高温合金薄壁密封片的精铸工艺

Investment Casting Process of a Superalloy Thin-Walled Seal Plate Casting

高温合金薄壁密封片是某型号航空发动机上的重要部件,采用无余量整体熔模精密铸造方法生产。该密封片为大尺寸薄壁铸件,长度约500 mm,壁厚为0.8-1 mm,并有多处加强筋和变截面。在铸造过程中极易变形并产生欠铸、裂纹和疏松等缺陷,铸造成形难度大,试制阶段产品合格率极低。采用蜡模和铸件的校形工艺,保证了铸件尺寸精度。结合亨金法计算和铸件结构特点,设计优化内浇道尺寸和位置,同时调整造型工艺,使铸件合格率大幅提高。

The superalloy thin-walled seal plate is the important component of the spaceflight engine, which was produced by investment casting. It is large and thin-walled casting with the length of 500 mm and the thickness of 0.8-1mm. The misrun, porosity and crack can be observed easily in the process of casting resulting in difficult metallurgical quality control and low qualified rate. By straightening of wax pattern and casting, the dimension precision is guaranteed. According to Heng Jen formula and casting structure, casting defects were effectively controlled and the casting qualified rate was significantly improved through optimizing gating system design, adjusting molding design.