Two kinds of argon shroud protection devices with two different basic structures were designed and investigated. Industrial experiments and numerical simulations were used to examine the protection effect, and the mec...Two kinds of argon shroud protection devices with two different basic structures were designed and investigated. Industrial experiments and numerical simulations were used to examine the protection effect, and the mechanism of air entrapment during the casting of steel ingots was analyzed. The influence of the structure of the argon shroud protection device on the protection effect was investigated. An argon shroud protection device mounted to the nozzle holder on the bottom of the ladle does not provide a good protection effect because air can easily flow into the teeming system and cause reoxidation of molten steel during teeming. By contrast, an argon shroud protection device seated on the top of the central trumpet provides an excellent protection effect, where air has little chance of flowing into the teeming system during casting. The feasibilities of the argon shroud protection devices are discussed.展开更多
Slag carry-over during the draining of molten steel from a teeming ladle is numerically studied here. Two-phase isothermal transient 3D Computational Fluid Dynamics simulations were employed to simulate the draining p...Slag carry-over during the draining of molten steel from a teeming ladle is numerically studied here. Two-phase isothermal transient 3D Computational Fluid Dynamics simulations were employed to simulate the draining process. Two nozzle diameters, two nozzle positions and three slag heights were considered. From mass balances, the slag carry-over in terms of mass flow rate was obtained for each of the above variables. Besides, the draining times of the teeming ladle were estimated from theoretical considerations and CDF simulations, and compared.展开更多
In this paper, the three dimensional flow field in the billet mold has been studied by simple numerical method.The influence caused by teeming deviation.from the mold center has been discussed.
Steel teeming time is a very important parameter in the new slide gate system with electromagnetic induction （called electromagnetic steel teeming system）, and how to shorten this time is a key to realize applicatio...Steel teeming time is a very important parameter in the new slide gate system with electromagnetic induction （called electromagnetic steel teeming system）, and how to shorten this time is a key to realize application of the new system in continuous casting. The effects of power parameters, coil position, nozzle material and other factors on the steel teeming time were investigated by a self-designed electromagnetic steel teeming system in detail. The experimental results show that the relationship between power and steel teeming time is nonlinear. The coil position has great in- fluence on steel teeming time. And the upper nozzle with high permeability can reduce the teeming time. In addition, the steel teeming time becomes minimum when the size of the spherical cast iron particles is 2.0 ram. This research can provide technical references for the industrial application of the new electromagnetic steel teeming system.展开更多
At the late stage of continuous casting（CC）ladle teeming,sink vortex can suck the liquid slag into tundish,and cause negative influences on the cleanliness of molten steel.To address this issue,a twophase fluid mech...At the late stage of continuous casting（CC）ladle teeming,sink vortex can suck the liquid slag into tundish,and cause negative influences on the cleanliness of molten steel.To address this issue,a twophase fluid mechanical modeling method for ladle teeming was proposed.Firstly,a dynamic model for vortex suction process was built,and the profiles of vortex flow field were acquired.Then,based on the level set method（LSM）,a two-phase 3Dinterface coupling model for slag entrapment was built.Finally,in combination with high-order essentially non-oscillatory（ENO）and total variation diminishing（TVD）methods,a LSM-based numerical solution method was proposed to obtain the 3Dcoupling evolution regularities in vortex suction process.Numerical results show that the vortex with higher kinetic energy can form an expanded sandglass-shape region with larger slag fraction and lower rotating velocity;there is a pressure oscillation phenomenon at the vortex penetration state,which is caused by the energy shock of two-phase vortex penetration coupling.展开更多
An innovative process of clad teeming was proposed to prepare slab ingot,which featured a built-in cold core to inhibit solidification defects.A 20-kg clad ingot was prepared in the experiment,using a volume ratio of ...An innovative process of clad teeming was proposed to prepare slab ingot,which featured a built-in cold core to inhibit solidification defects.A 20-kg clad ingot was prepared in the experiment,using a volume ratio of solid core to molten steel of 1:13 and a preheating temperature of cold core of 573 K.Solidification microstructures of the clad ingot were analyzed by comparing with a reference ingot without cold core.Interfacial morphologies and mechanical properties of the clad ingot were studied before and after hot rolling.The effect of cold core on heat transfer and nucleation during the solidification in clad ingot was analyzed.Results show that the solidification microstructures in the clad ingot are refined and homogenized obviously.The grain size in the center of the reference ingot is 2–3 times greater than that of clad ingot,and there is almost no columnar grain in the clad ingot.The interfacial shear strength reaches 318 MPa,which shows excellent metallurgical bonding at the interface of cold core and molten steel.Tiny defects at the interface are eliminated,and interfacial shear strength reaches 426 MPa after hot rolling with a 68.4%total reduction ratio.The experiment and analysis of this process are expected to provide a new idea to prepare large ingots with refinement and homogeneity at a low cost.展开更多
In the electromagnetic induction-controlled automated steel teeming(EICAST)technology of ladle,the height and location of the blocking layer are critical factors to determine the structure size and installation locati...In the electromagnetic induction-controlled automated steel teeming(EICAST)technology of ladle,the height and location of the blocking layer are critical factors to determine the structure size and installation location of induction coil.And,they are also the key parameters affecting the successful implementation of this new technology.In this paper,the influence of the liquid steel temperature,the holding time and the alloy composition on the height and location of the blocking layer were studied by numerical simulation.The simulation results were verified by 40 t ladle industrial experiments.Moreover,the regulation approach of the blocking layer was determined,and the determination process of coil size and its installation location were also analyzed.The results show that the location of the blocking layer moves down with the increase in the liquid steel temperature and the holding time.The height of the blocking layer decreases with the increase in the liquid steel temperature;however,it increases with the increase in the holding time.The height and location of the blocking layer can be largely adjusted by changing the alloy composition of filling particles in the upper nozzle.When the liquid steel temperature is 1550℃,the holding time is 180 min and the alloy composition is confirmed,the melting layer height is 120 mm,and the blocking layer height is 129 mm,which are beneficial to design and installation of induction coil.These results are very important for the industrial implementation of the EICAST technology.展开更多
Feeling the pressure of the U.S.second round of quantitative easing,the Chinese market is again plagued by excess liquidity.Consumer prices are running high and property prices have
基金supported by the National Natural Science Foundation of China(Grant No.51404018)the State Key Laboratory of Advanced Metallurgy Foundation(No.41614014)
文摘Two kinds of argon shroud protection devices with two different basic structures were designed and investigated. Industrial experiments and numerical simulations were used to examine the protection effect, and the mechanism of air entrapment during the casting of steel ingots was analyzed. The influence of the structure of the argon shroud protection device on the protection effect was investigated. An argon shroud protection device mounted to the nozzle holder on the bottom of the ladle does not provide a good protection effect because air can easily flow into the teeming system and cause reoxidation of molten steel during teeming. By contrast, an argon shroud protection device seated on the top of the central trumpet provides an excellent protection effect, where air has little chance of flowing into the teeming system during casting. The feasibilities of the argon shroud protection devices are discussed.
文摘Slag carry-over during the draining of molten steel from a teeming ladle is numerically studied here. Two-phase isothermal transient 3D Computational Fluid Dynamics simulations were employed to simulate the draining process. Two nozzle diameters, two nozzle positions and three slag heights were considered. From mass balances, the slag carry-over in terms of mass flow rate was obtained for each of the above variables. Besides, the draining times of the teeming ladle were estimated from theoretical considerations and CDF simulations, and compared.
文摘In this paper, the three dimensional flow field in the billet mold has been studied by simple numerical method.The influence caused by teeming deviation.from the mold center has been discussed.
基金Sponsored by Science and Techonlogy Program of Liaoning Province of China(2008221015)
文摘Steel teeming time is a very important parameter in the new slide gate system with electromagnetic induction （called electromagnetic steel teeming system）, and how to shorten this time is a key to realize application of the new system in continuous casting. The effects of power parameters, coil position, nozzle material and other factors on the steel teeming time were investigated by a self-designed electromagnetic steel teeming system in detail. The experimental results show that the relationship between power and steel teeming time is nonlinear. The coil position has great in- fluence on steel teeming time. And the upper nozzle with high permeability can reduce the teeming time. In addition, the steel teeming time becomes minimum when the size of the spherical cast iron particles is 2.0 ram. This research can provide technical references for the industrial application of the new electromagnetic steel teeming system.
基金supported by NSFC-Zhejiang Joint Fund for the Integration of Industrialization and Informatization(U1509212)National Natural Science Foundation of China(51375446)Zhejiang Provincial Natural Science Foundation for Distinguished Young Scientists(LR16E050001)
文摘At the late stage of continuous casting（CC）ladle teeming,sink vortex can suck the liquid slag into tundish,and cause negative influences on the cleanliness of molten steel.To address this issue,a twophase fluid mechanical modeling method for ladle teeming was proposed.Firstly,a dynamic model for vortex suction process was built,and the profiles of vortex flow field were acquired.Then,based on the level set method（LSM）,a two-phase 3Dinterface coupling model for slag entrapment was built.Finally,in combination with high-order essentially non-oscillatory（ENO）and total variation diminishing（TVD）methods,a LSM-based numerical solution method was proposed to obtain the 3Dcoupling evolution regularities in vortex suction process.Numerical results show that the vortex with higher kinetic energy can form an expanded sandglass-shape region with larger slag fraction and lower rotating velocity;there is a pressure oscillation phenomenon at the vortex penetration state,which is caused by the energy shock of two-phase vortex penetration coupling.
基金This project was supported by National Natural Science Foundation of China(Grant Nos.51974156 and 51974153)Key Laboratory of Sea Industry Steel Ansteel(Grant No.SKLMEA-USTL-201702).
文摘An innovative process of clad teeming was proposed to prepare slab ingot,which featured a built-in cold core to inhibit solidification defects.A 20-kg clad ingot was prepared in the experiment,using a volume ratio of solid core to molten steel of 1:13 and a preheating temperature of cold core of 573 K.Solidification microstructures of the clad ingot were analyzed by comparing with a reference ingot without cold core.Interfacial morphologies and mechanical properties of the clad ingot were studied before and after hot rolling.The effect of cold core on heat transfer and nucleation during the solidification in clad ingot was analyzed.Results show that the solidification microstructures in the clad ingot are refined and homogenized obviously.The grain size in the center of the reference ingot is 2–3 times greater than that of clad ingot,and there is almost no columnar grain in the clad ingot.The interfacial shear strength reaches 318 MPa,which shows excellent metallurgical bonding at the interface of cold core and molten steel.Tiny defects at the interface are eliminated,and interfacial shear strength reaches 426 MPa after hot rolling with a 68.4%total reduction ratio.The experiment and analysis of this process are expected to provide a new idea to prepare large ingots with refinement and homogeneity at a low cost.
基金financially supported by the National Natural Science Foundation of China(Grant No.U1560207)the Liaoning Innovative Research Team in University(Grant No.LT2017011)
文摘In the electromagnetic induction-controlled automated steel teeming(EICAST)technology of ladle,the height and location of the blocking layer are critical factors to determine the structure size and installation location of induction coil.And,they are also the key parameters affecting the successful implementation of this new technology.In this paper,the influence of the liquid steel temperature,the holding time and the alloy composition on the height and location of the blocking layer were studied by numerical simulation.The simulation results were verified by 40 t ladle industrial experiments.Moreover,the regulation approach of the blocking layer was determined,and the determination process of coil size and its installation location were also analyzed.The results show that the location of the blocking layer moves down with the increase in the liquid steel temperature and the holding time.The height of the blocking layer decreases with the increase in the liquid steel temperature;however,it increases with the increase in the holding time.The height and location of the blocking layer can be largely adjusted by changing the alloy composition of filling particles in the upper nozzle.When the liquid steel temperature is 1550℃,the holding time is 180 min and the alloy composition is confirmed,the melting layer height is 120 mm,and the blocking layer height is 129 mm,which are beneficial to design and installation of induction coil.These results are very important for the industrial implementation of the EICAST technology.
文摘Feeling the pressure of the U.S.second round of quantitative easing,the Chinese market is again plagued by excess liquidity.Consumer prices are running high and property prices have
