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.     

一种医用钛合金铸件熔模铸造工艺设计

一种医用钛合金铸件采用ZTC4钛合金,由熔模铸造工艺生产.通过对浇注系统进行模拟分析,确定适用于生产该医用钛合金铸件的浇注系统.面层采用1#粘结剂制壳工艺、加固层硅溶胶制壳工艺,采用蒸汽脱蜡及合适的焙烧工艺、离心浇注工艺获得医用钛合金铸件,铸件经过修整、热等静压等工序获得了内部及外观质量好、尺寸精度高的钛合金铸件,批量...     

支架类铸件熔模铸造工艺研究

介绍了支架类铸件熔模铸造的工艺路线及主要工艺方案。通过合理制定铸件的制模、浇注系统组合、制壳、浇注等工艺方案,解决了铸件在生产过程中出现的疏松、冷隔、变形等铸造缺陷。改进后的工艺不但提升了产品质量,而且可为同类铸件的熔模铸造工艺提供参考。     

涂料成芯精铸空心叶片铸件

阐述了不用陶瓷型芯而采用正常涂挂涂料，撒砂等工序成芯熔模铸造空心叶片铸件的工艺特点及在制模，制壳和熔炼浇注等关键工序中应重点解决的问题。     

型壳分层对熔模铸件质量的影响与对策研究

在熔模铸造工艺中,对铸件质量影响最严重的环节是制壳工序,而其中最难控制的又是型壳分层问题。本文就分层形成原因、诸因素相互作用、生产中的工艺对策等方面进行了较全面的阐述。     

三通铸件精铸工艺改进

三通铸件精铸工艺改进宝鸡石油机械厂李显文我厂熔模铸造采用水玻璃粘结剂，石英砂耐火材料，ＮＨ４Ｃｌ硬化剂制壳。由于生产的品种多，数量少，现场大量采用石膏模具压制蜡模，金属模具使用在批量多、表面精度要求高的精密铸件上。我厂接到出口产品上的三通铸件任务，考...     

硅溶胶型壳的干燥和硬化

在熔模铸造制壳工艺中,用去除溶剂使得涂料凝结的方法,称为“干燥”,用电介质或酸碱中和促使胶凝的方法,叫做“硬化”。干燥和硬化效果的好坏,对型壳和铸件质量有决定性的影响。 硅溶胶型壳干燥和硬化的方法很多,但迄今为止,最普遍的干燥方法仍然是强制通风干燥。这种干燥方法设备简单,易于采用     

熔模铸造的自动化制壳生产线

根据熔模铸造自动化制壳生产线的结构特点,从涂挂和撒砂均匀性比较了手工操作和机器操作的区别,分析了型壳强度的影响因素.结果表明,在熔模铸造工艺过程中运用自动化生产线制壳,可以减少生产过程中人为因素的影响,提高型壳强度,保证铸件质量,同时改善了工人劳动强度,提高了劳动生产率.     

熔模铸造水玻璃型壳性能预测系统的开发

1 前言 水玻璃目前仍然是国内熔模铸造中使用最多的制壳粘结剂,国内对水玻璃型壳已进行了大量研究,对于各种不同工艺因素对水玻璃型壳性能的影响已经有了比较充分的认识。但是熔模铸造工作者更希望能直接量化型壳的性能,以便通过性能预测控制制壳过程,帮助分析废品产生原因,提高铸件质量。为此,本文在水玻璃型壳强度研究的基础上,进一步开发了熔模铸造水玻璃型壳性能的预测系统。     

大型复杂钛合金铸件熔模精密铸造技术

钛合金熔模铸造工艺过程复杂,影响铸件质量的因素较多,而大型复杂钛合金熔模精密铸造技术是铸造行业的前沿技术.文中介绍了大型复杂钛合金熔模铸造技术的国内发展现状,详细论述了铸件尺寸精度及铸件质量控制的技术难点及应对措施.结合大型复杂铸件离心铸造生产实际,对关键过程的质量影响因素进行全面分析,从制模、制壳、熔铸等工艺过程阐述...     

Evaluation of crucible and investment materials for lost wax investment casting of Ti and NiTi alloys

Abstract

The aim of this study is to assess the suitability of selected commercial ceramic crucibles for the investment casting of Ti6Al4V and NiTi alloys for jewellery purposes. A commercial vacuum tilt casting machine and a centrifugal casting machine were employed to cast the alloys in cold copper moulds or in refractory investment shells. The form filling of the shell and the crucible and investment reactions were assessed by microstructural investigation, chemical analysis and hardness profiles of the as cast items as a function of shell temperature. The reaction of the alloys strongly depended on the alloy, the crucible material, the coating of the crucibles and the temperature of the ceramic shell. Optimum results were achieved with yttria and yttria coated Al titanate crucibles for Ti6Al4V and NiTi alloys respectively. Improvement of the materials and process costs is necessary to allow the competitive casting of jewellery made from titanium alloys.     

射压造型(DISA线)用金属模具的快速制造

介绍了DISA线壳体模具的快速制造工艺过程，即在三维造型和快速原型制造的基础上，结合转移涂料精密铸造工艺，实现铸铁模具的快速制造。此种制造工艺具有速度快、成本低、模具精度高等优点，适合在模具制造行业中推广应用。     

精密铸造马氏体铬型不锈钢麻点缺陷的解决方案

熔模铸造马氏体铬型不锈钢表面极易产生麻点,是常见并较难解决的铸造缺陷。根据麻点的形成原因,进行了不同的试验方案,分析麻点缺陷形成原因,提出两种解决措施,一是采用专用磁选设备对制壳材料进行磁选,以减少磁性氧化物;二是在制壳过程中,采用鳞片石墨砂做为过渡层,既能制造还原性气氛又能阻挡硅酸铁渗透,有效避免了麻点的产生。     

Interface reaction during titanium alloys investment casting by residue gas in ceramic mold

The chemical reaction between mold material and titanium melt during investment casting was studied intensively. However, the influence of residue gas in ceramic mold on interface reaction remains unclear. In this investigation, the effect of residue gas in Y_2O_3-silica sol shell mold on interface reaction during Ti-6Al-4V alloy investment casting was investigated. Two groups of shell molds were prepared by adding different kinds of pore formers, i.e., spherical starch particles or nylon fibers,respectively. Ti-6Al-4V alloy was cast under vacuum by gravity casting through cold crucible induction melting(CCIM) method. Porosity of different shell molds was measured based on Archimedean method. Scanning electron microscopy(SEM) and energy-dispersive X-ray spectroscopy(EDS) were employed to characterize the micromorphology and composition of the reaction area,respectively. White light interferometer(WLI) was used to obtain the surface topography of the shell mold. The results show that the direct chemical reaction is very weak for all specimens. The release of residue gas in closed pores is the key factor influencing surface defects. However, open pores make nearly no difference on the interface reaction.     

硅酸乙酯-水玻璃复合型壳在精密铸造中的应用

介绍了硅酸乙酯-水玻璃涂料的配制过程及复合型壳工艺。复合型壳工艺用于精铸件的生产,面层、第二层用硅酸乙酯石英粉涂料,从第三层开始采用水玻璃石英粉、铝矾土涂料。结果表明,与原水玻璃型壳相比,硅酸乙酯-水玻璃复合型壳强度好,尤其表面质量好,铸件的表面粗糙度达到Ra3.2左右,在成本增加不大的情况下,能较大幅度的提高铸件的综合性能,表现出了良好的综合效益。该工艺较适合于原来水玻璃型壳旧工艺、旧车间的技术改造。     

国际熔模铸造工艺近况

介绍了国际熔模铸造工业的市场现状和展望；综述了制模，制壳，金属熔炼及计算机应用等方面的技术发展状况。     

无余量薄壁叶片的精密铸造

应用硅熔胶粘结剂涂料制造型壳,进行高温合金无余量薄壁叶片的生产,由于型壳强度高,造成叶片边缘产生裂纹而报废,通过生产过程中造成铸造叶片裂纹产生原因的分析,有针对性地提出复合涂料制壳的生产工艺,并使其在生产中得到应用     

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.     

铜粉处理对涂料导电性能的影响

金属铜粉由于它具有固有的光泽、良好的导电性和低廉的价格，作为导电涂料的填料引起了人们的关注。但铜较活泼，容易被氧化。在贮存和运用过程中，铜粉表面容易形成Cu2O和CuO不导电薄膜，这给铜粉的使用带来了障碍。在铜粉表面包覆硬膜酸是防止铜粉氧化而实施的一种方法，但硬脂酸是一种不导电的有机物，这给制备导电涂料带来了不便。针对以上两种情况，本文探讨了对表面部分氧化的铜粉和包覆有硬脂酸的铜粉的处理方法，以及它们对涂料导电性的影响。