In this work, some important factors such as ceramic shell strength, heat preservation temperature, standing time and withdrawal rate, which influence the formability of directionally solidified large-size blades of h...In this work, some important factors such as ceramic shell strength, heat preservation temperature, standing time and withdrawal rate, which influence the formability of directionally solidified large-size blades of heavy-duty gas turbine with the liquid metal cooling(LMC) process, were studied through the method of microstructure analysis combining. The results show that the ceramic shell with medium strength(the high temperature flexural strength is 8 MPa, the flexural strength after thermal shock resistance is 12 MPa and the residual flexural strength is 20 MPa) can prevent the rupture and runout of the blade. The appropriate temperature(1,520 ℃ for upper region and 1,500 ℃ for lower region) of the heating furnace can eliminate the wide-angle grain boundary, the deviation of grain and the run-out caused by the shell crack. The holding time after pouring(3-5 min) can promote the growth of competitive grains and avoid a great deviation of columnar grains along the crystal orientation <001>, resulting in a straight and uniform grain structure. In addition, to avoid the formation of wrinkles and to ensure a smooth blade surface, the withdrawal rate should be no greater than the growth rate of grain. It is also found that the dendritic space of the blade decreases with the rise of solidification rate, and increases with the enlarging distance between the solidification position and the chill plate.展开更多
高温合金由于其优异的综合高温性能被应用于航空发动机、燃气轮机等热端部件的制造,随着装备设计对材料服役温度要求的日益提高,对高温合金的综合性能要求越来越严苛,具有更加优异性能的改型合金不断诞生。以我国某新型重型燃气轮机大...高温合金由于其优异的综合高温性能被应用于航空发动机、燃气轮机等热端部件的制造,随着装备设计对材料服役温度要求的日益提高,对高温合金的综合性能要求越来越严苛,具有更加优异性能的改型合金不断诞生。以我国某新型重型燃气轮机大尺寸定向柱晶空心透平叶片用改型合金DZ411G为研究对象,借助相图计算软件JmatPro,通过热力学计算分析了C,Al,Ti,Cr,Ta等元素对主要合金相的开始析出温度、最大析出量、固液相线、γ/γ′错配度等的影响规律,为DZ411G合金化学成分优化、熔炼配入点设计及热处理工艺制定提供了依据。根据理论计算结果,设计了合理的配入点,并首次完成了2.5 t DZ411G母合金的工业化生产。展开更多
基金financially supported by the National Science and Technology Major Project of High-end CNC Machine Tools and Basic Manufacturing Equipment(No.2017ZX04014001)
文摘In this work, some important factors such as ceramic shell strength, heat preservation temperature, standing time and withdrawal rate, which influence the formability of directionally solidified large-size blades of heavy-duty gas turbine with the liquid metal cooling(LMC) process, were studied through the method of microstructure analysis combining. The results show that the ceramic shell with medium strength(the high temperature flexural strength is 8 MPa, the flexural strength after thermal shock resistance is 12 MPa and the residual flexural strength is 20 MPa) can prevent the rupture and runout of the blade. The appropriate temperature(1,520 ℃ for upper region and 1,500 ℃ for lower region) of the heating furnace can eliminate the wide-angle grain boundary, the deviation of grain and the run-out caused by the shell crack. The holding time after pouring(3-5 min) can promote the growth of competitive grains and avoid a great deviation of columnar grains along the crystal orientation <001>, resulting in a straight and uniform grain structure. In addition, to avoid the formation of wrinkles and to ensure a smooth blade surface, the withdrawal rate should be no greater than the growth rate of grain. It is also found that the dendritic space of the blade decreases with the rise of solidification rate, and increases with the enlarging distance between the solidification position and the chill plate.
文摘高温合金由于其优异的综合高温性能被应用于航空发动机、燃气轮机等热端部件的制造,随着装备设计对材料服役温度要求的日益提高,对高温合金的综合性能要求越来越严苛,具有更加优异性能的改型合金不断诞生。以我国某新型重型燃气轮机大尺寸定向柱晶空心透平叶片用改型合金DZ411G为研究对象,借助相图计算软件JmatPro,通过热力学计算分析了C,Al,Ti,Cr,Ta等元素对主要合金相的开始析出温度、最大析出量、固液相线、γ/γ′错配度等的影响规律,为DZ411G合金化学成分优化、熔炼配入点设计及热处理工艺制定提供了依据。根据理论计算结果,设计了合理的配入点,并首次完成了2.5 t DZ411G母合金的工业化生产。
