基于数值模拟的轮毂铸件铸造工艺设计

对水轮发电机轮毂铸件的铸造工艺进行了设计,通过对铸件充型过程中的流场、凝固过程的温度场进行数值模拟,得出铸件在浇注时充型平稳,无缩孔、缩松等缺陷的产生,验证了工艺的可行性。     

铸铁件铸造缺陷的有限元分析

采用有限元法建立了铸件凝固过程的数学模型，考虑材料随温度变化的非线性因素和相变中结晶潜热问题，对铸造凝固过程进行了数值模拟，得到了铸件在凝固过程的瞬态温度场、温度梯度场的分布和变化规律。预测出了铸件可能出现缩孔、缩松等铸造缺陷的位置，结果表明模拟预测与生产验证结果基本一致。     

微车制动产品铝合金重力铸造缺陷分析及改进

采用铸造专用软件Pro Cast2004对现有铝合金铸件铸造工艺进行充型过程、凝固过程和疏松、缩孔位置等方面的分析,同时结合实际工艺试验的结果分析,模拟预测出可能产生的缺陷(气孔、缩孔和缩松),从而判断浇注系统的浇冒口设置、浇铸工艺和操作程序等的合理性,并通过工艺验证进行验证,从而提供现有铸造模具和工艺对产品品质影响的关系,并制定了改进措施。     

镁合金轮毂低压铸造工艺数值模拟

对汽车上镁合金轮毂的低压铸造过程进行了数值模拟，研究了填充和凝固过程中温度场与流场的分布，预测在此过程中可能出现的各种缺陷，结果发现，通过降低浇注速度，可有效地消除在浇铸过程中所产生的气孔和部分缩孔缺陷。对于容易在轮辋与轮辐连接处产生的热节，通过对这些部位的模具冷却性能进行研究，分析了不同冷却方式对热节产生的影响，结果发现，单独设置侧模冷却管道是一种有效的冷却方式，可以使热节减小，并使其位置发生改变。     

大型球磨机端盖铸造工艺模拟及优化

利用三维绘图软件生成球磨机端盖铸件实体模型,运用华铸软件对球磨机端盖铸造工艺进行温度场的数值模拟,预测缩孔、缩松等缺陷产生的部位,并分析形成原因。根据模拟结果对冒口、冷铁尺寸进行改进,优化工艺。改进的工艺实现了顺序凝固,消除了缩孔、缩松缺陷,保证了铸件质量。     

铝合金活塞铸造工艺数值模拟研究

针对铝合金活塞铸造成型过程中存在缩松、缩孔、晶粒尺寸不均匀等缺陷问题,利用Procast专业铸造有限元分析软件,进行了ZL108铝合金活塞铸造工艺的数值模拟研究,利用正交试验法考察了浇注温度、浇注速度、模具温度3个工艺参数,对数值模拟结果进行了晶粒尺寸、缩松缩孔分布、充型率等几个方面的综合评分.研究结果表明:最优的工艺参数组合为700℃的浇注温度、0.3 kg/s的浇注速度和150℃的模具温度.ZL108铝合金活塞铸造工艺数值模拟研究结果为壁厚不均匀的重要复杂零件铸造成型提供了理论指导,节省零件工艺优化设计的成本和时间.     

ZL101A机构箱铸件缩孔缩松缺陷数值模拟分析

针对传统砂型重力铸造制备ZL101A铝合金机构箱铸件普遍存在的缩孔缩松等缺陷,运用华铸CAE软件对该铸件的凝固过程进行了模拟,对初始铸造工艺进行了优化。结果表明:经过液相分布→缩孔形成→Niyama缩松分析后,精确预测了缩孔缩松缺陷产生部位;优化后铸造工艺制备的ZL101A机构箱铸件缩孔缩松较少,且分布较合理。     

铸钢件缩孔及缩松缺陷的消除

通过分析铸钢件缩孔及缩松产生的机理，总结出铸件产生缩孔及缩松缺陷的部位，提出从改进浇注系统、改变铸件结构、适当提高浇注温度及控制浇注速度等几个方面消除铸件中的缩孔及缩松。     

大型导叶铸件铸造缺陷分析及工艺优化

本文利用数值模拟技术分析了导叶铸件容易出现缩孔、缩松缺陷的位置。针对导叶铸件容易出现铸造缺陷的位置建立了导叶铸件合理的温度场，并设计出了环形本体补贴，形成了顺序凝固时所需要的温度梯度场，解决了导叶铸件长轴和瓣体上缩孔、缩松等缺陷的问题。     

基于CASTSoft_CAE软件的铸件缺陷预测

以金属凝固理论为基础,I-DEAS和CASTSoft_CAE软件为平台,建立法兰盘凝固过程的三维模型。对法兰盘凝固过程的温度场和凝固过程进行数值模拟,温度最大值出现在法兰盘中心部位,最小值出现在法兰盘边缘。应用新山判据预测铸件可能出现缩孔、缩松等铸造缺陷的位置,发现在法兰盘中心处出现缺陷。     

Effect of process parameters on impact strength of Al-7% Si alloy castings produced by VAEPC process

The castings produced by the evaporative pattern casting (EPC) process have blow holes. The blow holes in EPC castings are because of the non-escape of the gas produced as a result of burning of polystyrene pattern in the sand mold. To overcome the problem of blow holes, the EPC process is combined with the vacuum (V)- process. The vacuum applied to EPC mold draws the decomposed gases and improves the casting quality produced by the EPC process. The developed hybrid process has been termed as the vacuum assisted evaporative pattern casting (VAEPC) process. The objective of this paper to investigates the effect of process parameters, i.e, degree of vacuum, pouring temperature, grainfineness number, amplitude of vibration and time of vibration on the impact strength of Al-7% Si alloy castings in VAEPC process. In order to evaluate the effect of selected process parameters, the response surface methodology (RSM) is used to formulate a mathematical model which correlates the independent process parameters with the desired impact strength. The central composite rotatable design has been used to conduct the experiments. The results indicate that the impact strength decreases with increases in the grainfineness number and pouring temperature. Whereas, it has an inverse relationship with amplitude of vibration, time of vibration and degree of vacuum. The best value of impact strength (2.34 N/mm²) has been obtained at 400 mm Hg degree of vacuum imposed, 650°C as pouring temperature, 60 as sand grainfineness number, 460 μm as amplitude of vibration, and 70 s as time of vibration.     

汽车缸套离心铸造凝固数值模拟研究

建立汽车缸套离心铸造凝固过程的数学及物理模型,对汽车缸套离心铸造的凝固过程进行数值模拟,得到汽车缸套离心铸造过程中的温度场、液固相分布及缩孔缩松状况。结果表明:采用数值模拟分析能够使汽车缸套的高速、高温、复杂的卧式离心铸造过程可视化,并可方便地通过改变铸造参数来分析对铸造效果的影响;合适的铸型转速会对充型产生较大的影响,过小则会产生雨淋现象,过大则会使充型不连续;为减少铸件外表面及端面与内表面中心部分凝固速度的差距,可以适当提高铸型的预热温度。     

STUDY ON NUMERICAL SIMULATION OF MOLD-FILLING AND SOLIDIFICATION PROCESSES OF SHAPED CASTING

０ＩＮＴＲＯＤＵＣＴＩＯＮＩｎｒｅｃｅｎｔｙｅａｒｓ,ｃｏｎｓｉｄｅｒａｂｌｅｄｅｖｅｌｏｐｍｅｎｔｓｈａｖｅｔａｋｅｎｐｌａｃｅｉｎｔｈｅｆｉｅｌｄｏｆＣＡＤａｎｄｓｏｌｉｄｉｆｉｃａｔｉｏｎｍｏｄｅｌｉｎｇｏｆｃａｓｔｉｎｇｐｒｏｃｅｓｓ［１～...     

Optimization of high-pressure die-casting process parameters using artificial neural network

High-pressure die casting is a versatile process for producing engineered metal parts. There are many attributes involved which contribute to the complexity of the process. It is essential for the engineers to optimize the process parameters and improve the surface quality. However, the process parameters are interdependent and in conflict in a complicated way, and optimization of the combination of processes is time-consuming. In this work, an evaluation system for the surface defect of casting has been established to quantify surface defects, and artificial neural network was introduced to generalize the correlation between surface defects and die-casting parameters, such as mold temperature, pouring temperature, and injection velocity. It was found that the trained network has great forecast ability. Furthermore, the trained neural network was employed as an objective function to optimize the processes. The optimal parameters were employed, and the castings with acceptable surface quality were achieved.     

Plaster casting process for prototyping of die casting based on rapid tooling

Rapid prototyping (RP) combined with a gravity casting process can provide a suitable substitute with steel tool die casting for prototyping metal casting. Due to differences between die casting and gravity casting, there are several drawbacks in RP simulated die casting. This paper is concerned with the development of a new plaster die casting process that combines pressurization and vibration for prototyping of die castings, and with a plaster die casting machine that has a structure similar to that of a die casting machine. The machine utilizes an oil cylinder for pressurization and a magnetic actuator for vibration. A rapid prototyped pattern is made by the laminated object manufacturing (LOM) process to prepare a plaster mold. In the process, a plunger in the developed machine simultaneously pressurizes and vibrates the molten metal to fill the plaster mold completely and to facilitate the creation of nuclei in the molten metal, respectively. The developed machine has produced a prototype of an end clutch cover with remarkable improvement in mechanical properties.     

金属型铝合金重力浇注装置及其模具设计的研究

为适应较小规模铸造企业的生产模式、有效提高铸件质苎．对铝合金重力浇注装置及其模具结构进行设计研究。在装置上采用简单的机械结构使之方便手动操作，使用完全金属型模具并使之具有倾转功能。研究发现在浇注过程中具有操作简单方便、易于维护，并且制造成本低廉、模具设计制造周期短的特点。铝合金液体在模具中的充型和排气效果良好，可减少气孔、缩孔等铸造缺陷。特别适用与中小型企业的小批量铸件的生产和产品零件的试制加工。     

Design optimization of clutch housing mold by fluid flow and solidification simulation

Aluminum die casting is so complex where flow momentum is critical matter in the mould filling process due the high velocity of the liquid metal. Actually, in complex parts the exact calculation of mould filling performance with using experimental knowledge is almost impossible. Aluminum die castings play a definitive role in the manufacturing of lightweight automobile bodies. Hence it is more essential today that these castings be produced with the high quality methods. In this condition the simulation is becoming more important in the designing procedure. This saves time and reduces the cost of the casting system design, which is an advantage of using simulation programs. Also, economical utilization of materials can be obtained when the quantity of test castings is decreased. This paper describes the advantages of the clutch housing die casting mold simulations to achieve better casting system design in High pressure die castings (HPDC). Filling analysis is used to determine the size and location of the gate as well as proper runner system design for ensuring a complete and balanced filling of the clutch housing part.

     

Plaster casting process for prototyping of die casting based on rapid tooling

Rapid prototyping (RP) combined with a gravity casting process can provide a suitable substitute with steel tool die casting for prototyping metal casting. Due to differences between die casting and gravity casting, there are several drawbacks in RP simulated die casting. This paper is concerned with the development of a new plaster die casting process that combines pressurization and vibration for prototyping of die castings, and with a plaster die casting machine that has a structure similar to that of a die casting machine. The machine utilizes an oil cylinder for pressurization and a magnetic actuator for vibration. A rapid prototyped pattern is made by the laminated object manufacturing (LOM) process to prepare a plaster mold. In the process, a plunger in the developed machine simultaneously pressurizes and vibrates the molten metal to fill the plaster mold completely and to facilitate the creation of nuclei in the molten metal, respectively. The developed machine has produced a prototype of an end clutch cover with remarkable improvement in mechanical properties.     

Application of implicit surface in post-processing of casting simulation

With the development of casting process and its numerical simulation technique, many demands of realism and clearness in post-processing have arisen. This paper introduces the implicit surface to post-processing for the results of casting simulation so as to meet these demands. In this paper, a robust and fully automatic algorithm is proposed for extracting the implicit surface in the signed distance function calculated from the import stereolithography files. Then several applications of implicit surface in the post-processing of casting simulation are listed in two categories. The applications in the first category include fast rendering of massive data, section view in arbitrary direction, visualization of residual liquid, and casting deformation, giving clear and pretty visualization of the results in simulation, and making it possible for engineers and process designers to look through the opaque mold, gain insights to casting process, and locate possible defects. The applications in the second category involve thickness distribution and modulus calculation, which offer important characteristics of castings and facilitate the optimization of casting processes.     

消失模铸造充型与凝固过程的计算机仿真

根据消失模铸造液态金属充型及液态金属—模样界面的推进机制,提出了充型过程界面推移位置的人工神经网络算法。根据计算得出的界面位置,用SOLA算法计算了充型过程中液态金属的流场,并耦合计算了充型过程中的温度场。根据计算得到的充型结束时铸件及铸型温度场,求解三维导热微分方程,计算了铸件凝固过程的温度场。结合消失模铸造型壁移动的规律,预测了球墨铸铁件消失模铸造的收缩缺陷。计算模拟结果与充型过程实际测试结果及铸件解剖结果一致。