低压铸铝合金车轮充型过程数值模拟的研究

利用数值模拟技术，对低压铸造铝合金车轮的流动，流型过程进行了分析，应用表明，流动场数值模拟技术可以跟踪液态金属的充型形貌，分析各部位的压力分布，为优化铸造工艺、改进模具设计提供了有效的手段。     

充型过程流场数值模拟研究

对充型过程进行分析,确立了充型过程数值模拟的数学模型。利用计算机数值模拟技术对充型阶段的流动过程进行了计算。在此基础上开发了流场模拟软件,并对铸件进行了模拟,结果证明所建立的数学模型及开发的程序是正确的。     

盘体类零件低压铸造过程的ANSYS数值模拟

在低压铸造成形过程中,液态金属流体的充型和凝固是其中最核心和最重要的两步流程,其工艺水平将决定铸件的成型质量和成品率,而且铸造过程中所产生的各类铸造缺陷大都来自于这两个阶段。本文将对盘体类零件低压铸造的充型和凝固过程进行计算机数值模拟,介绍其理论基础,并将温度场数值模拟技术和流场数值模拟技术耦合仿真,运用ANSYS有限元软件中的CFD流体仿真模块和Thermal模块,对盘体类零件低压铸造充型和凝固过程中的流场和温度场变化进行研究。     

产品荟萃

该系统是分析和优化铸造工艺的重要工具,是华中科技大学(原华中理工大学)经十数年研究开发,并在长期的生产实践中不断改进、完善起来的集成软件系统。 它以铸造充型过程、凝固过程数值模拟技术为核心对铸件进行铸造工艺分析。可以完成多种合金材质(包括铸钢、球墨铸铁、灰铸铁和铸造铝合金等)、多种铸造方法(砂型铸造、金属型铸造、压铸、低压铸造、熔模铸造等)下铸件的凝固分析、流动分析以及流动和传热耦合计算分析。在预测铸件     

低压铸造薄壁板件的流动与传热耦合数值模拟

采用 VOF法处理自由表面 ,达西源项法处理固 -液两相区流动 ,开发了铸造过程流动与传热耦合数值模拟软件。通过对流场及温度场分别采用不同的计算域和时间步长 ,大大提高了计算效率。利用该软件模拟了一薄壁板件的低压铸造过程 ,并进行了实验验证。数值模拟结果表明 ,对薄壁件而言 ,充型过程的流动对铸件初始温度分布影响较大 ,但充满后的残余流动对温度分布影响较小     

柱塞泵盖铸造工艺及数值模拟应用

通过对柱塞泵盖液压铸件结构分析,预先设计方案模拟比较确定铸造工艺方案,运用数值模拟进行充型模拟和凝固模拟,预测铸造过程中的铸造缺陷。通过对充型及凝固过程的可视化分析,进行工艺优化,根据优化工艺实际制作模具浇注铸件验证。通过使用数值模拟为薄厚不均匀液压球墨铸铁铸件的开发提供理论依据和实践指导,缩短新产品开发周期、降低开发成本。     

离心力场下铸造充型行为数值模拟

建立了离心力场下铸造充型流动的数学模型,采用VC++语言自行编制了离心力场铸造充型及凝固传热的计算机模拟软件。通过模拟旋转圆柱容器中的液体从重力静止水平自由表面状态过渡到离心抛物面自由表面的动态变化过程,并与理论解析曲线对比,以及钛合金薄壁件离心浇注充型状态与试验结果的对比,检验了所建立的理论模型及计算程序的正确性。通过对钛合金薄壁铸件在重力场与离心力场浇注工艺条件下合金熔体充型行为数值模拟结果的对比表明,在一定转速条件下,金属液的离心浇注比重力浇注具有强得多的薄壁充型能力。     

工作站环境下充型凝固过程数值模拟技术的研究

铸造充型凝固过程的数值模拟已成为铸造领域最热门的研究课题之一。目前,凝固过程的温度场数值模拟及缩孔缩松预测已应用于实际生产,充型,热应力,微观组织等基础研究及实用化进程亦取得很大进展。     

基于INTECAST软件的铸造工艺优化设计

通过应用INTECAST铸造数值模拟软件对充型和凝固过程的模拟仿真,实现了铸造工艺的优化设计。同时应用多个实例介绍了INTECAST软件进行铸造过程模拟的基本原理和过程。     

半固态铸造技术研究的进展

半固态铸造是一种新的材料成形技术 ,采用半固态铸造技术成形可以实现产品的低成本、高产出及高质量。本文着重介绍了半固态铸造合金的坯料制备和成形方法 ,同时分析了搅拌速度和金属液冷却速度对一次相的影响 ,还对半固态合金微观组织的形成和演化以及充型过程数值模拟等进行了分析 ,提出了发展半固态铸造技术值得重视的问题     

低压铸造在工程机械泵轮铸件上的应用

介绍了低压铸造工艺的生产流程、工艺设计要点,结合装载机变矩器铸铝件泵轮热节分布分散的结构特点,论述泵轮的低压铸造工艺的设计要点和关键的工艺过程参数温度场、充型速度、充型压力3个方面的控制技术。     

压铸模具结构优选与设计系统开发

介绍了压力铸造成形原理及其工艺过程、剖析了压力铸造成形工艺的优点和存在的缺陷;总结了压力铸造技术的发展历史、应用范围及中国压力铸造生产产品应用领域的多元性,展示了中国压力铸造业发展的广阔前景。     

镁合金真空低压消失模铸造新技术

介绍了一种新的铸造技术--真空低压消失模铸造的工作原理.建立了其在充型过程中的物理模型与数学模型,分析了其铸造工艺的特点及影响因素,以及在铸造高精度、复杂镁合金铸件方面的优势.作为压力铸造、低压铸造的补充,真空低压消失模铸造新技术在铸造高质量和高精度的镁合金铸件中具有广泛的应用前景,另外还可用于铸造高精度、复杂的铝合金铸件.展示了用该新技术铸造成形的复杂的电机壳体、排气管等镁合金铸件.     

浅析棘轮本体金属模低压铸造工艺与模具设计

低压铸造是介于金属型铸造和压力铸造之间的一种铸造方法。其是在一定的压力作用下,将金属熔液注入铸型型腔。并在压力的作用下凝固以获得铸件的方法,本文主要是对棘轮本体金属模低压铸造工艺与模具设计进行探寻和改进,根据以往的各种铸造方法的优势和劣势不断总结经验,不断的探索挖掘,使模具设计及铸造工艺得到了更全面的改进。     

Microstructure and mechanical properties of AM50 alloy according to thickness and forming condition of the products by a high pressure die-casting process

In recent years, Magnesium (Mg) and its alloys have become a center of special interest in the automotive industry. Due to their high specific mechanical properties, they offer a significant weight saving potential in modern vehicle constructions. Most Mg alloys show very good machinability and processability, and even the most complicated die casting parts can be easily produced. The die casting process is a fast production method capable of a high degree of automation for which certain Mg alloys are ideally suited. Although Mg alloys are fulfilling the demands for low specific weight materials with excellent machining and casting abilities, they are still not used in die casting process to the same extent as the competing material aluminum. One of the reasons is that effects of various forming variables for die casting process is not closely examined from the viewpoint of die design. In this study, step die and flowability tests for AM50 were performed by die casting process according to various combination of casting pressure and plunger velocity. Microstructure, Vickers hardness and tensile tests were examined and performed for each specimen to verify effects of forming conditions.     

快速成型技术在熔模精密铸造中的应用

快速成型技术是具有高柔性的先进制造技术,无需任何专用工具,由零件的CAD模型直接完成零件或零件原型的成型制造。将快速成型技术与铸造技术结合起来,采用快速成型技术制造铸型或铸模,可极大提高铸造的柔性和生产效率,满足新品试制和小批量生产的需求,这也是快速成型技术的一个主要发展方向。本文通过几种快速成型模在熔模精密铸造中的实际应用和试验得出,采用SLA法制作的蜂窝结构快速成型模在尺寸波动方面满足精铸需要,并能实现铸件的快速制造。     

Design and Verification of an Auxiliary System for High Vacuum Die Casting

Vacuum die casting is the optimal method to produce high quality aluminum alloy components.At present,there are still very few systematic studies on vacuum die casting theory and equipment design.On the basis of the existing theories of the vacuum die casting pumping and venting systems,a simplified model is established in this research.The model has an aggregate unit consisted of "vacuum pump + buffer tank" and a cylindrical container(including the shot sleeve,cavity and exhaust channel).The theoretical analysis is carried out between the cavity pressure and the pumping time under different volume models.An auxiliary system for high vacuum die casting is designed based on the above analysis.This system is composed of a vacuum control machine and a new vacuum stop valve.The machine has a human-computer control mode with "programmable logic controller(PLC) + touch screen" and a real-time monitoring function of vacuum degree for buffer tank and die cavity.The vacuum stop valve with the "compressed gas + piston rod + labyrinth groove" structure can realize the function of whole-process vacuum venting.The new system shows great advantages on vacuuming the cavity with a much faster speed by making tests on an existing die casting mold and a 250 t die casting machine.A die cavity pressure less than 10 kPa can be reached within 0.8 s in the experiment and the porosity of castings can be greatly decreased.The systematic studies on vacuum die casting theory and equipment have a great guiding significance for high vacuum die casting,and can also be applied to other high vacuum forming in related theoretical and practical research.     

真空压铸设备升级改造研究与实践

针对普通真空压铸设备生产过程中出现的产品问题,提出了升级改造压铸机的解决方法并进行实践,为压铸产品质量改善提供一种途径。通过设计并比较不同的方案,经过多次实践实验,确定了升级改造用真空箱结构,并对相应的模具结构设计提出了经济可行的方法,经过试模验证了模具设计的合理性,产品质量更好,实现了有效可靠的压铸机控制系统,为压铸行业设备升级改造提供经济性和可靠性均较高的解决方案。     

Novel technologies for the lost foam casting process

Lost foam casting (LFC) is a green precision casting process categorized as a near net forming technology. Yet, despite its popularity, it still suffers from some technological problems, such as poor filling ability of the castings, coarse and non-dense microstructure, low mechanical properties for the Al and Mg LFC processes, and defective carburization for the low carbon steel LFC process. These drawbacks restrict the development and widespread application of the LFC process. To solve these problems, the present study developed several novel LFC technologies, namely, LFC technologies under vacuum and low pressure, vibration solidification, and pressure solidification conditions; expendable shell casting technology; and preparation technology of bimetallic castings based on the LFC process. The results showed that the LFC under vacuum and low pressure evidently improved the filling ability and solved the oxidization problem of the alloys, which is suitable for producing complex and thinwall castings. The vibration and pressure solidifications increased the compactness of the castings and refined the microstructure, significantly improving the mechanical properties of the castings. The expendable shell casting technology could solve the pore, carburization, and inclusion defects of the traditional LFC method, obtaining castings with acceptable surface quality. Moreover, the Al/Mg and Al/Al bimetallic castings with acceptable metallurgical bonding were successfully fabricated using the LFC process. These proposed novel LFC technologies can solve the current technological issues and promote the technological progress of the LFC process.     

激光熔覆直接成形金属铸造模具的探讨

探讨激光熔覆金属粉末快速原型技术直接制造铸造用金属模具的问题。文章介绍了这种技术的特点：快速直接制造金属原型，其制件的结构、形状和功能特性都能符合最终用途，可大大缩短产品的开发周期。通过分析砂型金属模具、金属型、压铸型、石蜡模母模和消失模母模等铸造模具的结构特征和在制造上的要求，说明了激光熔覆金属粉末快速原型技术适用于这些铸造模具的制造；指出了在应用中需要进一步轻量化、低耗化，并分别提出了可行的对策。随着各种相关技术的发展及其综台、集成度的提高，激光熔覆金属粉末制造铸造模具的轻量化、低耗化将逐步实现，其应用将更广泛。