真空对触变压铸铸件力学性能的影响

讨论真空辅助工艺对两种浇道系统 (扇形单浇道和分支浇道 )铸件的力学性能和微观结构的影响 ;经比较真空和无真空条件的区别 ,得到结果是真空对扇形单浇道系统铸件的气孔影响大 ,而对分支浇道系统铸件的气孔影响小。     

高真空压铸汽车底盘结构件浇注系统分析

介绍了汽车底盘结构件的高真空压铸成形设计,以可热处理的Al-Si-Mn-Mg系高强韧铝合金汽车底盘结构件的压铸技术开发与应用为研究对象,通过设置不同的浇注系统,应用数值模拟方法,定性分析了铝合金液流动的充型状态与铸件缺陷的分布,着重研究了梳形浇道、扇形浇道、集中进浇、分散进浇、长浇道与短浇道对充型流动状态、充型温度、充型速度、气压阻力与铸件成形的关系;确定了铸件的浇注系统与排气系统,大大缩短了模具的开发周期。     

列车箱体铸铁件表面气孔缺陷的消除

针对列车箱体铸铁件上表面存在的气孔缺陷,分析了原工艺存在的问题。应用大孔出流理论,重新设计了浇注系统,在铸件底部和顶部增加了内浇道,浇道面积加大1倍,结果气孔缺陷彻底消除。     

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。     

消除碳素钢精密铸件表面渣、气孔的措施

精密铸造生产中,碳素钢精密铸件因含碳量高,浇注过程中吸气、氧化严重,铸件表面容易出现渣、气孔,主要集中在组树方案中铸件的上表面,影响铸件的外观及质量.在常规方法不能完全解决的情况下,引入砂模铸造工艺设计方法,通过外加直浇道,钢水从外加直浇道中注入型壳,使钢水在型壳内平稳上升,产生的气及渣随同钢水通过内浇道顺利浮出铸件,避免组树方案中铸件上表面产生渣气孔,改善铸件表面质量,减少铸件后期的修补成本.     

铸型工艺特点对抑制球铁皮下气孔的有效作用(摘要)

通过φ９８～３０８五种盘形球铁铸件的生产实践，总结出防止皮下气孔的工艺措施：（１）不宜采用通过冒口集中进铁的浇注系统，宜采用带有多道内浇道进铁，横浇道设有阻流截面和集渣包的浇注系统，使铁液平稳充型，减少二次氧化和挡渣。（２）铸件冷速很慢或很快时都不容易产生皮下气孔，仅当冷速处于中间值时（厚为１０～２４ｍｍ时）最容易产生皮下气孔。因此，对较厚（＞２５ｍ）铸件，宜在浇注系统末端设置溢流胃口，进一步减慢冷却速度；对较薄（＜１０ｍｍ）铸件，则宜在铸件适当部位设置冷却片或敷设冷铁，进一步提高冷速。铸型工艺…     

圆柱类壳体铸件的金属型铸造工艺

在理论分析和生产验证的基础上,对内外质量要求较高的圆柱类铝合金壳体铸件,采用金属型铸造的工艺方法,阐述了在浇冒系统、排气系统、浇注等方面的工艺思想,尤以扁平扇形横浇道和环形内浇道的搭配设计可更加有效地排渣和热量的分散,效果良好.该工艺方法具有一定的推广意义.     

改变气体流向消除铸件气孔

作者论述了在湿型中建立-1kgf/cm~2的真空,改变砂型中气体的流向来消除铸件气孔.文中就各种因素(例如型砂水分、真空度、砂的粒度以及浇包抽真空等)对铸件形成气孔的影响进行了一系列试验研究.由于从砂型中抽走气体,因此能够完全消除气孔.     

首饰铸件浇注系统的优化设计

根据首饰铸件精密铸造工艺特点,对首饰铸件浇注系统中的浇口浇道进行分析.通过大量试验,发现浇口浇道大小、连接角度的设计对首饰铸件质量有较大的影响;针对首饰铸件模型的不同结构提出了不同的浇口浇道的设计方法,以消除铸件的各种缺陷,提高了铸件质量.     

横梁铸件的生产实践

分别从造型方法,浇注系统设计以及制芯工艺等方面介绍了横梁铸件的生产过程。分析了原工艺出现气孔缺陷的原因。采取了优化浇注系统及改进排气的措施,在浇注位置的最上面设计了两道内浇道,在出现气孔的部位增加了排气冒口,有效解决了铸件上表面的气孔缺陷。     

Reduced energy consumption by using streamlined gating systems

In foundries a lot of effort is done to minimize energy consumption in the production to reduce costs and hence increase the competitiveness. At the same time the foundries must live up to the increased demands for high quality castings. Traditional gating systems are known for a straight tapered down runner, a well base and 90° bends in the runner system. Previous work has shown that the traditional way of designing gating systems creates high inconsistency in flow patterns during filling. In the streamlined gating systems there are no sharp changes in direction and a large effort is done to confine and control the flow of the molten metal during mould filling. The main objective in the work presented here is to use the principles of the streamlined gating systems to reduce the weight of the gating system relative to the traditional layouts. By reducing the weight of gating system and thereby improving yield, the amount of molten iron needed is also reduced, hence reducing the energy consumption for melting. Experiments in real production lines have proven that it is possible to achieve a reduction in the poured weight by using the streamlined gating systems. In a layout for casting of three valve housings in a vertically parted mould the weight of the gating system was reduced by 1.1 kg changing from the traditional layouts to the streamlined gating systems. This weight reduction corresponds in this case to a 20% weight reduction for the gating system. Using streamlined gating systems with fan gates to give a beneficial heat distribution in the castings may be an efficient tool to eliminate the need for heat treatment. In the experiments the change in gating system from the traditional layout to the streamlined layout removed the need for heat treatment. This obviously means a huge energy saving in the foundry. The energy consumption for heat treatment of iron has been found to be 0.489 kWh/ kg. The valve housing in the experiments weighs 3 kg so when the need for heat treatment is removed, around 1.5 kWh     

Bifilm defects in ductile-iron support bracket castings

Many filling defects such as bi-film defect, gas bubble, loosed sand and etc., are developed by turbulent filling. These defects entrapped and flowed along mold cavity during the filling process. As a result, they makes casting property unreliable and unpredictable. The best way to prevent the filling defect is to control the gating velocity under a critical value using a bottom gating runner system. Two different gating system, top- and bottom- systems, are applied for casting ductile-iron support bracket. For these two runner systems, their filling defects are predicted by a numerical modeling. Two- and three- parameter Weibull probability are plotted to analyze the reliabilities of the mechanical properties of the castings from these two gating systems. A good and reliable runner system for casting a high elongation and fracture toughness of the support bracket was proposed in this study.     

基于Flow-3D摩托车轮毂压铸成型浇注系统优化设计

分析了摩托车后轮毂的结构特点,计算了压力铸造浇注系统的工艺参数,应用Flow-3D软件对金属液在不同浇注系统结构中的充填过程进行数值模拟。结果表明,采用单横浇道和单内浇口的浇注系统,会导致制件最终温度场不均匀,且在轴孔处聚集较大面积的氧化夹杂物;采用双横浇道和双内浇口,从轮毂的两个凸缘同时充填,可以保证零件的完整成型,且制件温度场均匀,避免产生氧化夹杂物,生产的摩托车后轮毂可满足质量要求。     

磨床导轨面铸造缺陷分析及预防措施

水玻璃砂铸型中残余水分是导致灰铁件产生皮下气孔和氧化夹渣等铸造缺陷的主要原因。合理地设计浇注系统,增加直浇道高度和出气冒口数量的同时,对砂芯进行烘干处理,可有效地减少铸造缺陷,提高铸件质量。     

微车转向节系列球铁铸件的壳型铸造

针对微车转向节系列球铁铸件的壳型铸造生产中,采用中注式浇注系统出现的渣孔、气孔、缩松等问题,增大排气道和浇、冒系统体积,改变铁水进入型腔的方向,选用合适的球化剂、球铁用生铁及辅料,铸件合格率由原来的50%左右提高到85%以上.     

油底壳铸件的工艺设计

针对砂型铸造生产大、中型薄壁油底壳类铝合金铸件,容易出现浇不足、夹渣、砂眼等铸造缺陷,根据多年生产实践经验总结,通过采用带过滤网的搭接式双向横浇道的浇注系统和组芯工艺,大大提高了铸件合格率,可以稳定生产出优质合格铸件.     

刹车鼓铸件缩松缺陷的防止措施

介绍了灰铸铁刹车鼓铸件的结构,详细阐述了该铸件的原生产工艺及在安装面根部出现的缩松缺陷.通过多方面的原因分析和生产试验,认为单个边冒口补缩能力范围有限是导致小端内圆根部缩松的主要原因.采取了以下措施:去掉边冒口,将铸件主体由上箱翻转至下箱,利用铁液重力补缩;浇注系统由底注改为顶注,提高内浇道的流量,降低铁液流速,采用浇...     

两类制造难度大的液压铸件的工艺设计

阐述了液压铸件生产制造中制造难度大的两类铸件的工艺设计方案。多路换向阀体铸件,采用了框架式芯头的型腔工艺设计方案,浇注系统采用热冒口,按照顺序凝固的原则,液态金属由直浇道、横浇道、挡渣浇道,经冒口流入铸件型腔。柱销式叶片泵配流盘铸件,采用了一种使型腔中所有油口在一个盘式芯头上整体成形的工艺设计方案,采用压边冒口,按照同时凝固的原则设计浇注系统。     

HT300液压件的消失模铸造

介绍了采用消失模铸造方法生产HT300液压铸件的工艺方法。试验和生产应用结果表明,通过选用含碳量低的模样材料,合理设计浇注系统,采用新开发的涂料,适度提高浇注温度和真空度等,能够生产出表面光洁、平整、棱角清晰且尺寸精度高的液压铸件。