浇注系统对离心铸造TiAl合金杆形件缩孔缺陷的影响
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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16 mm增加到20 mm,并进一步设计成入口处直径20 mm、远端直径16 mm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.
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.
引文
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[7]吴士平,郭景杰,苏彦庆,等.TiAl基合金排气阀离心铸造充型过程数值模拟的试验验证[J].铸造,2001,50(9):560-563.(WU S P,GUO J J,SU Y Q,et al.Verification of a numerical simulation of the mold filling processes on centrifugal casting of exhausting valves of TiAl based alloys[J].Foundry,2001,50(9):560-563.)
[8]苏彦庆,刘畅,毕维升,等.TiAl基合金杆形件铸造缺陷和铸造方法的关系[J].特种铸造及有色合金,2002,5:11-14.(SU Y Q,LIU C,BI W S,et al.Influence of casting processes on shrinkage distribution in TiAl based alloy shaft castings[J].Special Casting and Nonferrous Alloys,2002,5:11-14.)
[9]吴士平,郭景杰,贾均.TiAl基合金排气阀立式离心铸造充型及凝固过程数值模拟[J].金属学报,2004,40(3):326-330.(WU S P,GUO J J,JIA J.Numerical simulation of mold filling and solidification of TiAl base alloy exhaust valve in vertical centrifugal casting process[J].Acta Metallurgica Sinica,2004,40(3):326-330.)
[10]LIU K,MA Y C,GAO M,et al.Single step centrifugal casting TiAl automotive valves[J].Intermetallics,2005,13:925-928.
[11]SHENG W B.Filling and solidification of TiAl melt in centrifugal field[J].Transactions of Nonferrous Metals Society of China,2006,16(Suppl 2):719-722.
[12]FU P X,KANG X H,MA Y C,et al.Centrifugal casting of TiAl exhaust valves[J].Intermetallics,2008,16:130-138.
[13]马颖澈,熊超,陈波,等.离心铸造Ti47Al2Nb1Cr1W0.2Si合金汽车气阀的铸造特性[J].稀有金属材料与工程,2012,41(7):1293-1297.(MA Y C,XIONG C,CHEN B,et al.Cast characteristics of Ti47Al2Nb1Cr1W0.2Si alloy car valves by centrifugal casting[J].Rare Metal Materials and Engineering,2012,41(7):1293-1297.)
[14]李日,马军贤,崔启玉.铸造工艺仿真ProCAST从入门到精通[M].北京:中国水利水电出版社,2010.(LI R,MA J X,CUI Q Y.Casting process simulation ProCAST from getting started to proficient[M].Beijing:China Water and Power Press,2010.)
[15]SUNG S Y,KIM Y J.Modeling of titanium aluminides turbo-charger casting[J].Intermetallics,2007,15:468-474.
[16]潘利文,高永,高文理,等.基于ProCAST的TiAl叶片缩孔缩松预测及工艺优化[J].特种铸造及有色合金,2010,30(6):504-508.(PAN L W,GAO Y,GAO W L,et al.Prediction of shrinkage porosity(hole)in TiAl based alloy blade and its processing optimization based on the ProCAST[J].Special Casting and Nonferrous Alloys,2010,30(6):504-508.)
[17]XIONG C,MA Y C,CHEN B,et al.Modeling of filling and solidification process for TiAl exhaust valves[J].Acta Metallurgica Sinica,2013,26(1):33-48.
[18]LU D A.Thermophysical properties necessary for advanced casting simulation[J].International Journal of Thermophysics,2002,29(5):1131-1146.
[2]盛文斌,李东,杨锐,等.金属型铸造Ti-48%Al-2%Cr-2%Nb合金汽车排气阀的研制[J].铸造,2001,50(3):129-133.(SHENG W B,LI D,YANG R,et al.Research on Ti-48%Al-2%Cr-2%Nb automobile exhaust valve cast by centrifugal casting process in permanent mold[J].Foundry,2001,50(3):129-133.)
[3]李胜,姜明智,王新英,等.TiAl合金反重力铸造用陶瓷型壳的调整[J].热加工工艺,2011,40(23):27-29.(LI S,JIANG M Z,WANG X Y,et al.Modification of ceramic mould for counter-gravity casting of TiAl alloy[J].Hot Working Technology,2011,40(23):27-29.)
[4]陈玉勇,陈艳飞,田竟,等.TiAl基合金熔模精密铸造技术的发展现状[J].稀有金属材料与工程,2009,38(3):554-558.(CHEN Y Y,CHEN Y F,TIAN J,et al.Development and research status of investment casting TiAl-based alloys[J].Rare Metal Materials and Engineering,2009,38(3):554-558.)
[5]盛文斌,郭景杰,苏彦庆,等.TiAl基合金离心铸造过程中的层流临界值分析[J].航空材料学报,1999,19(3):1-6.(SHENG W B,GUO J J,SU Y Q,et al.Analysis of laminar flow critical value for TiAl based alloy during centrifugal casting process[J].Journal of Aeronautical Materials,1999,19(3):1-6.)
[6]盛文斌,郭景杰,苏彦庆,等.TiAl基合金排气阀金属型离心铸造过程内部缺陷分析[J].航空材料学报,2000,20(2):40-45.(SHENG W B,GUO J J,SU Y Q,et al.Analysis on inner defects in TiAl based alloy exhaust valve during the centrifugal foundry process in permanent mold[J].Journal of Aeronautical Materials,2000,20(2):40-45.)
[7]吴士平,郭景杰,苏彦庆,等.TiAl基合金排气阀离心铸造充型过程数值模拟的试验验证[J].铸造,2001,50(9):560-563.(WU S P,GUO J J,SU Y Q,et al.Verification of a numerical simulation of the mold filling processes on centrifugal casting of exhausting valves of TiAl based alloys[J].Foundry,2001,50(9):560-563.)
[8]苏彦庆,刘畅,毕维升,等.TiAl基合金杆形件铸造缺陷和铸造方法的关系[J].特种铸造及有色合金,2002,5:11-14.(SU Y Q,LIU C,BI W S,et al.Influence of casting processes on shrinkage distribution in TiAl based alloy shaft castings[J].Special Casting and Nonferrous Alloys,2002,5:11-14.)
[9]吴士平,郭景杰,贾均.TiAl基合金排气阀立式离心铸造充型及凝固过程数值模拟[J].金属学报,2004,40(3):326-330.(WU S P,GUO J J,JIA J.Numerical simulation of mold filling and solidification of TiAl base alloy exhaust valve in vertical centrifugal casting process[J].Acta Metallurgica Sinica,2004,40(3):326-330.)
[10]LIU K,MA Y C,GAO M,et al.Single step centrifugal casting TiAl automotive valves[J].Intermetallics,2005,13:925-928.
[11]SHENG W B.Filling and solidification of TiAl melt in centrifugal field[J].Transactions of Nonferrous Metals Society of China,2006,16(Suppl 2):719-722.
[12]FU P X,KANG X H,MA Y C,et al.Centrifugal casting of TiAl exhaust valves[J].Intermetallics,2008,16:130-138.
[13]马颖澈,熊超,陈波,等.离心铸造Ti47Al2Nb1Cr1W0.2Si合金汽车气阀的铸造特性[J].稀有金属材料与工程,2012,41(7):1293-1297.(MA Y C,XIONG C,CHEN B,et al.Cast characteristics of Ti47Al2Nb1Cr1W0.2Si alloy car valves by centrifugal casting[J].Rare Metal Materials and Engineering,2012,41(7):1293-1297.)
[14]李日,马军贤,崔启玉.铸造工艺仿真ProCAST从入门到精通[M].北京:中国水利水电出版社,2010.(LI R,MA J X,CUI Q Y.Casting process simulation ProCAST from getting started to proficient[M].Beijing:China Water and Power Press,2010.)
[15]SUNG S Y,KIM Y J.Modeling of titanium aluminides turbo-charger casting[J].Intermetallics,2007,15:468-474.
[16]潘利文,高永,高文理,等.基于ProCAST的TiAl叶片缩孔缩松预测及工艺优化[J].特种铸造及有色合金,2010,30(6):504-508.(PAN L W,GAO Y,GAO W L,et al.Prediction of shrinkage porosity(hole)in TiAl based alloy blade and its processing optimization based on the ProCAST[J].Special Casting and Nonferrous Alloys,2010,30(6):504-508.)
[17]XIONG C,MA Y C,CHEN B,et al.Modeling of filling and solidification process for TiAl exhaust valves[J].Acta Metallurgica Sinica,2013,26(1):33-48.
[18]LU D A.Thermophysical properties necessary for advanced casting simulation[J].International Journal of Thermophysics,2002,29(5):1131-1146.