K432A机匣部件精铸工艺研究

Research for Investment Casting of K423A Case

机匣是在研某型号航空发动机上的核心部件,采用铸造高温合金K423A无余量整体精密铸造而成。该部件由内环、外环和空心叶片三部分组成,壁厚相差悬殊,铸造凝固过程极易产生疏松、裂纹等缺陷,铸造难度很大。为确保精铸件的尺寸精度、缩短研制周期,采用了快速成型技术制造熔模,熔模经表面处理后具有良好的表面质量和尺寸精度,表面粗糙度可达Ra6.3μm,尺寸精度可控制在0.5mm以内。设计了联合注入式浇注系统,采用较高的浇注温度和型壳温度,浇注出的铸件冶金质量优良,很好地满足了设计和使用的要求。

The case, which is cast in K423A superalloy by investment casting, is one of the core components of the aeroengine. This component constituted of inner ring, outer ring and hollow vane, and the discrepancy of the wall thickness is great, the porosity and crack can be found easily in the process of casting, so it is very hard to produce. Considered the casting＇s complicate structure, the rapid prototyping technology was designed to produce the mould in order to meet the precision requirements and shorten the developing cycle. Once the mould surface was repaired, the roughness of the mould surface can arrive at Ra6.3 and the dimensional tolerance can be kept within 0.5 millimeter. With the united-inpouring gating system and high pouring and mould temperature, the casting is shaped with high metallurgical quality, which accords with the demands of the design and use entirely.