具有双层结构的烧结机台车栏板的研究

台车栏板是烧结机的主要部件之一,为了克服当前烧结机台车栏板寿命低、易变形开裂等问题,研究开发了一种具有双层结构的台车栏板。该台车栏板分为外侧的栏板本体和内侧的隔离板,可有效降低栏板热应力水平,明显提高栏板的寿命,对钢铁厂的经济效益和社会效益均具有重要意义。     

烧结机台车用铸铁材料的应用现状及展望

台车是烧结机的主要组成部分,而篦条则是台车重要的消耗备件之一。结合烧结机台车篦条的工作条件与失效过程,对台车用各种铸铁材料的特点、应用现状及组织性能进行了分析和对比,并且探讨了其未来的发展趋势。     

预防台车故障的措施及应急方案

经对烧结机台车运行故障不断进行分析研究和经验总结,我们摸清了各种事故的现象与发生原因之间的内在关系,并制订和完善了应急方案及防范措施,从而大大减少了台车运行故障对烧结机作业率的影响。     

400m^2烧结台车制造工艺的改进

烧结台车是烧结机系统的主要设备，它直接决定着烧结矿的质量。本文从烧结台车加工和装配环节分析，对图纸和工艺进行了改进与完善。     

不锈钢90m~2烧结机台车及隔热垫改造初探

烧结机台车和隔热垫能为提高烧结矿产质量提供保证,在烧结车间起到很关键的作用。文章结合唐山不锈钢烧结一车间1#、2#烧结机的目前使用情况,分析了出现隔热垫脱落引起篦条大面积脱落问题的原因,给出了改造的技术方案,得出了较好的经济效益和社会效益。     

偶数齿烧结机星轮的齿形优化

烧结机是烧结厂的主体设备，星轮作为其关键部件之一。其作用是推动整个台车     

固体自润滑轴承在烧结机台车上的应用

简要介绍了固体自润滑轴承的工作原理，制备过程及安装工艺，该技术在烧结机台车上使用后，大幅度减少了台车的维护量，降低了生产成本，取得了良好的经济效益。     

烧结燃料粒度攻关实例分析

四辊破碎机和对辊破碎机是钢铁厂的烧结燃料破碎设备。当燃料粒度达不到工艺要求时，原料出现偏析，不但造成烧结矿过烧而且对设备造成严重损坏。邯钢新区设备动力部着眼于各指标表象，分析指标变化原因，并牵头炼铁厂与设备动力部联合对烧结矿燃料粒度攻关，成功解决了烧结机台车蓖条、隔热件严重烧损、废气温度过高造成的各种问题。     

浅谈大型龙门吊多传动行走及同步纠偏的方案实施

大型龙门吊多传动行走机构采用了独立驱动及双重同步纠偏保护。本吊车自重8000余吨，考虑到轮压承重问题，刚柔腿分别设计了32组及28组行走台车，以均衡每组台车的承重载荷，降低轮压，每组台车独立驱动。     

环式冷却机打滑跑偏故障分析及处理

环式冷却机在整套烧结设备之中发挥着重要的作用,看似辅助实则必须,一般与烧结机配套进行工作,共同组成热烧结矿冷却设备,该设备的主要组成部件为:回转台车、密封装置、驱动装置、给料溜槽、卸料装置、鼓风系统、支承轨装置、侧轨定心装置、曲轨装置、润滑系统及其他附属设备。环式冷却机的故障率自投产以来高居不下,对烧结机生产效率形成了严重的制约。本文就环式冷却机打滑跑偏故障进行详细的分析,并提出几点处理建议性措施,望对环式冷却机运行安全性的提高起到一定的促进作用。     

An Investigation on the Cracking of Pallet Side Walls at a Sinter Plant

A failure analysis on the cracking of pallet side walls of a sintering machine in an integrated steel plant is presented. The pallets moving at a constant speed carry the base mix for sintering and enter an ignition hood furnace (temperature????1150°C) at a regular interval of time. The pallet side walls of a sintering machine are therefore subjected to continuous thermal cycling. The material of the pallet side wall is spheroidal graphite (SG) cast iron. Ten cracked side walls are collected and analyzed. The failure investigation involves field visit, visual observation of the cracked side walls, fractography, chemical analysis, microstructural characterization, tensile and impact tests. Most of the cracks are observed between the bolt?Chole locations of the lower side walls; bolt?Chole locations act as obstructions to thermal movement of the casting. The chemical analysis shows higher level of sulfur while the materials must be of higher purity for SG iron. Fractography shows predominantly intergranular fracture. Examinations of microstructures at the cross sections of the samples show the presence of primarily intergranular cracks. Matrix structure reveals pearlite along with ferrite surrounding the embedded graphite nodules. The amount of pearlite in the matrix is measured around 30?C35% whereas predominantly ferrite matrix is desirable at the elevated temperature application. Determinations of tensile and impact properties exhibit low values of elongation (10%) and impact energy (7?J), respectively, indicating poor toughness properties of the casting. The presence of pearlite and lower amount of graphite nodules deteriorate the thermal conductivity of the casting, thereby generating more thermal stress. The analyses show that the pallet side walls start cracking under cyclic high thermal stress due to embrittlement because of improper material.     

Reliability analysis of a flexible manufacturing cell

In this study, mathematical models are developed to study and compare the operations of a fully reliable and an unreliable flexible manufacturing cell (FMC), each with a flexible machine, a loading/unloading robot, and a pallet handling system. The operation times, loading/unloading times, and material handling times by the pallet are assumed to be random. The operation of the reliable cell is compared to that of an unreliable cell with respect to utilization of the cell components, including the machine, robot, and pallet handling system. The unreliable cell is assumed to operate under random (machine and robot) failures with constant failure rates for the machine and the robot. The pallet handling system is assumed to be completely reliable.     

顶捆穿箭式托盘捆扎机头设计

目的针对国产托盘捆扎机高端产品少、捆扎速度慢等实际状况,开展高性能顶捆穿箭式托盘捆扎关键技术的研究。方法借鉴国内外的研究经验,提出顶捆穿箭式托盘捆扎机的设计方案,分析捆扎机的工作原理,重点分析捆扎机头的工作原理与传动系统。基于PLC和凸轮组协同控制的原理,设计捆扎执行机构的工作循环图,基于Ansys开展强力捆扎组件的优化设计。结果捆扎机头仿真分析的最大应力为128.34 MPa,最大变形为0.266 mm,满足机构设计的强度和精度要求。结论研发出了高性能的顶捆穿箭式托盘捆扎机,能在企业生产中实际应用。     

THREE DIMENSIONAL PALLETIZATION OF MIXED BOX SIZES

The pallet loading problem has historically been addressed in two-dimensions by attempting to maximize the pallet area utilized in each loading layer. This paper investigates a constrained version of three-dimensional pallet loading problem with mixed box sizes. This loading method allows many boxes of various sizes to be placed onto the same pallet. A restriction is placed on the number of boxes of each size that can be loaded. The modeling procedure presented converts the three-dimensional pallet loading problem into a standard mixed 0-1 integer programming model. The solution procedure for the formulated model is also described.     

A Combined Approach to the Pallet Loading Problem

In this paper the two-dimensional pallet loading problem is considered: that is, the problem of loading a rectangular pallet of size L by W, drawing from a set of n rectangular boxes. The objective is to maximize the area covered on the pallet by the boxes loaded. The problem is approached using a combination of dynamic programming and heuristics. The structured solutions resulting from the application of the dynamic program have two serendipitous characteristics: any item may be placed on the periphery of the pallet for easy access, and some control may be retained over the center of gravity of the pallet. Computational results are given.     

A case study on the fracture of sinter machine pallet axles

A sinter machine produces sinter at 1200–1400 °C to supply raw materials for blast furnace ironmaking. The sinter machine is composed of a series of pallet cars which are constrained on rails. Each pallet car has four axles which connect the pallet car and four running rollers. In sinter production, the pallet axles experience periodic thermal expansion and periodic load changes under high temperature, high moisture, corrosive atmosphere and heavy dust. After serving for about seven years, pallet axles of one of ArcelorMittal sinter machines started breaking, causing unscheduled production delay. The fracture of the axles is in the orientation of top and bottom, and the cracks are deeper in upper portions than in lower portions of axle cross sections. The axles have been studied through chemical analysis, strength analysis, stress analysis, lifetime analysis via deterministic mechanics and lifetime distribution analysis. It has been found that the axles are breaking in fatigue-crack mechanism. The fatigue cracks are resulted from effect of thermal expansion on net tensile stress of the axles. Considering harsh working environment and dynamic loading, lifetime analysis, using deterministic mechanics, indicates that originally installed pallet axles are approaching the end of their lifetime. Weibull distribution function can very well describe lifetime distribution of pallet axles. Accordingly, about 50% of originally installed axles will be gone before next two and half years, and more than 90% of them will break before next six and half years. An intelligent replacement strategy is recommended. In a scheduled maintenance time, carefully inspect all axles using ultrasonic crack detectors, and replace those axles whose expected lifetime is shorter than next scheduled maintenance date. To replace steel SAE 1045 with steel SAE 4040 for fabricating new pallet axles may significantly increase lifetime of the new pallet axles.     

基于托盘应用状况的托盘结构创意设计

目的 研究并解决托盘尺寸与应用场景不匹配的问题。方法 对金属材料托盘结构进行创意设计,根据使用场景的不同要求,可以在原有托盘尺寸的基础上,改变托盘的长或宽,能够衍生出各种不同规格的托盘。结果 托盘尺寸可变设计能很好地解决托盘应用存在的问题,提高托盘应对不同场景的适用性,增强托盘与存储的货架、搬运的产品和运载工具等的匹配性,提高托盘的标准化程度,有利于建立托盘循环共用系统,提高托盘利用率,提高物流作业效率,降低物流成本。结论 尺寸可变设计金属材料托盘具有较好的承载性和安全性,有着良好的市场前景。     

一种半自动纸箱包装机机械系统设计

目的针对目前快递行业中纸箱包装存在的效率低、人工耗费高等问题,以350 mm×230 mm×190 mm标准邮政纸箱为研究对象,设计一种半自动纸箱包装机。方法该包装机的机械系统由托盘转动机构、开箱成型机构和折叶折曲机构组成,通过这三大机构实现纸箱的折纸包装。结果开箱成型机构实现了纸箱的开箱、成型,折叶折曲机构实现了纸箱短叶、长叶的折合,托盘转动机构保证了包装过程中各工序之间运动的连续性。结论该包装机能够在保证包装质量的前提下,大幅度提高包装效率、降低包装成本。     

Computer-aided set-up planning for machining centres configuration

One of the key issues in defining the optimal configuration of a machining centre is the problem of determining the minimal number of set-ups for the part types to be machined. This paper proposes a method to define near-optimal set-up plans for prismatic workpieces when multiple parts can be mounted on the same pallet. Set-ups are determined taking into account the accessibility of the machining directions of the workpiece and the technological constraints among the required operations. The technological constraints are divided into three types: constraints that force the operations to share the same set-up, precedence constraints that cannot be violated in the sequence of set-ups, and constraints that translate technological preferences and that might be sacrificed to optimize the set-up plan. The technological constraints are analysed with a graph-based approach. The method proposes a solution for three-, four- and five-axis machines. The set-up plan for three axes is the starting point to determine the solutions for four- and five-axis machines: the set-up plan for four and five axes results from the combination of set-ups of the three-axis machine. Alternative solutions with the minimal number of set-ups are determined. Each solution specifies the orientation of the workpiece on the pallet fixture in each set-up, the operations to be executed in each set-up and the precedence relations among set-ups. Starting from the results of the set-up planning, the configuration of the pallet can be defined and taking into account the pallet configuration, the optimal machining centre for specific manufacturing needs is selected.