Mg-Y4-Nd2-Gd1系高性能耐热镁合金铸造工艺——用于复杂薄壁舱体

Casting Process of Mg-Y4-Nd2-Gd1 Series High-Performance HeatResistant Magnesium Alloy——Applied for Complex Thin-Walled Cabin

针对航空航天装备轻量化需求,基于某过渡舱壳体铸件研制,进行Mg-Y4-Nd2-Gd1系高性能耐热镁合金铸造工艺研究。开展了熔炼、铸造、热处理等工艺技术方案分析,提出收缩率等参数的设计原则,进行铸造成型模拟。根据模拟结果,分析、明确铸件缺陷成因,提出将浇注系统改为3°锥形、适当提高充型速度等优化措施;提出了优化指标,进行二次模拟,其结果表明优化措施及铸造方案改进效果良好。将优化方案应用于生产验证,铸件合格率达到75%,实现了以下目标:1)常温下抗拉强度达到300 MPa,延伸率达到3%;2)250℃下抗拉强度达到230 MPa,延伸率达到5%。为高性能耐热镁合金铸件批量化生产奠定了基础。

According to the lightweight requirements of aerospace equipment,the casting process of Mg-Y4-Nd2-Gd1 series high-performance heat-resistant magnesium alloy is studied based on the development of a transition cabin shell casting.Technological schemes including melting,casting and heat treatment are analyzed,the design principles of parameters such as shrinkage are put forward,and the casting simulation is carried out.According to the simulation results,the causes of casting defects are analyzed and identified,and the optimization measures such as changing the gating system to 30 taper and appropriately increasing the filling speed are put forward.The optimized indexes are proposed,the secondary simulation is carried out,showing that the optimization measures and casting schemes have a good improvement effect.The optimized scheme is applied to production verification,and the qualified rate of castings reached 75%,achieving the following goals:1)The tensile strength at room temperature reached 300 MPa and the elongation reached 3%;2)At 250℃,the tensile strength reaches 230 MPa and the elongation reaches 5%.It lays a foundation for batch production of highperformance heat-resistant magnesium alloy castings.