汽车仪表座因其壁薄、结构复杂,在注塑过程中易出现熔接痕,影响了塑件的表观质量及力学性能.借助计算机辅助分析软件Autodesk Moldflow Insight 2010(AMI 2010)及正交试验法,并采用方差分析方法优化工艺参数,获得了最优工艺参数组合,改善了熔接痕缺陷,缩短了注塑周期,提高了生产效率.实践表明,CAE技术能对实际生产有一定指导意义.

Through the research on low-pressure casting, combined with structure of aluminum alloy, this paper introduces the typical system design of low pressure casting process, including the designs of feeding system and exhaust system. The control techniques of the process parameters which include filling pressure, filling speed and temperature field are studied in the paper to ensure the stability of the quality of the products.

针对铝合金盘类零件在压铸生产中存在针孔、冷斑、流痕和大平面变形等问题,在分析其压铸工艺的基础上,对压铸模具进行了设计.根据结构特点,采用了多杆均布、扁平连接槽的设计,并采用较大面积和较宽的内浇口,实行慢浇和快速高压并保压的工艺.生产实践表明,改进后的方案能有效地减少铸造缺陷,提高了产品的合格率.

铝硅合金广泛应用于飞机、内燃机、汽车等重要零部件,为获得越来越高的力学性能要求,合理的设计铝硅合金的熔炼工艺、处理工艺及浇注工艺极为重要.结合实际应用介绍了铝硅合金铸件的熔炼工艺、精炼变质处理工艺及熔渣直接提铝工艺等,在一定程度上节约了成本、保证了产品质量,并对保护环境有明显的效果.

为了提高不锈钢桨叶的表面耐磨蚀性能,采用激光合金化技术在1Cr18Ni9Ti不锈钢表面制备了Mn-Al2O3和Mn-Al2O3-NiWC合金化层,原位获得均由枝晶、共晶和未熔氧化铝颗粒组成的高锰钢基复合耐磨蚀涂层,并通过正交试验研究了两种合金化层的显微组织和耐磨蚀性能.结果表明,所有的正交参量下激光合金化Mn-Al2O3均可提高不锈钢的耐磨性,但耐蚀性有的提高,有的降低;参量因素对合金化层耐磨性的影响顺序为Al2O3添加量、扫描速率、激光功率,对耐蚀性的影响次序则恰恰相反;Al2O3添加量决定了Mn-Al2O3复合涂层中硬质相的含量,从而决定了涂层硬度和耐磨性;两种合金化层表面均发生晶界腐蚀、晶粒内和晶界处的点蚀,其耐蚀性与其多种组织、物相及各自的化学成分和耐蚀性及组织均匀性相关.

为提高汽车变速箱壳体的产品成型质量,对其产品结构进行了分析,设计优化了压铸模具的浇注系统及模具整体结构,并利用计算机仿真技术模拟了压铸充填过程,实现了产品的精密压铸生产.

Recent studies indicated that Mg-(7-11)Zn-4Al (the composition of the alloys in the present paper are given in weight percentage.) based alloys exhibited good creep resistance and additions of trace alkaline elements to the alloys further improved the mechanical properties at elevated temperatures. In order to optimize the zinc concentration and reveal the effect of small amount of alkaline element additions to Mg-Zn-Al ternary alloys on their microstructure and elevated temperature creep resistance, five alloys with compositions of Mg-7Zn-4Al, Mg-9Zn-4Al, Mg-11Zn-4Al, Mg-11Zn-4Al-0.2Ca and Mg-11Zn-4Al-0.6Ca, respectively, were prepared in the present investigation and the microstructure and creep properties of these alloys were studied.

The microstructures of a series of high Zn magnesium alloys Mg-(7-11) Zn-(2-6) Al alloys were clarified, and effects of Zn and Al concentration about the ZA system alloys on the microstructure and properties were also investigated. For Mg-(7-11)Zn-4Al alloys with the Zn content increase, improved creep resistance is obtained due to block τ-Mg32(Al, Zn)49phase, with severe reduction in ultimate strength and ductility, and the best creep property is obtained with 11wt.% Zn concentration. However, a bit increasing Al content of Mg-9Zn-(2-6)Al alloys contributes to the improvement in the ambient and elevated-temperature yield strength, but seriously deteriorates the creep properties for the formation of lamellar φ-Al2Mg5Zn2eutectics or Mg51Zn20phase.

薄壁塑件因其壁厚过小,在其注塑成型过程中易出现熔接痕、短射和翘曲变形等缺陷,翘曲变形是塑件制品的一种严重缺陷,需合理设定相关注塑工艺因素,以保证塑件质量。本文基于MoldFlow软件对一磁疗仪后盖薄壁塑件的注塑成型过程进行有限元模拟,运用正交试验、方差分析法确定最优注塑工艺参数组合。试验表明,利用CAE技术能有效地分析工艺参数对薄壁塑件翘曲变形量的影响规律,对实际生产有一定指导意义。

Super plastic behavior of the commonly as-extruded Mg-3Zn-1Al (ZA31) magnesium alloy is investigated at temperatures ranging from 593 to 623K and strain rates ranging from 8×10-5 to 10-3s-1. The results show that the alloy exhibits excellent super plasticity and the maximum elongation-to-failure reaches 220.4%. The alloy also shows a high strain rate sensitivity exponent of 0.38. Microstructure observations suggest that grain boundary sliding (GBS) with cavity coordination makes a substantial contribution to the super plastic deformation.

Poor surface quality, slag inclusion, porosity and other casting defects easily appear in the aluminum engine cylinder head produced by traditional top-filling casting. To eliminate the problems which were difficult to control, a new bottom pouring method was proposed based on the structural characteristics and technical requirements of engine cylinder head. Gating system was determined for permanent mold casting aluminum alloy engine cylinder head, and cooling method of waterways combined with compressed air was adopted to achieve a sequential solidification of aluminum alloy melt from the bottom to top, which could ensure a smooth filling of molten metal, good exhaust capacity, and also reduce the slag deposition fully. Comparative analysis on casting quality shows that the bottom pouring design is reasonable and feasible, and good surface quality, few casting defects such as porosity, slag hole, and so on, could be realized, significantly improving quality of cylinder head.

The μLSF is a micro-plastic forming method with the laser-induced shock load generated by the plasma in confined medium. It is characterized in the high-pressure and ultra-high strain ratio. This paper developed the model of metal micro-bulk forming by laser shock, simulated the process of forming and compared the influence law of forming depth under the conditions of different laser energy ranging from 3J to 10.6J and sheet thickness ranging from 0.13mm to 0.30mm on. It showed that there exists a threshold for magnitude of the laser energy. The forming depth increased with the increase of magnitude when the magnitude was smaller than the threshold. However, it decreased with the increase of magnitude when the magnitude was larger than the threshold. When the magnitude of the laser energy was chosen, the forming depth presented non-linear reduction with the increase of sheet thickness.

Three design schemes of the runner system of an injection mould for an automobile panel were simulated and optimized based on CAE technology.The optimized gating system helps to increase the quality of product and shorten the development cycle.

注塑CAE常用的数值解法有边界单元法、有限单元法和有限差分法等,但这些解法都需要对所建立的模型进行单元网格划分,网格的好坏、疏密直接关系着CAE分析的效率.因此,网格模型的优化就成为CAE分析的一个关键环节. 一、几何模型的简化 由于软件功能的不同要求,注塑CAE模拟分析的网格模型往往与CAD设计的模型不完全一样,通常为了更为有效地进行模拟分析,在进行CAE的模型构建过程中,往往需要对模具的CAD模型中的一些细节进行简化运算.

Aiming at the flanging process of the cover plates of auto rear wheel,this paser first analyzed the flanging process then pointed out that the substance of its defect is the absolute values of tangentialstrain of flanged edges exceeds the forming limit.With the optimization objective of minimum the the absolute values of tangentialstrain,three parameters,which have great influence on the formability of flanging process,Blank Holder Force,Friction Lubrication Condition and Model Clearance are optimized by Orthogonal design,and then tests are carried out by FEA software Dynaform to obtained the optimized process scheme;lastly,flanging experiment is conducted to verify the optimized process scheme.The results shows that numerical simulation test is reliable and the optimized process scheme can avoid the defects of flanging process.

In order to solve the forming difficulty occurring in the microforming microparts made of hard-to-deform materials, the experimental study on laser-assisted heating of the micropart of aluminum alloy was performed by means of pulsed laser. With the help of ABAQUS finite element software, the coupled thermomechanical finite element model of microupset was built up based on laser-assisted heating method. Then the temperature distribution of the workpiece and microforming process were simulated and analyzed. The results show that the temperature field distributions are oval and flatting with the certain laser parameters (laser power is 800mW,heating time is 0. 08s and spot radius is 0. 1mm) , and that the temperature distribution is uniform after a very short time. The microforming stress using laser-heating method decreased about 30% compared with that of room temperature. The obtained results are helpful to improve the microforming properties of plastic materials and perfect micro- hot and microwarm forming process.

The springback behaviour in microbending is more challenging due to the recovery of the metal and the scale effect shown in microforming. Experiment and numerical simulation are the two important approaches for forming analysis. By applying the static implicit and dynamic explicit codes, the numerical simulation of air bending of V-shape micro-component of brass C1200 was performed. The analysis was carried out using the commercial software ABAQUS. Firstly, the dynamic explicit method was applied in the micro-bending, then the static implicit method was used in unloading to obtain the springback amount. Some important problems in the simulation like the modeling, material model, springback analysis, were explained. The simulation results including the springback were in good agreement with the results of three-point bending experiment for ultra-thin metal sheet. It can be concluded from this investigation that the forming process and springback in microbending is feasible by finite element analysis.

As a new type sheet metal,tailor rolling blanks have forming defects,such as wrinkling,broken and the movement of the transition zone.The defects can be eliminated or reduced and formability can be improved by reasonable control mode of the BHF.The drawing depth,the movement of the transition zone,the strain path etc.of TRB with constant or variational BHF of one-piece holder were studied by the finite-element software ABAQUS.The numerical simulation result indicates that forming depth can be increased by 12.5%,and the movement of the bottom box center and ultimate strain can be reduced by comparing increasing BHF with constant BHF.

Numerical simulation was made on parameters like thickness ratio of sheet metals,its shapes and dimensions,blank holder force and die radius that affect the formation of square box made of tailor rolled blanks.Through orthogonal experiments,the forming depth and movement amounts of transition zone on different conditions were contrasted and analyzed.The strain path of dangerous points was adjusted and an optimized scheme was determined to improve the formability of tailor rolled blanks.

By the numerical simulation and experiments,the process analysis of draw-bending and draw-trimming of the tailor-welded blanks (TWBs) with the thickness ratio 1.2 mm/0.8 mm are made,in which the effect of the blank holder force (BHF), friction factor and die profile radius,etc.on the springback are mainly investigated.The TWBs' springhack angle in the corner of punch and die,the total springhack angle and the sidewall curvature are surveyed in draw-bending and draw-trimming.And the welded line movement,the stress distribution in TWBs forming and their interact relationship are analyzed.The TWBs' springback in draw-bending and draw-trimming are badly influenced by the BHF,friction factor,die profile radius etc.,in which the BHF is the key factor;there is an intimate relationship between TWBs' draw-bending springback/draw-trimming springhack and welded-line movement,by which it will be advantageous to reduce the TWBs' springback through controlling the welded-line movement.In comparison,the TWBs' draw-trimming springhack is smaller than the TWBs' draw-bending springback,so it is better to use draw-trimming process for controlling TWBs' springback and improving the shape precision of TWBs' forming.