Abstract: Two advanced technologies of electromagnetic confinement to process the Fe- and Ni-base alloys for castings and ingots with shaped cross section were introduced. Based on systematically investigation on the distribution behavior of magnetic and temperature field and their coupling effect, the containerless electromagnetic shaping of stainless steel and superalloy test samples were successfully realized by means of an specially designed vacuum apparatus with dual induction coils and dual frequencies and by using of a tailor-made crystallizator, the near-shape superalloy turbine blade castings with directionally solidified microstructure by electromagnetic soft-contact confinement technology were also obtained. The dynamic stability and profile behavior of melt and temperature gradient during electromagnetic confinement were presented, the results by quasi-3D calculation simulating the electromagnetic shaping process in consistent with experiments were also given.
Electromagnetic confinement and solidification control of Ni-base superalloys under vacuum
Abstract:
Two advanced technologies of electromagnetic confinement to process the Fe- and Ni-base alloys for castings and ingots with shaped cross section were introduced. Based on systematically investigation on the distribution behavior of magnetic and temperature field and their coupling effect, the containerless electromagnetic shaping of stainless steel and superalloy test samples were successfully realized by means of an specially designed vacuum apparatus with dual induction coils and dual frequencies and by using of a tailor-made crystallizator, the near-shape superalloy turbine blade castings with directionally solidified microstructure by electromagnetic soft-contact confinement technology were also obtained. The dynamic stability and profile behavior of melt and temperature gradient during electromagnetic confinement were presented, the results by quasi-3D calculation simulating the electromagnetic shaping process in consistent with experiments were also given.
Fig.4 Effect of frequency and ratio of magnetic flux density on ratio of heat and force (Q/pm) 1—a=4 mm, f1=300 kHz, B1=0.04 T, B2=0.04 T, μσ=5.03 H·Ω-1·m-2;2—a=4 mm, f1=300 kHz, f2=10 kHz, μσ=5.03 H·Ω-1·m-2
Fig.5 Computed electromagnetic pressure for electromagnetic confining of elliptical (a) and crescent moon (b) cross section shapes1—Electromagnetic pressure demanded by confining 60 mm height of aluminum melt;2—Electromagnetic pressure demanded by confining 40 mm height of aluminum melt.
图6 无接触电磁成形过程中试样中心沿轴向的温度梯度分布特征
Fig.6 Temperature gradient distribution in center of test sample under electromagnetic containerless confinement process