精密铸造硅溶胶模壳的制造工艺

介绍用石蜡-硬脂酸低温模料，生产铸件的熔模和用精密铸造硅溶胶，作为制壳粘结刑，制造铸件的模壳的工艺要求。主要研究熔模制造工艺、硅溶胶模壳工艺和焙烧工艺。五年多来的生产实践充分证明精密铸造硅溶胶模壳制造工艺是成熟的。为生产合格模壳和精密铸件提供了技术保障。     

聚乙烯蜡-硅溶胶熔模铸造工艺

介绍了用聚乙烯蜡低温模料制作熔模、用硅溶胶作粘结剂制造型壳的工艺.多年生产实践证明,采用聚乙烯蜡制模的硅溶胶型壳制造工艺是成熟的,可以达到减少污染、降低成本的效果.     

熔模精铸机车类铸件生产工艺

介绍了机车类铸件的熔模精铸工艺.采用低分子聚乙烯蜡中低温模料制作熔模,用硅溶胶粘结剂制造型壳,工艺简单,污染少,成本低,铸件质量好,满足机车类精铸件生产要求.     

摆杆铸件的熔模精密铸造工艺实践

采用石蜡-硬脂酸低温模料制造熔模(蜡模),用水玻璃粘结剂制造型壳,精密铸造生产剪羊毛机摆杆铸件,试验研究熔模制造工艺、水玻璃型壳工艺和焙烧工艺的技术参数,为生产合格型壳和精密铸件提供技术保障.     

石膏型熔模精铸水性硅溶胶制壳工艺研究

以石膏型熔模精铸生产金属工艺品为例,在制壳工艺中以水性硅溶胶代替水作为粘结剂来增强石膏型壳的透气性,提高石膏型壳的力学性能,有效地阻止了石膏型壳的开裂。以水性硅溶胶作为粘结剂的石膏型熔模精铸生产的铸件,形状完整、轮廓清晰、表面质量更好。     

石膏型铜合金精密铸造研究

采用快速成型(RP)制备复杂型腔薄壁蜡模并对其进行铜合金石膏型熔模精密铸造。结果表明,与传统硅溶胶工艺条件下铸造的铜合金件相比,铜合金石膏型精密铸件的外观品质、尺寸精度和尺寸稳定性略有提高,仅力学性能有轻微下降。对于薄壁复杂类、型腔较深类、异型类、截面多变类铜合金铸件,由于硅溶胶工艺制壳的铸件清理难度加大,石膏型精密铸造显得尤为重要,其制壳工艺、后期清理成本和效率明显提高。     

不锈钢法兰弯管精密铸造技术

LB90、U型不锈钢法兰弯管采用精密铸造生产。通过试验研究,对蜡模进行分体设计制造,弯头精密铸造模具采用圆环状旋转抽芯机构,蜡模装配采用组合夹具定位组装,采用硅溶胶熔模精密铸造工艺,提高了LB90、U型304不锈钢法兰弯管的铸件制造精度,简化了生产工艺。     

我国熔模精密铸造的历史回顾与发展展望

概述了熔模精密铸造的特点及在我国的整体发展现状。按照不同产品类别追溯了我国熔模铸造发展的历史、技术进展、行业现状。详细介绍了通用硅溶胶型壳工艺、钛合金熔模铸造工艺、铝合金熔模铸造工艺、石膏型熔模铸造工艺、水玻璃型壳工艺等多种工艺方法以及熔模精密铸造在航空、航天以及一般商用铸件上的应用。指出了我国熔模精密铸造与工业发达国家之间存在的差距,并对我国熔模精密铸造行业的发展提出了几点建议。     

改善硅溶胶涂料涂挂性的方法

硅溶胶是一种新型的水基粘结剂。由于它与硅酸乙酯相比具有制造容易、使用简便、能节约大量乙醇、不易燃烧、涂料存放期长、壳型烧结强度高和抗热变形能力好等优点,因而,近几年来,在熔模精密铸造上的应用日益广泛。 但是,作为一种水基粘结剂的硅溶胶也带来了两个难以避免的缺点,就是用它配制的涂料涂挂性差和干燥缓慢。尤其是在涂挂性方面,硅溶胶涂料表面张力大,对蜡模浸润性差;产生气泡难以排除和涂料流动性不好,粘度较大。为了保证铸件表面质量,必     

硅溶胶与硅酸乙酯复合型壳探讨：缩短硅溶胶制壳周期方法之一

探讨用硅溶胶与硅酸乙酯制造复合型壳的工艺，选择出层间干燥时间等参数，为生产使用提供了科学依据。复合型壳代替硅溶胶型壳可大大缩短制壳生产周期。     

快速成形技术在铸造模具制造中的应用

介绍了各种快速成形技术的工艺原理,详细分析了快速成形技术在铸造模(如木模、蜡模、消失模、覆膜砂型(芯)、陶瓷型壳、铸造金属模等)制造过程中的具体应用,讨论了快速成形技术的发展方向。     

球铁管件真空消失模壳型复合铸造工艺的研究

比较了真空消失模铸造和熔模铸造两种工艺的优缺点,将两种工艺的优点有机结合,开发了适应大量生产高性能出口管件的真空消失模壳型复合铸造工艺.介绍了消失模铸造模型刚度的确定、浇注系统尺寸的选择,壳型工艺流程的制订、壳型涂料的原材料选用和配制、以及水玻璃壳型制造流程.试验结果显示:(1)用此工艺生产的管件,工序简单且铸件质最稳定,铸件合格率达到98.5％以上;(2)此工艺只要制4层壳,相比普通蜡模精密铸造制壳要8层以上,提高了生产效率,降低了生产成本和人力资源成本.     

Mullite shell mould for casting of advanced CG and SX components in nickel based superalloys

Abstract

Mullite base shell mould system is used for casting of superalloys in columnar and single crystal grains in temperature range of 1480–1550°C. The colloidal silica gel+mullite filler with and without fine alumina slurries was prepared followed by two shell moulds: one without alumina (shell system I) and the other with alumina (shell system II). Shell made with slurry system II resulted in increase in green strength by 10% and fired (950°C) strength by 125% respectively. Sag resistance capability was observed more for shell system II for tested temperatures from 1500 to 1650°C. Dimensional stability of low pressure turbine blade cast at 1550°C was also studied. No shell bulging effect was observed for both shell moulds. The importance of mullite filler material for shell mould to be used for investment casting and its capability to withstand high temperature without metal mould reaction have been highlighted.     

壳型铸造用覆膜砂若干技术问题探讨

根据壳型生产线十几年运行和各类覆膜砂应用的经验,对壳型铸造用覆膜砂的一些技术问题进行探讨。详细介绍适用于吹砂式多工位壳型机的湿态覆膜砂性能;高强度低树脂量覆膜砂的研制;湿态壳型覆膜砂的成形性指数与调湿工艺;翻斗法制壳时的脱壳问题分析和解决办法;覆膜砂脱壳性检测方法;高镍球铁件壳型铸造表面针孔原因分析与抗针孔覆膜砂的应用。     

农机小齿轮及齿圈的精铸工艺

采用中温蜡料、硅溶胶型壳的精铸工艺生产农机用碳钢小齿轮及齿圈.介绍了铸件生产的技术难点、生产条件、模具设计、制壳、熔炼及浇注工艺.经验证,生产的铸件质量好,废品率低,可直接用于装配,说明该工艺合理可行,不仅提高了材料的利用率,降低了生产成本,还提高了生产效率.     

熔炼铸造型壳废弃物组成及其再利用分析

对水玻璃型壳、硅胶型壳及复合型壳等熔模铸造常用的废弃物组成进行了分析，并以此为基础提出了型壳废弃物资源化利用的一些途径。     

用快速精密铸造工艺铸造叶轮发泡模具

开发了一种叶轮发泡模具的快速精密铸造工艺.在铸造工艺中,利用快速成型技术和复合陶瓷型壳技术来制备叶轮的精密铸造型壳.用该铸造工艺铸造的叶轮发泡模具具有尺寸精度高、表面光洁度好的特点,可满足叶轮发泡模具的使用要求.     

Research on cracking mechanism of the thin shell mould in expendable pattern shell casting during pattern removal process

Aiming at the cracking phenomenon of the thin shell mould in the expendable pattern shell casting during the pattern removing process, some systemic researches are presented.The influence of the pattern removing method and temperature on the pattern removing were investigated.The shell mould cracking mechanism was analyzed by using thermo-gravimetric analysis (TGA), and combining the temperature field and the volume change of the expanded polystyrene (EPS) foam pattern being tested.The results indicated that the shell mould was not easily cracked when the pattern removing process was carried out with the furnace being heated little by little because of the shell slowly shrinking with dehydration and shell strength gradually increasing.The shell mould was soon destroyed when it was set directly into the furnace at above 400 oC because of the thin shell mould rapidly shrinking and the foam pattern hindering.However, the shell mould had no cracking when it had been preheated for a long time even if the furnace temperature was above 400 oC and the shell was put into the furnace directly.Moreover, when the shell mould was directly set into the furnace at lower temperatures, 250 to 300 ℃, the shell would shrink slowly and the foam pattern would stay at the maximum expansion stage temperature of 100 to 110 ℃ for a long time; and the shell mould would experience an expansion force from the foam pattern for a long time.The expansion force is related to the pattern removing temperature, holding time, foam pattern thickness and density.Therefore, the foam pattern with higher density could make the shell crack.