With the aid of ANSYS software, the effect of different mould external part materials on magnetic flux density and electromagnetic body force in the liquid aluminum was investigated. Calculated results showed that mag...With the aid of ANSYS software, the effect of different mould external part materials on magnetic flux density and electromagnetic body force in the liquid aluminum was investigated. Calculated results showed that magnetic flux density and electromagnetic body force in the aluminum melt are greatly increased when the external part of mould is made from A3 steel. A low-frequency electromagnetic casting 6063 aluminum alloy experiment was conducted in the laboratory with the current value of 120 A and frequency value of 15 Hz. The experiment showed that the microstructure and surface quality of ingots with mould outer part made from A3 steel under low-frequency electromagnetic field are better than that of ingots with mould outer part made from austenitic stainless steel. The surface of the ingots with mould outer part made from A3 steel is smooth and free from exudations and cold shut defects. The as-cast microstructure consists of fine, uniformly distributed equiaxed grains.展开更多
The electromagnetic dam (EMD) in twin-roll strip caster was simulated with FEM. The results show that the direction and magnitude of Lorentz force distributing in the EMD changed in a period. The negative part is abou...The electromagnetic dam (EMD) in twin-roll strip caster was simulated with FEM. The results show that the direction and magnitude of Lorentz force distributing in the EMD changed in a period. The negative part is about 30% of the positive part, and the acting time of the negative force is about 40% of a period. In order to prevent the liquid steel from leaking efficiently, the distance between two poles should be the same from the top to the bottom of the EMD, otherwise the magnetic induction will be very small at the top and large at the bottom.展开更多
The effect of refined precipitations and dispersed phases on the toughness of SS400 steel was investigated by rapid tempering with thermomechanical simulation tester, and the electromagnetic induction rapid tempering ...The effect of refined precipitations and dispersed phases on the toughness of SS400 steel was investigated by rapid tempering with thermomechanical simulation tester, and the electromagnetic induction rapid tempering process was simulated. The conventional tempering and rapid tempering process were proceeded respectively, and both samples were quenched in 10% of agitated iced brine. The tempering temperatures were designed as 560, 620 and 680 ℃, respectively. Rapid tempering specimens were heated at a heating rate of 20 ℃/s, and all samples of these three tempering temperatures were maintained 30, 40 and 50 s with the Gleeble1500-D tester, respectively. The impact test at -40 ℃ were carried out on a Charpy impact machine (CBD-300) with a maximum measurement range of 300 J and the microstructures were analyzed in detail using optical microscope (OM) and scanning electron microscope (SEM). The experiment results show that the upper bainite, martensite and small amount of austenite were obtained in the rapidly quenched samples. In comparison to the conventional process, the matrix microstructure was changed from the larger size and bulk ferrite to the refined banding structure, and the cementites were obviously refined and precipitated inside the grains and along the grain boundaries. The cryogenic impact test implies that the maximum values of impact toughness with holding time of 30 or 50 s are achieved at tempering temperature of 620 ℃. Furthermore, a favorite value of impact toughness with holding time of 40 s is available.展开更多
基金The project (G199906490501) was supported by the National Key Fundamental Research and Development Program of China
文摘With the aid of ANSYS software, the effect of different mould external part materials on magnetic flux density and electromagnetic body force in the liquid aluminum was investigated. Calculated results showed that magnetic flux density and electromagnetic body force in the aluminum melt are greatly increased when the external part of mould is made from A3 steel. A low-frequency electromagnetic casting 6063 aluminum alloy experiment was conducted in the laboratory with the current value of 120 A and frequency value of 15 Hz. The experiment showed that the microstructure and surface quality of ingots with mould outer part made from A3 steel under low-frequency electromagnetic field are better than that of ingots with mould outer part made from austenitic stainless steel. The surface of the ingots with mould outer part made from A3 steel is smooth and free from exudations and cold shut defects. The as-cast microstructure consists of fine, uniformly distributed equiaxed grains.
文摘The electromagnetic dam (EMD) in twin-roll strip caster was simulated with FEM. The results show that the direction and magnitude of Lorentz force distributing in the EMD changed in a period. The negative part is about 30% of the positive part, and the acting time of the negative force is about 40% of a period. In order to prevent the liquid steel from leaking efficiently, the distance between two poles should be the same from the top to the bottom of the EMD, otherwise the magnetic induction will be very small at the top and large at the bottom.
基金Sponsored by Natural Science Foundation of Inner Mongolia Autonomous Region of China (Grant No.2009MS0811)
文摘The effect of refined precipitations and dispersed phases on the toughness of SS400 steel was investigated by rapid tempering with thermomechanical simulation tester, and the electromagnetic induction rapid tempering process was simulated. The conventional tempering and rapid tempering process were proceeded respectively, and both samples were quenched in 10% of agitated iced brine. The tempering temperatures were designed as 560, 620 and 680 ℃, respectively. Rapid tempering specimens were heated at a heating rate of 20 ℃/s, and all samples of these three tempering temperatures were maintained 30, 40 and 50 s with the Gleeble1500-D tester, respectively. The impact test at -40 ℃ were carried out on a Charpy impact machine (CBD-300) with a maximum measurement range of 300 J and the microstructures were analyzed in detail using optical microscope (OM) and scanning electron microscope (SEM). The experiment results show that the upper bainite, martensite and small amount of austenite were obtained in the rapidly quenched samples. In comparison to the conventional process, the matrix microstructure was changed from the larger size and bulk ferrite to the refined banding structure, and the cementites were obviously refined and precipitated inside the grains and along the grain boundaries. The cryogenic impact test implies that the maximum values of impact toughness with holding time of 30 or 50 s are achieved at tempering temperature of 620 ℃. Furthermore, a favorite value of impact toughness with holding time of 40 s is available.
