浇注系统对离心铸造TiAl合金杆形件缩孔缺陷的影响  

Effect of pouring system on shrinkage porosity of TiAl alloy rod castings by centrifugal casting

作　　者：胡海涛[1] 张熹雯[1] 朱春雷[1] 李胜[1] 张继[1] HU Haitao;ZHANG Xiwen;ZHU Chunlei;LI Sheng;ZHANG Ji(Beijing Key Laboratory of Advanced High Temperature Materials,Central Iron and Steel Research Institute,Beijing 100081,China)

机构地区：[1]钢铁研究总院高温合金新材料北京市重点实验室

出　　处：《航空材料学报》2019年第3期53-61,共9页Journal of Aeronautical Materials

摘　　要：采用数值模拟方法研究杆形件直径和补缩冒口结构对离心铸造TiAl合金杆形件缩孔缺陷的影响,并根据充型和凝固温度场对影响的原因进行分析。结果表明:杆形件直径由16mm增加到20mm,并进一步设计成入口处直径20mm、远端直径16mm的锥形,杆形件补缩通道被阻塞的趋势逐渐减小,用于补缩的金属液温度提高,凝固时间逐渐增长,因而补缩效果提高,杆形件缩孔缺陷水平逐渐降低;基于杆形件的锥形设计,相比无补缩冒口的杆形件,增加环形补缩冒口,充型时金属液顺序凝固趋势减弱,凝固时用于补缩的金属液温度降低,凝固时间缩短,因而补缩效果降低,缩孔缺陷水平略有提高;增加锥形补缩冒口,充型时金属液顺序凝固趋势增强,凝固时用于补缩的金属液温度提高,凝固时间增长,因而补缩效果提高,缩孔缺陷水平降低。优选最佳设计进行了浇注实验,杆形件剖面最大缺陷孔隙率平均值与模拟实验的结果基本一致。Numerical simulation was used to study the influence of the diameter and riser structure of rod castings on the shrinkage porosity of TiAl alloy rod castings by centrifugal casting. The reasons for the influence were analyzed according to the filling and solidification temperature fields. The results indicate that the diameter of rod castings is increased from 16 mm to 20 mm, the diameter of the entrance area is further designed into 20 mm, and the diameter of the distal end is 16 mm, the tendency for blocking the rod casting filler channel is gradually reduced, the temperature of the molten metal for feeding is increased, and the solidification time is gradually increased. Thus the feeding effect is increased, and the level of shrinkage porosity is gradually reduced. Based on the conical design of rod castings, compared with the rod castings without risers, the added ring-shaped riser causes the sequential solidification tendency of the molten metal during filling weakened, the temperature of the molten metal for feeding during solidification decreased, and the solidification time shortened. Thus the feeding effect is decreased, and the level of shrinkage porosity is slightly increased. With adding the cone-shaped riser, the sequential solidification tendency of the molten metal during filling is enhanced, the temperature of the molten metal for feeding during solidification is increased, and the solidification time is increased. Thus the feeding effect is improved, and the level of shrinkage porosity is decreased. The pouring test of the casting is carried out with the best design. The average value of the maximum shrinkage porosity of the section of rod castings is basically the same as that of the simulation test.

关 键 词：TIAL合金 离心铸造 杆形件直径 补缩冒口结构 缩孔缺陷 数值模拟 

分 类 号：TG244.4[金属学及工艺—铸造]