共查询到18条相似文献,搜索用时 109 毫秒
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消失模铸造工艺金属液充型过程比普通砂型铸造复杂的多,同时存在多种物理、化学反应,并直接影响铸件的内在质量,以生产制动盘为例,结合消失模铸造的工艺过程,分析夹渣、夹砂等夹杂类缺陷产生的原因和防止方法。 相似文献
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重点对铝合金发动机缸体的压铸成形和铝合金水冷双层排气管的消失模铸造成形工艺过程中的关键核心技术、铸造的质量问题及其处理措施等进行了简要介绍,希望对读者有借鉴作用。 相似文献
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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。 相似文献
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《机械工程与自动化》2020,(2)
拉伸试棒广泛应用于新材料、新工艺的开发,而标准拉伸试棒铸造模具体积大,造成材料的浪费;型腔截面变化复杂,充型过程中会产生飞溅,在铝合金铸造时容易产生冷隔、浇不足和缩松等缺陷。针对这一情况,设计了一种体积小、截面简单的模具,并用Fluent软件对A357铝合金重力铸造工艺进行了模拟,研究温度场和流场的变化规律,实现充型过程热流耦合和凝固过程的温度场计算,并预测铸件质量。研究结果表明,新模具充型良好,速度平稳,凝固时试棒位置能够有效补缩,消除了缩松缺陷。 相似文献
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针对消失模铸造模样制造过程中的发泡珠粒射料充填问题,建立数学模型描述珠粒射料充填过程中的气固两相流动过程并进行了数值模拟,采用双流体模型描述气体相和颗粒相,SIMPLE方法求解气固两相的连续方程和动量方程。为验证模拟结果,采用自行设计的模具进行珠粒射料充填,并用数码摄像机记录了整个射料过程。数值模拟和试验结果显示:在射料充填前期,模具底部空气流动速度快,携带能力强,到达模具底部的珠粒都被带到顶部堆积。珠粒充填超过2/3以后,珠粒才开始在底部堆积,最后形成一个椭圆形漩涡并逐步消失。数值模拟和试验结果符合较好。 相似文献
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A new shell casting process based on expendable pattern with vacuum and low-pressure casting for aluminum and magnesium alloys 总被引:1,自引:1,他引:0
Wenming Jiang Zitian Fan Defeng Liao Xuanpu Dong Zhong Zhao 《The International Journal of Advanced Manufacturing Technology》2010,51(1-4):25-34
A new shell casting process, with the adoption of the foam pattern of lost foam casting (LFC) as prototype and the combination of the thin shell fabrication technology of investment casting and vacuum and low-pressure casting process, was proposed for manufacturing complicated and thin-walled aluminum and magnesium alloy precision castings. Loose-sand uniting vacuum was used in the new process to further reinforce the thin shell, and the new process proves to be a process with simple process, low cost, and high thin shell strength. Because the molten metal filling and solidification are completed under air pressure and vacuum level, the filling capability and feeding capacity of the molten metal are greatly improved, and the castings become denser. This paper mainly investigated the fabrication technology of thin shell based on foam pattern prototype, the removing foam and roasting shell process and vacuum and low-pressure casting process. The few-layer compound thin shell of silica sol–sodium silicate was adopted for the new process. Removing foam pattern was carried out at 250°C for 30 min, and the shell was roasted at 800°C for 1 h. Combined with the vacuum and low-pressure casting process, this new shell casting process has successfully produced thin wall and complex aluminum and magnesium alloy parts with high quality. In addition, comparisons in terms of filling ability, microstructure, mechanical properties, porosity, and surface roughness among this new shell casting, gravity casting, and LFC were also made to show the characterization of this new shell casting process. 相似文献
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铸造过程的多尺度模拟研究进展 总被引:9,自引:0,他引:9
铸造行业对国民经济的发展具有重要作用,但我国与国外有很大差距,严重制约着经济的发展。铸造成形加工技术的发展趋势之一是用计算机模拟仿真技术来逐步代替传统的经验性研究方法。计算机模拟技术已成为改造传统铸造产业的必由之路,在生产中得到了越来越广泛的应用。随着铸造过程宏观模拟技术的成熟,研究者们把目光转向了微观过程模拟与多尺度模拟。主要针对目前的研究热点和发展趋势作了阐述,特别是对新一代精确铸造充型凝固过程模拟、铸造过程的应力应变分析、微观组织的形成与演变及并行工程环境下的多尺度模拟仿真等方面的国内外最新进展进行了分析,同时重点介绍了我国在这方面的研究成果。 相似文献
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Wenming Jiang Zitian Fan Dejun Liu Hebao Wu 《The International Journal of Advanced Manufacturing Technology》2013,67(9-12):2459-2468
In this study, a new casing process named expendable pattern shell casting process with vacuum and low pressure (EPSC-VL) was introduced to produce complicated and thin-walled aluminum alloy castings. The gas flowrate is one of the most important process parameters for manufacturing castings during the EPSC-VL process. In the present work, the influence of gas flowrate on the filling ability and internal quality of A356 aluminum alloy castings fabricated by the EPSC-VL process were investigated. Moreover, the filling ability, internal quality, as well as mechanical properties of A356 aluminum alloy castings obtained by EPSC-VL and lost foam casting (LFC) processes were also compared. The results obtained suggested that the filling length increased with the increase of gas flowrate, and the filling length of the thick section was larger than that of the thin section under the same gas flowrate when the gas flowrate was less than 19 m3/h. Furthermore, the porosity of castings decreased with increasing gas flowrate, and the microstructure of castings became denser, and the internal quality of castings was obviously improved. The comparison experiments showed that the EPSC-VL process had superior filling ability, internal quality, and mechanical properties compared with the LFC process, and the surface quality of castings obtained by EPSC-VL process was also better than that of the LFC process. The casting practice of complicated and thin-walled A356 aluminum alloy intake manifold part also suggested that the EPSC-VL process had an obvious advantage for the fabrication of complicated and thin-walled aluminum alloy castings compared with the LFC process. 相似文献
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介绍了消失模铸造泡沫模样的成形过程.采用可编程控制器为主要控制元件,研制出一台泡沫模样成形控制装置,并对控制系统的硬件和软件构成、控制方式及特点作了详细介绍.最后利用该控制装置制作出表面光洁的优质泡沫模样. 相似文献
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从消失模的铸件设计原则、铸造工艺设计原则和浸渗技术三个方面进行分析,进而对消失模铸造有了深入的认识,并提出消失模铸造工艺技术的一些规范和要求,避免工艺技术因素引起的铸造缺陷和废品。 相似文献
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针对目前消失模模样加工发展的要求,研究了EPS快速成型技术,采用CAD/CAM技术、计算机控制技术、数控技术等知识,开发了一种EPS快速成型系统.该系统通过成型软件自动生成加工路径,将其转化成步进电机的输入信号,从而控制机械部分的运动,以电热丝气化EPS的切割方式,切割出一个完整的三维模型.此系统总体分为三大块:机械部... 相似文献