制动器安装底板低压铸造浇注系统设计及工艺参数优化

根据制动器安装底板的形状和结构特点,低压铸造浇注系统采用侧浇口形式的封闭式浇注系统。利用数值模拟技术和田口方法,对制动器安装底板低压铸造工艺参数进行优化,以铸件的孔隙率最小为优化目标,研究了浇注温度、模具预热温度以及保压压力这3个工艺参数对铸件孔隙率大小的影响。利用均值分析和方差分析对数值模拟的试验结果进行分析可知,对铸件孔隙率大小影响最大且最显著的是浇注温度,其次是模具预热温度,最后是保压压力。通过田口方法获得的最优参数组合为:浇注温度720℃、模具预热温度300℃、保压压力250 kPa。     

7001高强铝合金挤压铸造过程的数值模拟分析

针对轻量化铝合金零件力学性能、质量和精度要求高等问题,建立了铝合金挤压铸造有限元分析模型。对挤压模具在实际工况下的力学性能进行了分析,对其结构进行了优化,分析了不同浇注温度、模具温度、挤压速度及挤压力对铝合金挤压铸造缩松缩孔特性的影响。结果表明,设计的挤压铸造模具满足强度和变形要求,铝合金最佳挤压铸造工艺参数为浇注温度650℃,模具温度200℃,挤压速度0.01m/s,挤压压力50 MPa;优化的模具结构其力学性能及铸造特性更优良。     

A319合金挤压铸造凝固过程数值研究

利用ANSYS有限元分析软件,考虑相变潜热、对流边界条件和界面传热系数等因素,建立了铝合金挤压铸造凝固过程温度场模型,研究了挤压铸造过程参数(挤压力及模具预热温度)对铸件凝固过程温度分布的影响.通过分析不同挤压力下铸件的显微组织,表明模拟结果与实验结果基本一致.     

挤压铸造代替压铸制造铝合金壳体的工艺改进

针对压铸铝合金壳体件存在气孔等铸造缺陷,分析了其产生的原因,并用间接挤压铸造工艺取代压铸工艺。采用的间接挤压铸造工艺参数:充型速度为0.03～0.05m/s,充型时间为0.2s,模具温度为250～300℃,浇注温度为720～740℃,加压压力为150MPa。工艺改进后,成功地制造出了耐1.5MPa气密性要求的产品,其力学性能高于压铸产品,且内部无铸造缺陷。     

挤压铸造摩托车制动蹄块的研制

通过对南方125摩托车制动蹄块采用挤压铸造取代压力铸造的研制,阐述两种铸造工艺的本质区别;着重介绍对向式间接挤压铸造一模多铸的工艺过程、模具结构、工艺参数以及铸件组织与性能对比;试分析其充填理论。说明:挤压铸造部分取代压铸有良好的应用前景。     

舵面的间接正向挤压铸造成形技术研究

指出了舵面间接正向挤压铸造工艺特点，分析了压力的变化和液流的充填性对舵面成形性的影响。其研究成果丰富了挤压铸造理论和工艺的应用范围，具有较大的实用意义。     

挤压铸造舵面的成型规律与参数

研究了舵面的间接正挤压铸造工艺 ;分析了成型时的金属液流动规律 ,探讨了各压力阶段对成型性能的影响 ,给定了合理的挤压铸造工艺参数     

挤压铸造件力学性能影响因素及交互作用研究

为优化挤压铸造工艺参数,改善铸件的力学性能,选取浇注温度、挤压压力和保压时间作为优化变量,抗拉强度、硬度和伸长率作为响应性能指标,采用响应曲面分析法,建立相对应的预测回归模型并进行方差分析,得出各参数及其交互作用对力学性能的影响。利用Design-Expert软件优化后得到了各工艺参数间的最优组合:浇注温度为750℃,挤压压力为150MPa,保压时间为21.37s。     

挤压铸造舵面的成型规律与参数

研究了舵面的间接正挤压铸造工艺;分析了成型时的金属液流动规律,探讨了各压力阶段对成型性能的影响,给定了合理的挤压铸造工艺参数。     

汽车用AZ80合金的挤压铸造工艺及组织性能研究

对汽车用AZ80合金进行挤压铸造,研究浇注温度、挤压压力、模具预热温度和保压时间对AZ80合金组织和力学性能的影响,并分析其作用机理。结果表明,AZ80合金的适宜挤压铸造工艺为:浇注温度700℃、挤压压力90MPa、模具预热温度为250℃、保压时间为25 s,在此工艺下的AZ80合金可以取得较好的强度和塑性结合;AZ80合金力学性能的提高,主要与挤压工艺参数调控合金晶粒大小和显微缺陷有关。     

Continuous squeeze casting process by mass production

S queeze casting has been widely used for automotive struc tural parts because it offers a vast material selection from aluminum and magnesium alloys. In comparison with low pressure die casting, squeeze casting also overcomes many fluidity problems and thus it can use both hypereutectic and hypoeutectic alloys such as 319, 383 and 390. Squeeze casting can also apply “spot solidification” technology in addition to directional solidification method. The shortcoming of directional solidificati…     

THERMOMECHANICAL MODELING OF SOLIDIFICATION PROCESS OF SQUEEZE CASTING I. Mathematic Model and Solution Methodology

开发了模拟挤压铸造凝固过程中铸件温度、应力及形状变化的有限元模型. 该模型包括了凝固过程中潜热的释放和体积收缩效应、界面传热和变形的相互作用以及凝固壳在冲头压力下的变形等. 应力场模拟中采用热弹粘塑性本构模型描述凝固壳的变形, 并对液相和糊状区进行了特殊处理. 利用接触算法处理铸件与模具界面, 并且采用一种特殊的迭代法来模拟冲头的运动. 该模型可以用来研究模具设计和工艺参数(如模具温度及冲头压力等)对铸件质量的影响.     

Optimization of squeeze cast parameters of LM6 aluminium alloy for surface roughness using Taguchi method

The ability to produce near net shape components with good surface finish is made possible by means of squeeze casting, a hybrid metal forming process combining features of both casting and forging in a single operation. The primary objective of this paper is to analyze the influence of the process parameters on surface roughness in squeeze casting of LM6 aluminium alloy using Taguchi method. In Taguchi method, a three level orthogonal array has been used to determine the S/N ratio. Analysis of variance and the ‘F’-test values are used to determine the most significant process parameters affecting the surface roughness. The results indicated that the squeeze pressure and the die preheating temperature are the recognized parameters to cause appreciable improvement in the surface finish of the squeeze cast components.     

基于正交试验的液态模锻Al-Sn-Cu轴套中Sn的宏观偏析

采用正交试验法分析了液态模锻Al-Sn-Cu轴套中Sn的宏观偏析规律。结果表明:液态模锻Al-Sn-Cu轴套不可避免的产生Sn的宏观偏析,铸件中同时存在着正偏析和逆偏析,正偏析出现在浇铸中心的近端,逆偏析主要存在于浇铸中心的远端;铸件凝固后期,低熔点液相被强制挤压至热节位置,形成粗晶区和细晶区相间的双峰组织,细晶区Sn的质量分数明显较高。液态模锻工艺参数对铸件宏观偏析产生较大影响,对Sn偏析影响由大到小依次是浇注温度、模具温度、保压时间及比压;本次实验条件下,当浇注温度为700℃,模具温度为240℃,比压为80 MPa,保压时间为5 s时,轴套铸件中Sn元素分布较均匀,Sn元素的宏观偏析得到减轻。     

间接挤压铸造模具设计特点及研究

结合间接挤压铸造工艺的特点,给出了间接挤压铸造模具设计流程和模具结构设计中基本思想方法及要点,对 某些重要的设计程序进行了详细论述。     

铝合金超低速压铸工艺参数对铸件性能的影响

应用具有不同浇道尺寸的简单圆形拉伸试样研究压铸工艺参数对ADC12铝合金超低速压铸件性能的影响,以优化超低速压铸工艺及其参数。试验结果表明,各种超低速压铸工艺条件下铸件的密度都比普通压铸高,影响铸件性能的主要因素不再是气孔,而是合金的凝固组织及飞溅凝固片和氧化夹杂等缺陷。在超低速实验条件下,浇道截面尺寸越大,对铸件性能影响越大,不同浇道尺寸对应有最佳浇道速度,在试验的三种浇道条件下,最佳浇道速度均低于0.6m/s;模具预热温度、浇注温度、铸造压力都有最佳值;在无增压条件下,仅采用较大的压射压力也可使铸件获得较好的力学性能。     

The influence of pressure during solidification of high pressure die cast aluminium telecommunications components

The effects of process variables on the quality of high-pressure die cast components was determined with the aid of in-cavity pressure sensors. In particular, the effects of set intensification pressure, delay time, and casting velocity have been investigated. The in-cavity pressure sensor has been used to determine how conditions within the die-cavity are related to the process parameters regulated by the die casting machine, and in turn the effect of variations in these parameters on the integrity of the final part. Porosity was found to decrease with increasing intensification pressure and increase with increasing casting velocity. The delay time before the application of the intensification pressure was not observed to have a significant effect on porosity levels.     

Mechanical and Microstructural Evaluation of Squeeze Cast Al-4%Cu Alloy Using a Full-Factorial Experimental Design

A full factorial design was employed to investigate the effect of squeeze pressure in conjunction with thermal parameters, i.e., melt and die temperatures, on the mechanical properties of a squeeze cast Al-4%Cu alloy. Considerable variations in mechanical properties existed between different test runs, and these were discussed based on cooling rates previously quantified for a squeeze-cast Al-4%Cu alloy. The completeness of a full factorial design not only identified a combination of process parameters for optimum results but also facilitated an evaluation of the minimum pressure required to eliminate porosity and influence the die temperature on the microstructure of the squeeze-cast alloy. In addition to the optimum run, particular importance was given to those runs that had more desirable levels of control factors with respect to energy consumption or tooling life. A microstructural analysis of these runs indicated the possibility of precipitation hardening that can open up further investigations toward the opportunities associated with in situ heat treatment of age-hardening, squeeze cast aluminum alloys.     

冲头式挤压铸造工艺参数对ZA27合金力学性能的影响

采用正交试验分析了冲头式挤压铸造工艺参数对ＺＡ２７合金力学性能指标的影响。结果表明：ＺＡ２７合金冲头式挤压铸造工艺参数影响的主次顺序为比压、铸型温度、浇注温度和保压时间。在适宜的工艺参数下ＺＡ２７合金力学性能可以达到：σｂ＝４４０ＭＰａ,δ５＝１２％,ＨＢＳ１３０     

The effect of die casting machine parameters on porosity of aluminium die castings

The primary objective of this research is to investigate the effect of machine related parameters on porosity formation in the aluminum die casting process. The amount and distribution of porosity in die castings was examined in relation to plunger velocity during the 1st phase, fast shot set point, plunger velocity during the 2nd phase, die cavity filling time and multiplied pressure during the 3rd phase.

Standard statistical analysis was performed in order to identify the effect of each of the considered parameters and parameter interactions on porosity formation. It was found that, among the parameters considered, multiplied pressure, plunger velocity in the 2nd phase and die cavity filling time have the most significant effect on porosity formation. Using optimal die casting machine parameter levels, the optimum porosity value of aluminum alloy die-castings was predicted. The results were confirmed by further experiments.