粉末冶金齿毂开模分析与模具设计

随着我国汽车制造业的飞速发展,对汽车变速箱的要求也越来越高。同步器齿毂是汽车变速箱内的重要零件,如何生产出高精度、高质量的粉末冶金同步器齿毂是一个非常重要的课题。本文对具有代表性的粉末冶金齿毂的开模、模具设计和生产工艺进行分析,从开模、模具选材、模具结构、模具间隙、模具尺寸等方面对粉末冶金齿毂压制模具进行优化设计,提高齿毂模具使用寿命、精度和质量。     

金属冲压模具材料的新动向

冲压模具的应用范围非常广,其中包含了汽车、日用五金以及电子行业等等,属于所有模具应用中使用量最大的模具。在冲压模具的设计和制造中具备非常多的知识和技术,而且当前的很多金属冲压模具材料需要通过进口,我国自主研发的材料在数量和应用方面都呈现不足,而且还需要针对当前应用到的技术进行科学分析,结合我国实际现状进行优化,进而满足现代金属冲压模具市场发展的要求。冲压模具材料在市场中有着非常重要的地位,为了保障冲压模具能更加适应当前的市场需要,针对金属冲压模具材料进行分析,提出相应的材料发展新动向。     

几种典型铝挤压型材模具的结构设计方案

现代铝型材企业中,模具设计的合理性直接影响到挤压生产成本和效率以及产品交货周期。随着铝合金型材向大型化、复杂化、精密化、多用途方向发展,对挤压工模具提出了越来越高的要求。因此,提高模具结构设计方案的合理性成了整个铝挤压模具行业的重中之重。通过对几种较为典型的铝挤压模具的设计方案进行对比和剖析,指出优缺点,并提出正确有效的修正方法。     

铝挤压模具技术的最新研究成果及评述（2）

1.9 挤压模具的优化设计理论与技术开发挤压模具是挤压工艺过程的基础,不仅决定挤压产品的形状、尺寸精度和表面状态,而且还影响挤压成形力及产品的组织和性能.因此,挤压模具是挤压技术的关键,对挤压过程起着特殊重要的作用.而挤压模具的优化设计又是获得经济而合理的模具的重要手段,近年来,世界各国投入了大量人力、物力和财力致力于挤压模具优化问题的研究.由于大型计算机的开发和应用,CAD/CAM技术的迅速发展,有限元分析理论和实用技术的不断完善以及各种数值模拟和物理模拟方法进一步实用化,为挤压模具优化设计的     

轨交模具全生命周期管控关键环节及措施

轨道交通车辆用型材不断向“大型、宽幅、薄壁、多腔”方向发展。大型材伴随而来的是铝挤压模具越来越大、价值亦越来越高。如何让大模具物有所值、物超所值,是挤压行业高质量发展面前的一个重大课题。浅析了如何管控型材设计、模具设计、制造、服役、维护保养、挽救等轨交模具全生命周期关键环节及措施,以期提高大模具的性价比和企业核心竞争力。     

国内热作模具钢发展概况

前言 随着国内外工业技术的迅速发展和不断提高，模具的应用越来越广泛，如金属材料制品、塑料制品、陶瓷制品、橡胶制品、建材制品、耐火材料制品等大部分都采用模具成型。采用模具成型具有生产效率高、材料利用率高、降低产品生产成本等特点。目前模具钢已发展成三大系列即冷作模具钢、热作模具钢、塑料模具钢，本文仅对热作模具钢的发展概况进行阐述。     

九十年代模具技术的发展动向

本文根据科学技术的进步和工农业生产水平的发展对模具的数量和质量提出了越来越高的要求,从模具新材料的开发与应用、模具设计结构的更新与发展、模具CAD/CAM技术的发展、模具复合加工技术的开发和应用、模具自动加工系统的研制与发展、激光加工在模具制造中的应用、研磨抛光技术的发展、模具标准化的发展趋向及模具制造行业的发展动向等九个方面对九十年代模具生产技术的发展动向进行了较系统的分析讨论,得出了发展生产必须优先发展模具技术的结论。     

国内模具钢市场现况及展望

前言 模具是工业生产的基础工艺装备,是衡量一个国家产品制造水平高低的重要标志。75％的粗加工工业产品零件、50％的精加工零件由模具成型,绝大部分塑料制品也由模具成型。作为国民经济的基础工业,模具涉及机械、汽车、轻工、电子、化工、冶金、建材等各个行业,应用范围十分广泛。     

注塑模具设计关键问题

塑料件在汽车上的应用已经越来越广泛,而制件的表面质量、成型精度完全由模具决定之外,它的内在质量、成型效率也受模具的控制,但许多模具行业设计加工过程中出现大量的失误,造成成本的增加,工期的延误,所以在汽车产品更新换代极快的今天,当务之急是如何高效、快速、高质量和规范化地设计注塑模具,在本文中,我们从产品设计和模具设计经验两方面来阐述.     

国内模具钢市场现况及展望

模具是工业生产的基础工艺装备，是衡量一个国家产品制造水平高低的重要标志。75％的粗加工工业产品零件、50％的精加工零件由模具成型。绝大部分塑料制品也由模具成型。作为国民经济的基础工艺装备，模具涉及机械、汽车、轻工、电子、化工、冶金、建材等各个行业。应用范围十分广泛。     

Improvement of water slot design for beam blank casting mould

Abstract

Two-dimensional thermo–elastic–plastic creep finite element models of two beam blank moulds with different water slot designs, the large hole mould and the small hole mould, are set up and their thermomechanical behaviour is numerically investigated by means of ABAQUS software. The temperature, distortion, stress and inelastic strain range across the hot faces as well as the fatigue life of the two moulds are discussed in detail, based on which it is shown that the distributions of temperature and distortion of the small hole mould are more uniform than those of the large hole mould, and the peak temperature of the former mould is smaller than that of the later mould. However, the fatigue life of the small hole mould is shorter than that of the large hole mould. Both moulds were put into service in an industry and it is demonstrated that the quality of the product cast by the small hole mould is better than that by the large hole mould, and the service life of the small hole mould is longer than that of the large hole mould because the service life of a mould chiefly depends on the wear of its hot face, which is much shorter than the fatigue life. An improved water slot design for the beam blank mould is then proposed and it is numerically demonstrated that this improved mould is superior to the large hole mould and the small hole mould.     

智能化激活高端冲压模具市场迎来黄金期

模具是工业生产的基础工艺装备,75%的粗加工工业产品零件、50%的精加工零件均由模具成型。模具工业是高新技术产业化的重要领域,冲压生产智能控制技术发展很快,它在材料、工艺一体化的基础上,依据已有材料和工艺数据库实现冲压加工过程的在线控制或智能控制。根据我国模具产业面临迅速崛起发展智能控制的良好契机,论述了发展智能模具是制造行业高新技术的新方向,研究了冲压机械加工的设计原则与应用,提出了智能化需求推动模具产业实现快速发展,同时指出了冲压机械加工控制技术的智能化趋势。     

Optimisation of geometry of 185 × 185 mm square billet mould of Sidenor continuous casting machine

Abstract

Industrial trials conducted at Sidenor Basauri Works, and numerical modelling at Centro Sviluppo Materiali (CSM), have been combined in order to find a square 185 × 185 mm billet peripheral geometry that improves the quality of cast products by eliminating the occurrence of off corner cracks and depressions, and reducing the percentage of rejection. The idea is to change the square shape of the mould section to a new profile having a larger corner radius and outward bulging faces. Experimental trials using moulds with convex faces and larger corner radii resulted in an interesting decrease in the percentage of rejected bars. The presence of longitudinal defects has not been completely eliminated, but the adoption of moulds with larger corner radii has been demonstrated to be successful. Numerical modelling has been used to verify that the larger corner radius is the most important variable that guarantees the improved result, while it is less sensitive to different deflections of the faces. This encourages the use of moulds with flat faces, which produce billets that are much easier to handle with conventional tools for their transfer. It can be concluded that by using moulds with a corner radius of 40 mm, instead of conventional moulds with 10 mm corner radius, and flat faces, the risk of longitudinal off corner defects is significantly reduced.     

结晶器电磁制动技术的应用研究

论述了板坯连铸结晶器中应用电磁制动技术的发展、研究和应用状况。电磁制动技术可以控制结晶器内钢液面的波动,减少结晶器保护渣的卷渣,有利于结晶器内夹杂物的去除。鞍钢电磁制动的研究结果表明,电磁制动可降低液面波动50%以上,可提高目标拉速0.5m/m in。     

增材制造技术制备生物植入材料的研究进展

增材制造技术突破了传统模具加工工艺的限制,可用于高效个性化定制生物医用材料。近年来,医学上对骨骼修复和移植的个性化需求显著增加,增材制造可满足该定制化的需求,促使增材制造技术在生物医用材料领域占据重要地位。随着材料科学技术和计算机辅助技术（CAD/CAM）的发展,可用于增材制造的生物植入材料不再局限于钛系、钽系、钴铬钼等合金,聚醚醚酮、磷酸钙盐等非金属类材料因良好的生物相容性也得到了广泛应用,增材制造技术制备仿生人造骨植入体成为新的研究热点。本文介绍了增材制造技术的原理,对激光、电子束、光固化等增材制造技术进行了比较,并阐述了增材制造在生物植入体和医疗器械方面的应用现状,对增材制造技术在医疗领域的应用及发展做了展望。     

Process simulation of powder injection moulding: identification of significant parameters during mould filling phase

Abstract

Simulating and optimising the powder injection process are complex problems since a number of linked material, geometry and process variables have to be considered. In addition, it is very difficult to identify critical parameters for designing binder systems, feedstocks, parts, moulds and processing conditions owing to the fact that multiple objective functions have to be considered. Towards the goal of identifying the level of significance of various material, process and geometry parameters during powder injection moulding, a systematic procedure for sensitivity analysis has been successfully developed for the mould filling phase of the PIM process. In this sensitivity analysis, all input parameters were defined for the mould filling simulation and all output parameters for optimum design of part, mould and processing conditions and dimensionless sensitivity values for all input and output parameters were calculated, which allow parameters with different units to be compared quantitatively. The sensitivity analysis procedure developed will be an invaluable tool for both the design engineer in the PIM industry who has to determine the critical input parameters for given design targets, as well as for the production engineer who has to optimise and monitor the production stage.     

外加液态保护渣连铸生产实践与前景展望

 外加液态保护渣可以提高铸坯质量和可浇性。在某厂板坯连铸机上,分别采用液态保护渣和固态保护渣进行多钢种浇注试验,对比液态保护渣和固态保护渣消耗量、结晶器温度分布、拉坯摩擦力及铸坯质量,并对液态保护渣的应用前景进行展望。结果显示,液态保护渣比固态保护渣消耗量增加60%左右,结晶器温度分布更均匀,连铸拉坯摩擦力降低约15%,铸坯质量有所提高。这说明在连铸过程中,液态保护渣使结晶器和铸坯间传热更均匀;液态保护渣润滑效果更好,可以提高铸坯质量。同时,有望不添加F-、Na+等有害离子,改善环保问题。     

Experimental Investigation for the Hardness of Castings Produced by Using ZCast Process

ZCast direct metal casting process is one of the important techniques of additive manufacturing which is used for printing the shell moulds for casting of non-ferrous materials. In the present work, an attempt was made to experimentally investigate the effect of different control factors on the hardness of castings produced using this ZCast process. Taguchi’s design of experimental method was used to perform the experimentation. Aluminium, brass and copper alloy castings were obtained in three different sizes using 3D printed shell moulds of different wall thicknesses. The obtained results were analysed using signal-to-noise ratio and analysis-of-variance. Analysis showed that the hardness depended on the casting material and 3D printed shell mould wall thickness. Cooling curve analysis and microstructure analysis of casting obtained with mould of different thickness were also performed. Paper revealed the potential suitability of copper, brass and aluminium for producing casting using ZCast process. The present research could provide valuable data of hardness of rapid castings of different material and might confirm the effectiveness and applicability of ZCast process in foundry industry.     

Heat-flux measurements of industrial on-site continuous copper casting and their use as boundary conditions for numerical simulations

An embedded sensor, designed for rapid and accurate response times and using wireless data transmission, has been developed for the on-site measurement of temperatures in industrial continuous casting moulds. The sensor has been used to measure the temperature at several points in the mould during production in a Southwire copper casting process. The measured data has been used to calculate the temperature gradient in the mould to estimate the heat flux through it; this is then used as a boundary condition for numerical simulations of solidification. For these, we employ a method that tracks the solidification front explicitly; this has an advantage over fixed-grid methods in simulations for materials having a short solidification interval, since the release of latent heat at the solidification front can be resolved without resorting to a very fine mesh. The special considerations required for setting the initial condition for the numerical scheme and the time taken for the superheated melt to form a solid shell are also discussed.     

Modelling molten flux layer thickness profiles in compact strip process moulds for continuous thin slab casting

Abstract

The important functions promoted by powdered flux added over the liquid steel surface in continuous casting moulds are strongly affected by the thickness of the liquid layer that forms as a result of the heat absorbed. The present work discusses the results of a three-dimensional steady state model, developed to represent the coupled fluid flow and heat transfer phenomena that determine thickness profiles of the liquid flux layer. Since the laminar flow of the liquid slag layer depends on the shearing imposed on it by the turbulent motion of the liquid steel beneath it, and since additionally this motion is strongly influenced by the flow characteristics of the steel stream poured into the mould through the submerged entry nozzle (SEN), separate turbulent flow models for the liquid steel in the SEN and the mould were also developed. The consistency among the models and their accuracy was judged by comparing thickness and temperature flux profiles measured in plant against predicted ones; the comparison showed good agreement. The effects of casting speed, mould width, and flux viscosity and heat of melting on the liquid layer thickness were investigated. The last variable was found to exert the most marked influence. Different from conventional casting moulds, where the liquid layer thickness increases with increasing casting speed, in compact strip process moulds the thickness remains almost constant with increasing casting speed. This difference is well accounted for by the model, which suggests that this behaviour stems from the different slag flow patterns generated in straight, wide moulds and in thin moulds having a central upper funnel shaped section.