Papers by Keyword: Continuous Casting

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Authors: Mihály Réger, Balázs Verő, Árpád Szélig
Abstract: This paper deals with the characterization of solidification, cooling and expected properties of continuously cast slabs. Semi-empirical models based on theoretical consideration and on the results of heat transfer model are used for characterization of the following: surface and inner temperature distribution of the cast semis, liquid sump depth and shape, liquid motion intensity resulting in centerline segregation, parameters of the primary dendritic structure (primary and secondary dendritic spacings, columnar to equiaxed transition position, CET). This method provides an opportunity to make a realistic comparison between the solidification and final properties of semis with different chemical compositions as a function of applied casting technologies. The final goal of this research activity in the future is to define a comprehensive quality function for optimizing continuous casting technology.
Authors: Wei Chen, Bao Xiang Wang, Yu Zhu Zhang, Jin Hong Ma, Su Juan Yuan
Abstract: In this paper, a three-dimensional finite element model is developed to simulate and analyze the turbulent flow in the mould of billet continuous casting. The result shows that if the SEN is used in the continuous casting process, there exists a symmetrical stronger vortex in the middle of the mould and a weaker vortex above the nozzle. The casting speed, the depth and diameter of SEN all have significant effect on the fluid flow field and the turbulent kinetic energy on the meniscus, and then have effect on the billet quality. At the given conditions, the optimum set of parameters is: the casting speed 0.035 , the depth of the SEN 0.1 , the diameter of the SEN 0.025 . Online verifying of this model has been developed, which can be proved that it is very useful to control the steel quality and improve the productivity.
Authors: Qi Zhang, La Dao Yang
Abstract: A model of heat transfer and solidification of continuous cast has been established, including boundary conditions in the mold and spray zones. A finite difference method was used for the numerical simulation. The model calculates the shell thickness and temperature distributions of the slab real time. The importance effect of non-linear material properties of specific heat and thermal conductivity as well as phase changes during solidification is treated. The adequacy of model has been proved by industrial and experimental data. The model can be applied to solve some practical problems in continuous cast.
Authors: Qi Zhang, La Dao Yang, Heng Wen
Abstract: A two-dimensional (2-D) heat transfer and solidification model has been established and applied to calculate the temperature distribution and solid shell thickness profile of a continuous casting slab in a steel plant. A finite difference method was used for the numerical simulation. For thermal analysis, the 2-D slice unsteady-state heat conduction equation with enthalpy convention was used. Meanwhile, non-linear material properties of specific heat and thermal conductivity as well as phase changes during solidification were considered in the model. The temperature distribution and solid shell thickness calculated by mathematical model agree with those predicted by industrial and experimental measurements. The model could also be used to predict the optimum process parameters on casting speed, heat removal rates and the water distribution of secondary cooling zone.
Authors: Zuo Sheng Lei, Xiao Hua Yang, Ru Jun Wei, Qi Gao
Abstract: Liquid metal flow behavior in round strands continuous casting under intermittently reversing direction electromagnetic stirring was measured by ultrasonic Doppler velocity-meter in a physical simulation system in order to investigate the effects of time interval () of periodically reversed magnetic field on the spatial and temporal flow. The results show that under electromagnetic stirring with direction reserved magnetic field, theres a periodically change of the metal flow velocity and rotation direction with the periodically direction changing of the magnetic field. From both the experimental and mathematical model calculation results, it is found that when is nearly equal to the time required for the metal flow speeding to the maximum velocity from still and decreases to zero again, there is a critical value of the rate of dynamic pressure, which means the wash effect of the liquid metal flow. On this point, rate of dynamic pressure was proposed to be a criterion for optimization the processing of electromagnetic stirring.
Authors: Xin Jin, Ting Zhi Ren
Abstract: A new non-sinusoidal oscillation waveform which is shown by waveform distortional rate was advanced. The amplitude, oscillation frequency, waveform distortional rate and casting velocity were established for a computer model of the continuous casting process. The range of waveform distortional rate was ascertained. The choosing method of amplitude and oscillation frequency was given. These offered a theory basis to the application of the advanced technique. Industrial scale experiments showed the new type waveform is effective on improving the quality of continuous casting slab and reducing breakout.
Authors: Toshio Haga, Kazuya Akitsu, Shinji Kumai, Hisaki Watari
Abstract: Single roll caster to cast strip with sound free solidified surface was invented. A scraper was attached to the single roll caster to improve the free solidified surface. AA5182 and AA6022 strips were cast using the single roll caster equipped with the scraper. Mechanical properties of the strip were investigated by tension test, bending test and deep drawing. Mechanical properties of the strip cast by the single roll caster were as same as those made by DC casting.
Authors: Igor Grešovnik, Tadej Kodelja, Robert Vertnik, Božidar Šarler
Abstract: A framework for optimization of process parameters in material processing and production is described. The framework is designed for effective set up and solution of optimization problems as part of process design, as well as to support development of numerical models by inverse identification of model parameters. The general framework is outlined, which has been supplemented by a neural networks module in order to enable real time decision support. Simulator based on meshless method with radial basis functions (RBF) has been utilized.
Authors: Xue Feng Zhou, Feng Fang, Jian Qing Jiang
Abstract: Continuous casting has been widely applied in the production of steels and other metals. However, it has been rarely used in producing high speed steels, which are still manufactured by the conventional method of mould-casting. Thus, little is known about the microstructure of high speed steels made by the continuous casting technology. In the present work, AISI M2 steel is produced by horizontal continuous casting and the difference of solidification microstructure of ingots by different casting technologies has been examined. The results show that the networks of M2C eutectic carbides are greatly refined in the ingot by continuous casting compared to that by mould casting. Meanwhile, the morphology of M2C eutectic carbides changes from the plate-like type to the fibrous one, due to the increasing cooling rates. Compared with the plate-like M2C, the fibrous M2C in continuous casting ingots is less stable and decomposes faster at high temperatures, spheroidizing obviously after heating and refining dimensions of carbides.
Authors: Ryoji Nakamura, Kenta Takahashi, Masahiko Ikawa
Abstract: An unequal diameter twin roll caster was devised in order to increase productivity of the strip. This caster could cast the strip thicker than 6mm at the speed of 5m/min. The feature of this caster is that the lower roll was four times larger than the upper roll. The solidification length of the strip could be set longer easily than the conventional twin roll caster for aluminum alloy. Lowsolidification rate semisolid casting and low superheat casting were adopted. These were effective to increase the casting speed without decreasing the thickness of the strip. In the present study, the unequal diameter twin roll caster was designed and assembled. The test castings were operated and the characteristics of this caster were shown.
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