K439B高温合金薄壁机匣试验件熔模精铸缺陷预测与工艺优化研究

Predication of the Defects and Optimization of the Technology for the Investment Casting of Thin-wall Experimental Cartridge Receiver Made of K439B Superalloy

本文针对800℃可焊K439B铸造高温合金机匣试验件,采用ProCAST软件,利用基于Darcy定律发展的宏微观耦合缩孔、缩松模型对试验件熔模铸造的充型、凝固过程中的温度场和固相分数进行了数值模拟。结果表明,壁厚较薄铸件底部在凝固过程中存在孤立液相区,从而形成缩松、缩孔缺陷。进一步通过添加补缩浇道设计了新的工艺方案,模拟结果表明,采用8根补缩浇道的方案可消除缩松和缩孔缺陷。采用该优化方案,进行了机匣试验件实际浇注,获得了冶金质量良好的铸件。

In this work,numerical simulations were performed on the pouring process,temperature fields and the fraction of solid phase during the investment casting of experimental cartridge receiver made of 800℃K439B weldable superalloy,by using ProCAST software based on the macro-and microscale couple model of shrinkages and porosity developed according to Darcy law.It is found that shrinkage and porosity are formed at the bottom of casting which has thin wall due to the existence of isolation liquid phase area.New technologies were further designed by adding feeding sprues.The simulation results show that the shrinkages and porosity can be effectively eliminated after adding 8 feeding sprues.Experimental cartridge receiver with good metallurgical quality is successfully produced by the optimized technology.