共查询到19条相似文献,搜索用时 146 毫秒
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研究了铝合金电磁低压铸造工艺参数关系及控制方法;通过试验及数学分析研究确定了电磁驱动力与电流、流量与电流之间的关系及计算模型,并进行了电磁低压铸造和气压低压铸造实际铸件性能对比。结果表明,电磁低压铸造的流量大小与电极电流成线性关系;并且当电极电流一定时,随出液口高度增加,流量减小,电磁低压铸造生产的铸件性能得到明显提高;电磁低压铸造方法比传统气压低压铸造控制过程更精确。 相似文献
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利用快速成型技术和复合陶瓷型壳技术制备叶轮发泡模具电火花加工电极的精密铸造型壳,实现了电极的快速精密铸造。实践表明,使用该工艺铸造的电极具有尺寸精度高、表面光洁度好的特点,可满足模具电火花加工的使用要求。 相似文献
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钛及钛合金熔模的感应凝壳铸造法 总被引:1,自引:0,他引:1
本文回顾了钛及钛合金熔模铸造的历史,通过对传统的真空电弧凝壳铸造法与新型的感应凝壳铸造法的比较,指出了该方法无需制作电极即可得到成分均匀的高质量铸件,并且消除了坩埚材料对炉料的污染,有助于产品获得理想的成分均匀性和准确性. 相似文献
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黄铜是一种常用的铸造合金。本文介绍了材质为ZH85黄铜的电极平头铸造工艺特点。通过这个成功的实例,笔者对怎样提高黄铜铸件的内在质量谈了几点看法。还介绍了一种防止镶铸件产生气孔等缺陷的简易方法。 相似文献
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电渣熔铸是一种将精炼和成形相结合的技术,在实际生产中既要充分发挥它在材料提纯精炼方面的优势,又要兼顾生产效率和生产成本等因素,因此是一个典型的多目标组合优化的问题。为此,提出了用电极锥头提纯系数、自耗电极熔化率和有效功率因数3个指标作为最终优化目标,以熔铸电流、渣池深度和冷却水流量为设计变量,基于人工神经网络和遗传算法理论,在Matlab平台上建立了电渣熔铸工艺参数的多目标优化系统,较好地协调了3个指标的相互关系,并预测了最佳的工艺参数组合。 相似文献
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本文采用旋转圆盘——圆环电极研究了黄铜(Cu37Zn)在1N Na_2SO_4及0.5N NaCl溶液中的阳极溶解行为。分别测出了黄铜阳极溶解时铜和锌的阳极溶解分电流密度。实验结果表明,Cu37Zn在上述两种介质中阳极溶解时均存在脱锌现象。在1N Na_2SO_4溶液中测得的脱锌系数强烈地依赖于阳极电位,而在0.5N NaCl溶液中,其脱锌系数与阳极电位的关系不明显。由黄铜中铜和锌的阳极极化曲线外推计算出了黄铜阳极溶解时锌和铜的腐蚀分电流密度,在1N Na_2SO_4溶液中分别为0.089及3×10~(-5)μA/cm~2,在0.5N NaCl溶液中分别为3.6及1.6μA/cm~2。实验还表明,黄铜在上述介质中的阳极溶解过程由扩散步骤所控制。 相似文献
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《Synthetic Metals》2005,155(3):480-484
The factors influencing the reduced open circuit voltage (OCV) of a Zn–polyaniline (PANI) rechargeable battery were investigated. The reduced OCV of battery at various number of charge/discharge cycles was measured and its relevance to the zinc anode and polymeric cathode was investigated. The results revealed that the battery OCV is reduced with the number of charge/discharge cycles. The composition of cathode surface and nature of electrolyte solution were evaluated by using scanning electron microscope (SEM) and spectrofluorimetric measurements, respectively. The decreased OCV was found cause by the cathode electrode. Although the SEM analysis showed that some zinc particles are adsorbed on the polymeric cathode electrode, this factor was not a major factor contribution to the OCV reduction. The spectrofluorimetric analysis of electrolyte solution revealed its increased hydroquinone (HQ) content with increasing charge/discharge cycles, as a result of the electrochemical degradation of the charged polyaniline. Consequently, the OCV of Zn–PANI rechargeable battery is reduced by chemical redox reaction of charged PANI with HQ. 相似文献
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采用SEM,EDS和XRD研究了几种Mg-Al-Zn合金的成分、相组成与凝固路径的关系.结果表明,Mg-Al-Zn合金的相组成与Zn/Al质量比有关;随着Zn/Al比值的增加,第二相γ Mg_(17)Al_(12)的数量减少,逐渐被φ-Mg_(21)(Zn,Al)_(17)取代,直至完全消失.通过搜集合金中町能存在的各相的热力学模型,运用Pandat热力学计算软件平台,计算并比较了平衡和非平衡(Scheil模型及金属型铸造)条件下合金的成分、相组成与凝固路径的关系.结果表明,金属型铸造的凝固过程偏离平衡凝固过程,Scheil模饿很好地解释了大多数合金铸造组织的相组成;但是由于Scheil模型不考虑有同相作为反应物参与的包晶反应,对ZA65合金凝固路径和相组成的预测结果与实际铸造组织的柑组成不符. 相似文献
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AZ31 alloy billets of 200 mm in diameter were produced by three different processes of conventional direct chill(DC) casting,low-frequency electromagnetic casting(LFEC) and low-frequency electromagnetic vibration casting(LFEVC),respectively.The effect of LFEC and LFEVC on the microstructures,macrosegregation and mechanical properties of AZ31 alloy billets was investigated.In conventional DC casting,the AZ31 alloy billets exhibited coarse grains(about 370 μm) and severe segregation of Al and Zn.In the presence of a solo low-frequency alternating magnetic field or a low-frequency electromagnetic vibration field applied during DC casting of φ200 mm AZ31 billets,grains in the AZ31 alloy billets were effectively refined(about 210 μm) and the macrosegregation of Al and Zn in the billets was greatly decreased.Furthermore,the tensile strength,fracture elongation and hardness of the as-cast AZ31 alloy billets were improved by the processes of LFEC and LFEVC relative to that cast by the process of conventional DC casting. 相似文献
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Metals and Materials International - In this study, Al-5Zn, Al-15Zn, Al-25Zn and Al-35Zn alloys containing 5, 15, 25 and 35 wt% Zn, respectively were produced by permanent mold casting.... 相似文献