提高铸造高温合金及其精铸件纯度洁度的途径

铸造高温合金及其精铸件纯洁度是我国合金及精精铸件生产中存在的极为重要的技术问题。它不仅影响到合金的性能水平及其稳定性，而且还影响零件的质量和合格率，引起了冶金工作的关注。本文对从原材料到工艺，从合金锭到铸件中存在的气体，杂质的影响作了分析，提出了应确定的技术要求和所能达到的措施，以进一步改善合金的冶金质量和提高铸件的合格率。     

新型钛精铸氧化物陶瓷型壳工艺研究EI

叙述了一种适合于制造薄壁钛合金精密铸件的新型制壳工艺，研究试验了型壳面层用稳定的氧化物耐火材料和稀土粘结剂，分析讨论了新工艺所浇铸的钛精铸件的冶金质量与性能。     

石墨铸型材料对钛合金内环铸件冶金质量的影响研究

目的研究不同石墨铸型材料对钛合金内环铸件冶金质量的影响。方法试验选取颗粒直径分别2,0.8,0.04 mm的3种典型石墨材料,制备内环石墨铸型,采用离心浇注,然后对3种不同石墨材质研制的ZTC4钛合金铸件进行表面目视检验、荧光和X光检测。结果 2,0.8,0.04 mm这3种颗粒直径的石墨铸型材质研制的铸件表面外观和荧光质量依次提高,其中荧光缺陷平均数量依次为21.4,13.9,2.2个/件;铸件内部缺陷数量均小于1.5个/件,夹杂均小于0.7个/件。结论不同颗粒度直径的石墨铸型对铸件的外观和荧光质量会产生显著的影响,而对铸件内部冶金质量影响较小。     

铸造高温合金精铸零部件的补焊研究进展

主要综述了采用钨极氩弧焊、激光焊、钎焊与粉末冶金修复再制造等焊接方式进行高温合金精铸件的补焊的研究现状及发展趋势.总结了采用不同补焊方法时焊接工艺对焊接性能的影响.指出了今后铸造高温合金精铸件的补焊的研究方向.     

精密铸造技术的最新发展

精密铸造技术的发展已有很长的历史。若从失蜡工艺算起,精铸技术很早以前就已用来制作雕像、工艺品和珠宝首饰了。现代精铸技术最显著的发展,在于工艺的改进,使用常规的铸造技术就能生产钛、锆及其合金。     

背层浆中添加物对精铸毛胚重量的影响

试验考察了硅溶胶精铸型壳的背层浆中加入高温焙烧易挥发性添加物对精铸件重量及其分布的影响。结果表明,背层浆中加入添加物对精铸胚重量及其分布具有较大的影响。当添加物的用量为硅溶胶胶粘剂总量的6.0%(w)时,浇铸精铸胚的重量具有最佳的集中分布,解决了精铸胚重量分布过于分散,铸胚出现轻品和超重的问题。     

钛合金大型薄壁壳体结构件的精密铸造

本文叙述了采用金属层面陶瓷型壳工艺，研制大型薄壁壳体类钛合金金精铸件，采用合适的工必离心浇注方法，获得了尺寸精确，表面光洁的铸件，采用热等静压处理，消除了铸件的内部缺陷，满足了承受高工作的压力的要求，铸件作为重要结构件已获得应用。     

本刊1981年1—6期目录索引

美国宇航总局(NASA)材料研究简况 关于航空材料及热工艺发展中的一些展望 材料应用 复合材料的质量控制 关于飞机重要受力构件采用精铸件可能性的探讨 ZM7合金在轮毅铸件上的应用 K6铸造镍基高温合金一种新型耐海水腐蚀的铝合金板材液压泵油缸转子的双金属浇注金相分析铝一铜系铸造合金热强性的研究DYB一3和DYB一4定向有机玻璃的力学性能福对ZL一205铸造铝合金时效组织结构和抗拉强度的影响K3合金的G相及其控制定向凝固涡轮叶片合金DZ22镍铬铝轴尖合金的试验与应用XZ一1室温硫化灌注料新型无机粘结固化涂层脂肪族聚氨醋飞机蒙皮磁…     

钛合金熔模精密铸件表面微裂纹形成过程研究

目的 表征钛合金熔模精密铸件表面组织的特性,研究其如何形成表面微裂纹的过程。方法 通过对钛合金精铸件表面微裂纹形貌进行观察,对表面α层的化学成分、显微硬度进行表征,并通过三点弯曲实验模拟α层在拉应力状态下开裂倾向。结果 微裂纹为冷裂,深度在α层范围内。α层的片层组织较铸件内部组织粗大,O含量和硬度高于铸件内部,在拉应力状态下较铸件内部容易导致裂纹萌生和扩展。结论 钛合金精铸件在凝固过程形成α层,在后续的冷却过程中形成的拉应力或翘曲变形导致相对脆弱的α层形成了表面微裂纹。     

热等静压在铸造高温合金领域的应用

采用适当热等静压工艺处理铸造高温合金,利用高温高压实现铸件内部疏松孔洞的蠕变扩散,达到闭合疏松和均匀合金组织的目的,使铸造高温合金的综合力学性能,尤其是疲劳性能、塑性及合金力学性能的稳定性显著提高,大大提高了铸件使用的安全性和可靠性.介绍了热等静压工艺处理高温合金铸件的致密化原理、工艺因素及其对合金组织和性能的影响,同时概述了热等静压技术的应用成果及发展状况.     

数值模拟在整铸涡轮精密成形中的应用现状

随着计算方法和铸造工艺的发展,数值模拟技术在铸造领域中得到了广泛应用.涡轮作为发动机上的重要热端部件,其结构伴随着发动机的更新换代,向着精密化、轻量化、薄壁化方向发展,数值模拟技术也成为铸造工作者控制涡轮质量的重要手段.目前相关学者通过铸造模拟软件对涡轮精密成形的充型过程与宏观物理场结果进行分析,依据模拟结果来改善铸造...     

模具定量精确成形技术在挤铸生产中的应用 研究

目的解决小型铝合金挤压铸件在浇铸过程中,存在的浇铸质量误差大、铸件组织的一致性较差、热节区出现组织缩松的问题,同时提高材料利用率。方法将模具定量精确成形技术引入到实际生产。结论模具定量精确成形技术的应用,能够有效解决小型铝合金挤压铸件在浇铸过程中因浇铸质量误差大的问题,铸件的总体质量误差能够控制在±0.02 kg范围以内,有效解决了因铸件质量误差大造成的铸件壁厚误差大,解决了铸件组织的一致性较差、热节区出现组织缩松的问题,提高了材料的利用率。     

RLS耐热铸造不锈钢燃烧器精密制造

RLS燃烧器是石油高新加热装备中的最核心关建零部件,铸件材质为耐热铸造不锈钢。燃烧器的内部形为状环状,是一个有8条细长窄缝的环形封闭室的压力容器,它的结构比较特殊,铸件壁厚也不均。而使用硅溶胶精密铸造工艺铸造,受熔模精密铸造工艺的局限性,模具制造、蜡件制造、模壳制造、铸件清理的制造工艺难度太大,产品的成功率很低。本文通过对铸件的铸造工艺性分析,汽腔被分割设计成汽腔芯和汽腔体,巧妙设计了汽腔芯的8条细长窄缝模具和制模工艺。通过先分后合工艺方法,解决了耐热铸造不锈钢燃烧器环形封闭汽室的细长窄缝蜡件和铸件的制造问题,使产品满足了要求。     

Effect of cast and extruded stock on grain structure of EN AW 6082 alloy forgings

Abstract

There has been a rapid increase in the use of aluminium forgings in the automotive industry, where weight savings is a critical requirement for reduced fuel consumption and exhaust emissions. Extruded bar is the typical forging stock particularly in the manufacture of suspension components. There has been a great interest to replace the extruded forging stock with cast billets of the same diameter. The casting and extrusion routes for the manufacture of EN AW 6082 alloy forging stock were compared in the present work. The control arm produced via forging of the cast stock offers a very uniform grain structure and much superior surface quality with respect to its counterpart produced by the forging of the extruded stock owing to a much smaller grain structure at the surface of the forged component after the T6 heat treatment.     

ProCAST软件在铸造凝固模拟中的应用

为研究铸造工艺对铸件质量的影响,利用计算机进行了铸件的凝固模拟.介绍了有限元软件Pro-CAST的组成模块、功能以及应用,在应用实例中利用ProCAST软件模拟预测了铸件砂铸工艺中产生的宏观缩孔缺陷.研究表明:铸件中存在模拟预测的宏观缩孔缺陷;对浇注系统和冒口设置参数进行了优化,优化后的工艺提高了铸件产量,降低了成本;模拟结果表明,铸造模拟软件ProCAST能够准确地预测铸件在充型凝固过程中可能产生的缺陷.     

Study on the possibility of continuous-casting of bimetallic components in condition of direct connection of metals in a liquid state

The possibility of producing bimetals by continuous casting method when composition of components occurs in liquid state without mixing is considered. Contact layers of composite metals were investigated by methods of metallographic, X-ray diffraction, microscopic and ultrasonic analyses. Binary mixtures of eutectic type Al–Zn, Al–Sn, Al–Pb were selected. The numerical estimations for bimetallic casting of some metal-alloy pairs were also conducted to achieve the optimization of casting process condition.It was observed that the size of diffusion zone of interface layer was 0.1–0.5 mm in producing bimetallic compositions by direct connection of liquid phase components. The microstructures observed in bimetallic binary samples were well accorded to those expected from the phase diagrams. It could be concluded from the mathematical simulation for casting process that qualified bimetallic casting billet and plate can be continuously cast by carefully controlling the casting process condition such as withdrawing speed.     

镶铸管铸造工艺铸件无损检测分析

目的 研究镶铸工艺成形钛合金铸件镶铸部位冶金缺陷形成原因及无损检测表征,为镶铸工艺铸件的无损检验判定提供依据,并为此类产品冶金质量评价提供依据,建立质量评价体系标准。方法 通过对采用镶铸钛管工艺成形铸件的镶铸部位进行X射线检测及微观形貌、成分检测,结合铸造成形工艺的数值模拟过程进行对比分析。结果 预埋钛管表面在铸造工艺过程中出现表面氧化,浇注过程中,在镶铸部位存在多股金属液充型交汇,镶铸管部位结构融合效果存在差异,存在未融合现象。结论 采用镶铸工艺制备的铸件在无损检测方面存在不同于传统的冶金评判特征,镶铸部位的未融合缺陷可以通过X射线检测发现,在X光底片显示为沿钛管界面的黑线。     

A System of Process Models for Estimating Parameters of Continuous Casting Using Near Solidus Properties of Steel

The quality of a continuously cast product depends on the process condition, which, in turn, depends on process parameters. To be able to set the correct parameter values, it is important that behavior of the steel being cast under different casting conditions is well understood. This will need the knowledge of the mechanical behavior of steels at temperatures near the solidus. This paper presents, in detail, how these properties were modeled as a function of steel grade, temperature, and stresses that arise during casting. These models have been used to develop an integrated system that is capable of simulating various process conditions that may be encountered during continuous casting. The details of how these models were developed, verified, and used to develop the integrated system are presented in this paper.     

复杂铝合金结构件复合型整体精密铸造方法研究

以某电子舱铸件为例,阐述了一种复合型芯整体精密铸造方法.铸造时,壁薄难成形的部位采用熔模壳型,保证其充型完整;其他部位采用树脂砂型,保证其冶金质量和尺寸精度,从而获得了外形完整、组织致密、尺寸精度高的整体电子舱铸件.     

Use of vacuum for counter-gravity casting of metals

 The use of vacuum to fill molds to form investment castings in a countergravity casting fashion was started in the early 1970s. This paper describes how the processes work and the reasons for their advantages in cost, quality, and process control. Countergravity casting is being done in sand, permanent, and investment (lost wax) ceramic molds and alloys are cast in air and inert atmospheres. The process started with common steels, was extended to heat resistant superalloys, and recently even titanium alloys are being cast routinely using ceramic crucibles. The use of a unique mold design enables a great reduction in metal cast to yield a given part, thereby greatly reducing the energy use in making such castings. Computerized control of the rate of vacuum application enables complete control of filling rates, permitting casting of very high quality castings in very viscuous metals, such as metal matrix composites of aluminum. These processes are used to produce more than $200  million worth of castings annually and this will greatly increase in the next few years due to the production of automotive exhaust manifolds in stainless steel. Received: 21 July 1998 / Accepted: 10 September 1998