作辊辊形呈现出明显的对应性,且压力分布形式受轧制规格与调控手段的影响明显小于CVC支撑辊。利用接触压力峰值和不均匀度表述辊间接触压力分布特征,将不同规格与调控手段对辊间接触压力分布特征的影响进行量化处理,得到更为具体的不同参量在整个变化范围内对分布特征的整体影响趋势。同时还对2种辊形配置下不同辊间接触压力对轧机板形调控特性影响进行分析,得出CVC支撑辊对应辊形配置的弯辊力与窜辊位置在板形调控能力上均强于常规凸度支撑辊辊形配置,而不同辊形配置对辊缝形状的影响表现出较为明显的差异,引入辊间接触压力边中比得到调控特性与辊间接触压力之间的具体关系,并结合现场的实际生产数据对仿真分析结果进行验证,研究结果可为现场辊形配置与板形调控提供较好的理论基础和生产指导。     

基于ANSYS的回转窑滚圈结构参数优化

针对箱形滚圈经常产生疲劳裂纹的问题，对箱形滚圈的结构参数建立优化模型，用ANSYS进行优化，使结构更加合理，内部峰值应力最小，延长滚圈的抗疲劳寿命。     

Determination of Stress Intensity Factors for a Cracked Shell under Bending with Improved Shell Theories

A formulation based on the linearized shallow shell theory has been developed by Delale and Erdogan to determine the stress intensity factors of a shell with a through-the-thickness crack. The drawback in the formulation is that the crack-face closure at the compressive edges when a cracked shell is subjected to a bending load is not taken into account, which results in the penetration of material at the crack faces. The present research is aimed to improve the formulation by including the effect of the crack-face closure on the stress intensity factors. Simulation of the closure is achieved by a line contact at the compressive edges of the crack faces. The unknown contact force is then computed by solving a mixed-boundary value problem iteratively to ensure that either the normal displacement of the crack face at the compressive edges equals zero or the contact pressure equals zero along the crack length. The results have shown that the crack-face closure significantly influences the magnitude of the stress intensity factors and tends to reduce the maximum stress intensity factor. The magnitude of the reduction varies with the curvatures of the shell and the ratio of the two curvatures as well.     

冷轧平整机板形控制特性研究

针对某1500mm四辊冷轧平整机在轧制过程中产生的板形缺陷等问题,通过建立平整机辊系弹性变形有限元模型,对其板形调控特性进行了仿真分析,分析主要包括辊形、带钢宽度、轧制力、弯辊力的变化对辊系变形及辊间接触压力的影响,由仿真结果揭示出了平整机产生板形问题的机理,对指导实际生产具有重要意义。     

Discrete Element Modeling of Contact Creep and Aging in Sand

In this study, aging in dry, clean sand induced by contact creep is investigated through numerical simulations using the discrete element method. Simulation results demonstrate that contact creep initiates the redistribution of contact forces. Although contact creep produces a very small decrease in porosity (approximately 1.7%), a significant change in the contact force distribution is produced in the aged sample. The contact forces ultimately become more uniform in both magnitude and spatial distribution. This homogenization of contact forces leads to more stable force chains and therefore produces an increase in the small-strain stiffness, early strength, and dilatancy in the aged sample. Such increases are not found in the sample prepared to the same porosity as the aged sample but without aging. This is because, in generating this sample, the contact creep is not allowed and therefore its associated contact force distribution is less homogenized compared with that in the aged sample.     

变接触轧制技术在热带钢轧机上的应用

阐述了变接触轧制技术的原理.从理论上分析了变接触轧制技术在提高承载辊缝横向刚度、增加弯辊力调控功效、改善辊间接触压力分布方面的作用.通过在宽带钢热连轧机上的长时间应用证明:变接触轧制技术可以显著改善轧后带钢的板形质量、降低轧辊消耗和增加轧制单位公里数.     

Application of the theory of rolling to rolling in the case of mill vibrations

Knowledge of the reactions of the roll gap according to variable gap geometry, especially of the roll force as a function of vertical displacement of the work rolls, is required to calculate the oscillatory behaviour of the roll stand. The basic equations describing the pressure distribution in the roll gap with variable geometry are formulated using the methods of continuum mechanics. The flattening of the work rolls is taken into account by using Hitchcock's formula. Exemplary calculations show that during vibration the tension between the stands can vanish or the neutral point can surpass the roll gap exit. Both effects may result in tearing the strip at the entry of the affected mill stand.     

Hysteresis of Capillary Stress in Unsaturated Granular Soil

Constitutive relationships among water content, matric suction, and capillary stress in unsaturated granular soils are modeled using a theoretical approach based on the changing geometry of interparticle pore water menisci. A series of equations is developed to describe the net force among particles attributable to the combined effects of negative pore water pressure and surface tension for spherical grains arranged in simple-cubic or tetrahedral packing order. The contact angle at the liquid–solid interface is considered as a variable to evaluate hysteretic behavior in the soil–water characteristic curve, the effective stress parameter χ, and capillary stress. Varying the contact angle from 0 to 40° to simulate drying and wetting processes, respectively, is shown to have an appreciable impact on hysteresis in the constitutive behavior of the modeled soils. A boundary between regimes of positive and negative pore water pressure is identified as a function of water content and contact angle. Results from the analysis are of practical importance in understanding the behavior of unsaturated soils undergoing natural wetting and drying processes, such as infiltration, drainage, and evaporation.     

Study of specific pressure during the rolling of metal powders

Conclusions The nature of the distribution of specific pressure on the contact arc of roller-metal is shown experimentally.A dependence is established for the ptessibility of powders of iron, 1Kh18N9T stainless steel and copper during vertical and horizontal rolling.An equation is proposed, describing the dependence of densification of the powder on the maximum specific pressure on the metal-roller contact arc.The dependence between the critical angle, the contact angle and the maximum specific pressure during vertical and horizontal rolling of iron powder is investigated, an increase in these angles being noted with an increase in pressure on the roller.It was established that the pressibility of powders during rolling is higher than during pressing by 10–15%.