Papers by Keyword: Billet

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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: Vlad Mureşan, Mihail Abrudean
Abstract: In this paper, a solution for the automatic control of the driving mechanisms that load/unload billets in/from a rotary hearth furnace is proposed. This problem is approached because in the actual stage the control of the loading/unloading machines is made manually. The treated solution is based on using, for each machine, a direct-current motor (d.c. motor) supplied through a direct-current converter (d.c. converter) for the forward-backward moving of the two machines to/from the furnace. In this context, the tuning of the controller implemented in the converter is made in order to assure the imposed speed of the motors and implicitly of the machines, respectively an appropriate speed evolution of the motors in the period of their acceleration and deceleration to assure the machines correct positioning.
Authors: Jung Ho Moon, Tae Kwon Ha
Abstract: M2 steels, the typical Co-free high speed steel (HSS) possessing hardness level of 63~65 HRc, are most widely used for cutting tools. On the other hand, Co-containing HSS’s, such as M35 and M42, show a higher hardness level of 65~67 HRc and used for high quality cutting tools. In the fabrication of HSS’s, it is very important to control cleanliness and eutectic carbide structure of the ingot and it is required to increase productivity at the same time. Production of HSS ingots includes a variety of processes such as casting, electro-slag remelting (ESR), forging, blooming, and wire rod rolling processes. In the present study, electro-slag rapid remelting (ESRR) process, an advanced ESR process combined by continuous casting, was successfully employed to fabricate HSS billets of M2, M35, and M42 steels. Distribution and structure of eutectic carbides of the billets were analysed and cleanliness, hardness, and composition profile of the billets were also evaluated.
Authors: Myoung Gyun Kim, Jong Ho Kim, Joon Pyo Park, Gyu Chang Lee, Woo Jin Kim
Abstract: Currently, magnesium billets produced by ingot casting or direct chill casting process, result in low-quality surfaces and peer productivity. Continuous casting technology for high-quality surface billets with fine-grained and homogeneous microstructure can be a solution for the cost barrier breakthrough. The latent heat of fusion per weight (J/g) of magnesium is similar to that of other metals, however, considering the heat emitted to the mould surface during continuous casting in meniscus region and converting it to the latent heat of fusion per volume, magnesium will be rapidly solidified in the mould during continuous casting, which induces subsequent surface defect formation. In this study, electromagnetic casting and stirring (EMC and EMS) techniques are proposed to control solidification process conveniently by compensating the low latent heat of solidification by volume and to fabricate magnesium billets with a high quality surface.
Authors: G. Alvarez de Toledo, A. Arteaga, J.J. Laraudogoitia
Abstract: Surface defects, mainly intergranular cracks (IGC), in as cast billet is the main concern for the production of microalloyed steels with the continuous casting process. A description is given of the IGC in the as cast billet surface and the main casting parameters influencing its formation. An analytical model of the influence of the microalloyed content in the formation of precipitates and the corresponding billet surface ductility at the temperature of billet straightening is presented. The model was validated with bibliographical ductility experimental values and was used to perform composition optimisation for continuous casting production. The analytical approach has been completed with a numerical precipitation model coupled with a continuous casting billet solidification model. The coupled program allows precipitate size distribution calculation in selected points of the cross billet section as a function of production parameters, steel composition and billet size. These precipitate distributions are important to detect ductility problems in billets and to optimise the operational parameters so as to avoid these problems.
Authors: Chang Rong Li, Zhen Yao, Zhao Hua Liang
Abstract: Continuous casting process parameters such as casting speed, superheat, secondary cooling water flow rate have greatly affections to central defects in SWRH82B billet. These parameters were investigated by the methods of chemical content analysis and etch test for macrostructure in some steel plant of china. The results shows that the central defect of SWRH82B billet can be improved when the superheat is controlled at the range of 15~25°C, casting speed is 1.80m•min-1 and secondary cooling water flow rate is 0.72 L•kg-1.
Authors: Yan Ling Zhang, Xiao Gang Yang, Jin Gui Xu, Li Guo Bai
Abstract: In this study, the temperature field distribution of 22CrMoH billet is first obtained by simulating continuous casting process using moving boundary method. On the basis of the above data, the microstructure of 22CrMoH gear steels billet was simulated based on CAFÉ (Cellular Automaton – Finite Element Analysis) method, together with the effects of alloying elements such as Cr, Mo, Si, Mn on the microstructure of this billet. The simulated result agrees reasonably well with that of the actual product. And it suggested that under the reasonable extend of current steel grade, the increased amount of Si and Mn can steadily widen the proportion of equiaxed grains, lead to the increase in equiaxed grain amount, hence the decrease in equiaxed grain average radius; The increase in Mo content is able to enhance the nucleation amount; Proper decrease in Cr content favors the increase in proportion of equiaxed grains, but little effects on grain’s amount and radius. Further, the composition of alloy elements under the specified scope of 22CrMoH grade was optimized and the simulated results showed that the microstructure has vastly improved, as the proportion of equiaxed grain rose nearly doubled, the grains amount has increased by 19.96%, and average radius has decreased by 9.20%.
Authors: Kwan Do Hur, Hyo Young Lee, Hong Tae Yeo
Abstract: Aluminium alloys have been widely used in the structure of aircraft and passenger car because of its lightweight. It is also interested in the lightweight products to improve the fuel efficiency. In this research, forging design of Al rotating arm holder has been studied by FE analysis. Structural analysis of the model was performed at first. From the results of the analysis, effective stress, effective strain and safety factor acting on the component were obtained.
Authors: A.M. Stolyarov, Marina V. Potapova, M.G. Potapov
Abstract: The influence of the St.3sp, 40 and 85 steel grades chemical composition, temperature of the metal in the tundish ladle, billet cross-sectional dimensions (150 × 150 and 152 × 170 mm), the sulfur content in the metal on the speed of withdrawal of the billets from the CCM mold has been investigated. It was established, that the change of the metal temperature in the tundish ladle of the CCM has the greatest effect on the billet withdrawal speed, the change of carbon content in the steel and the billet cross-sectional dimensions influence in less extend, and the sulfur content in the cast steel does not affect at all.
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