Papers by Author: Yan Juan Jin

Abstract: In the paper a inner-outer couple cooling technology of molten steel for 1240×200mm slab continuous casting, that is to set an inner cooler-U shape pipes in the mold, is put forward in order to enhance the efficiency of transmitting heat and improve the flow status of molten steel. The flow status of molten steel in inner-outer couple cooling mold is simulated by using fluid dynamics software. It is found that setting inner cooler in the mold can make molten steel flow status even, which partly act as electromagnetic trig and is favorable to inclusion in molten steel floating up.

Abstract: In the paper, flow status and solidification status of molten steel in inner-outer couple cooling mold in the filling process are simulated by using fluid dynamics software Flow-3d, and obtain distributing diagrams of flow field and temperature field and free-surface shape diagrams in the filling process. Influences of flow field and temperature field of filling process on solidification are analyzed in the slab continuous casting. It is indicated that inner cooler can improve molten steel flow status, which is favorable to inclusion in molten steel floating up, quicken the solidification rate of molten steel in the mold.

Abstract: A new technology of high efficiency concasting based on inner-outer couple cooling of molten steel in a mould has been advanced, that is to set an inner cooling apparatus, U shape pipes, in a mould. The flow status of molten steel in mould with inner cooling apparatus is analyzed by using fluid dynamics analysis software FLUENT, and compared with that without inner cooling apparatus. It is found that the inner U-shape cooling apparatus can make molten steel flow with a lower impact depth which is favourable to inclusion in steel floating up.

Abstract: Mold filling and solidification of molten steel for 750mm×450mm×300mm continuous casting mold of single SEN and double SEN are simulated by using CFD commercial code Flow-3d. The distributing diagrams of velocity field and temperature field and the location and shape diagrams of free-surface during mold filling process are obtained. Influences of single SEN model and double SEN model on velocity field and solidification are analyzed. It is found that double SEN model can lighten circumfluence intensity at the upper of mold, quicken solidification speed of steel liquid in the mold, which is favorable to improving the quality of billet and enhancing pull speed.

Abstract: The numeric simulation of effect of X-shape submerged nozzle on flow of molten steel in a mold for 160mm×160mm concasting billet has been carried out by viscous fluid mechanics theory and CFD software Fluent. It was verified that during pouring with X-shape submerged nozzle, the vortex molten steel entering into mold by guide of vortex guidance channel which was formed with top and bottom surface of two semioval flow guidance plate and invert taper pipe to availably reduce impact depth, promote inclusion and gas bubble aggregating and floating off, and improve concasting efficiency.

Abstract: In order to study dynamic mechanical properties of concrete, the impact compression tests of concrete material under three different velocities are conducted using a light gas gun. Flyer and target are made of the same material, the manganin pressure gauge is used to measure the time-pressure curves of the samples. The measured time-pressure curves show that the stress peak will increase with the increase of flyer speed, and the stress peak at different locations will decrease with the increase of dissemination distance. It illustrate that concrete material has obvious rate sensitivity and energy dissipation characteristics. Then, through further analysis of the experimental data, the shock hugoniot relationship is determined, that is a linear relationship between the shock wave speed and the wave particle velocity. Based on the shock hugoniot data of the concrete, the high-pressure polynomial equation of state is fitted.

Abstract: An inner-outer coupled cooling technology of molten steel for 1240×200mm slab continuous casting, that is to set an inner cooler—U shape pipes in the mold, is put forward in order to enhance the efficiency of transmitting heat and improve inner structure of billet. The flow status and solidification status of molten steel under coupling flow field and temperature field in inner-outer coupled cooling mold are simulated by using fluid dynamics software, and compare with those in traditional mold. It is found that setting inner cooler in the mold can make molten steel flow status even, which is favorable to floating up of the inclusion, quickening the solidification of steel liquid and improving the quality of billet.

Abstract: In view of the process of flowing steel before the establishment of strip casting, the low superheat forced pouring continuous casting technology, i.e. the molten steel is cooled by the rotating cooling rollers, then it is forced to flow into mold, has been put forward in order to reduce superheat of liquid steel, enhance the efficiency of heat transfer and improve inner structure of billet. The filling and solidification processes of low superheat casting and submerged entry nozzle(SEN) casting are numerical simulated using fluid dynamics software. It is gained that velocity distributing diagrams, temperature distributing diagrams and solidification distribution diagrams at different time in the filling process. Influences of twin-roller cooling pouring on velocity field, temperature field and solidification are analyzed. The results show that the superheat of liquid steel is decreased and the solidification rate of liquid steel is increased by low superheat casting of twin-roller cooling process, which is favorable to improving the quality of billet and enhancing pull speed.