钛合金阀体件“一模多件”铸造工艺优化设计

Optimization Design of"One Mold Multi-parts"Casting Process for Titanium Alloy Valve Body

目的对钛合金阀体件“一模多件”铸造工艺进行优化研究,达到降低成本、保证铸件产品质量的目的。方法以ZTA2钛合金阀体件为研究对象,基于零件壁厚范围较宽的结构特点、零件的技术要求与生产实际现状,结合经验分析及数值模拟仿真技术进行铸造工艺设计。结果确定分型面和浇冒口的设计,在热节点及孤立液相区域设置补缩冒口,通过数值模拟对铸件模拟结果的缩孔缩松情况进行分析,优化冒口的设计,增加补缩通道,最终确定合理的“一模多件”开放式浇注系统。对于“一模多件”铸造工艺,通过合理设计浇注系统,可以有效保证浇注过程中各层铸件的平稳浇注。浇注系统宜采用开放式的浇注系统,直浇道、横浇道、内浇口的截面积比例为1∶2∶4。结论采用机加工石墨型铸造,在真空凝壳炉完成熔炼,在浇注温度为1770℃、模壳预热温度为200℃的情况下,采用重力浇注的形式在真空凝壳炉中铸造生产出钛合金阀体件,所获得的铸件无铸造缺陷,其成分和力学性能均满足质量要求。研究结果表明,在铸造过程中使用数值模拟技术可以优化铸造工艺设计,缩短产品试制周期,大大提高生产效率。

The work aims to optimize the“one mold multi-parts”casting process of titanium alloy valve body,so as to reduce the cost and ensure the quality of castings.ZTA2 titanium alloy valve body was taken as the research object.Based on the structural characteristics of valve with a wide range of thickness,technical requirements and actual production,the casting process was designed combined with empirical analysis and numerical simulation technology.Parting surface and sprue were determined,and filler sprue was set in the hot node and isolated liquid phase area.The design of sprue was optimized and the filler channel was increased after numerical analysis on the shrinkage cavity and porosity in the casting simulation results.Ultimately,a reasonable“one mold multi-parts”open casting system was determined.In this casting system,stable pouring of each layer of castings could be effectively ensured through the reasonable design of the pouring system.An open pouring system with a cross-sectional area ratio of sprue:runner:ingate as 1:2:4 should be adopted.Titanium alloy valve can be produced by gravity casting method with a machined graphite mold and a vacuum condensing furnace under the condition of pouring temperature at 1770℃and preheating temperature of mold shell at 200℃.Castings obtained in this study barely have defects and the composition and mechanical properties meet the quality requirements.The results show that the numerical simulation technology used in the casting process can optimize casting process design,shorten trial production cycle and greatly improve the efficiency.