K487合金内涵尾喷管的精铸工艺

Investment Casting of K487 Inner-Tailpipe Nozzle

内涵尾喷管是某航天发动机的关键部件,采用可焊接铸造高温合金K487无余量整体精密铸造而成。内涵尾喷管铸件由内环、中环、外环、支撑板以及内层导向叶片组成,叶片最薄处仅为0.64mm。该铸件是结构复杂的薄壁件,因此在铸造凝固过程中极易产生疏松、裂纹等缺陷,铸造难度大。本研究采用了组合夹具精密定位、蜡模分体组合成型的工艺方案,获得高尺寸精度和高表面质量的蜡模;通过优化浇注系统和浇注工艺的方法获得高冶金质量的铸件,很好地满足了设计和使用的要求。

Inner-tailpipe nozzle, which cast by investmentcasting with superalloy K487, is one of the key components of the spaceflight engine. The casting is constitutive of an inner ring, a middle ring, an outer ring, shoe plates and inner-turning vanes, and the thinnest part of the vane is 0.64 mm. It generates porosity and crack easily during solidifying for its great complicated structure and its thin section, so it is hard to cast. The method of split pattern and combined clamp was used to get high precise dimension and high surface quality wax pattern, and through optimizing gating system and gating technology, high quality castings have been obtained, which satisfy the demands of the design and application entirely.