Results presented in this paper contribute to the investigation of the effect of annealing temperatures ranging from 800 to 1000 ℃ on the dynamic impact mechanical properties of high manganese TWIP steel. The propert...Results presented in this paper contribute to the investigation of the effect of annealing temperatures ranging from 800 to 1000 ℃ on the dynamic impact mechanical properties of high manganese TWIP steel. The properties were measured by using an instrumented Charpy impact tester. The impact absorbing energy initially increases with the annealing temperature, climaxes at 900 ℃, and then decreases. The dynamic crack extension resistance curve indicates that the crack initiation force decreases with the annealing temperature, and the steel annealed at 900 ℃ has the best ability against crack expansion展开更多
Using the equation of continuity and the double equation of Navier-Stokes and k-ε, numerical modeling on a single outlet continuous casting tundish has been carried out during the process of non-thermal flow coupling...Using the equation of continuity and the double equation of Navier-Stokes and k-ε, numerical modeling on a single outlet continuous casting tundish has been carried out during the process of non-thermal flow coupling. The flow field distribution inside the tundish was calculated and the viscosity response time was calculated with the mass transfer equation based on the flow field distribution. The flow characteristics of the molten steel inside the tundish were analyzed, with the results of the numerical modeling compared to the hydraulic modeling. The results showed that the Resident Time Distribution （RTD） curves in the latter anatomosed comparatively better. This certified the validity established by the mathematical model. Numerical modeling was carried out on both large and small tundishes during the processes of thermal flow coupling and also thermal non-flow coupling. The results showed that in regards to large tundishes with relatively simple flow processes, using numerical modeling for thermal flow coupling is necessary.展开更多
Targeting the single tuyere and double tuyere methods of argon blowing for Baosteel＇ s 300 t ladle furnace, the 3D continuity equation, the N-S equation and the turbulent k-ε double-equation were used to model the f...Targeting the single tuyere and double tuyere methods of argon blowing for Baosteel＇ s 300 t ladle furnace, the 3D continuity equation, the N-S equation and the turbulent k-ε double-equation were used to model the form of the molten steel flow and the dead areas under six different argon blowing conditions. The different flow field forms and the degree of mixing under different argon blowing methods were compared. The results demonstrate that when large ladles are operated via different methods of argon blowing, the spray from the centre of a single tuyere forms a symmetrical vortex, while when a double tuyere sprays, there is basically no clear vortex. In regards to the amount of argon blowing that will produce the best blend of molten steel, the amount of dead area reduction will not be clearly noticeable if there is an excessive argon blowing amount.展开更多
The material selected for this work was the spray formed Vanadis4 high alloy cold working mould steel （abbreviated to V4 steel）. Its microstructure, hot rolling process, and annealing treatment have been investigate...The material selected for this work was the spray formed Vanadis4 high alloy cold working mould steel （abbreviated to V4 steel）. Its microstructure, hot rolling process, and annealing treatment have been investigated. Observed from the optical and electron microscopes, the as-sprayed V4 steel had the finer microstructure of uniform and equiaxial grains ,while after hot rolling for densification and spheroidized annealing, the V4 steel obtained an excellent spheroidized structure that is favorable to subsequent quenching and tempering treatment. The spheroidized structure and level of annealed hardness of the V4 steel are almost the same as expensive imported powder metallurgy the V4 steel. It is difficult to produce V4 steel with the conventional ingot metallurgical technique, so the multi-step and high-cost powder metallurgy method is generally used at present. Compared to the powder metallurgy technique, using the spray forming technique to produce the V4 steel has obvious advantages and potential market competitiveness in reducing production costs, simplifying working process, and shortening the production cycle.展开更多
基金the Key Research Foundation of Baosteel(No.D06EBEA207).
文摘Results presented in this paper contribute to the investigation of the effect of annealing temperatures ranging from 800 to 1000 ℃ on the dynamic impact mechanical properties of high manganese TWIP steel. The properties were measured by using an instrumented Charpy impact tester. The impact absorbing energy initially increases with the annealing temperature, climaxes at 900 ℃, and then decreases. The dynamic crack extension resistance curve indicates that the crack initiation force decreases with the annealing temperature, and the steel annealed at 900 ℃ has the best ability against crack expansion
文摘Using the equation of continuity and the double equation of Navier-Stokes and k-ε, numerical modeling on a single outlet continuous casting tundish has been carried out during the process of non-thermal flow coupling. The flow field distribution inside the tundish was calculated and the viscosity response time was calculated with the mass transfer equation based on the flow field distribution. The flow characteristics of the molten steel inside the tundish were analyzed, with the results of the numerical modeling compared to the hydraulic modeling. The results showed that the Resident Time Distribution （RTD） curves in the latter anatomosed comparatively better. This certified the validity established by the mathematical model. Numerical modeling was carried out on both large and small tundishes during the processes of thermal flow coupling and also thermal non-flow coupling. The results showed that in regards to large tundishes with relatively simple flow processes, using numerical modeling for thermal flow coupling is necessary.
文摘Targeting the single tuyere and double tuyere methods of argon blowing for Baosteel＇ s 300 t ladle furnace, the 3D continuity equation, the N-S equation and the turbulent k-ε double-equation were used to model the form of the molten steel flow and the dead areas under six different argon blowing conditions. The different flow field forms and the degree of mixing under different argon blowing methods were compared. The results demonstrate that when large ladles are operated via different methods of argon blowing, the spray from the centre of a single tuyere forms a symmetrical vortex, while when a double tuyere sprays, there is basically no clear vortex. In regards to the amount of argon blowing that will produce the best blend of molten steel, the amount of dead area reduction will not be clearly noticeable if there is an excessive argon blowing amount.
文摘The material selected for this work was the spray formed Vanadis4 high alloy cold working mould steel （abbreviated to V4 steel）. Its microstructure, hot rolling process, and annealing treatment have been investigated. Observed from the optical and electron microscopes, the as-sprayed V4 steel had the finer microstructure of uniform and equiaxial grains ,while after hot rolling for densification and spheroidized annealing, the V4 steel obtained an excellent spheroidized structure that is favorable to subsequent quenching and tempering treatment. The spheroidized structure and level of annealed hardness of the V4 steel are almost the same as expensive imported powder metallurgy the V4 steel. It is difficult to produce V4 steel with the conventional ingot metallurgical technique, so the multi-step and high-cost powder metallurgy method is generally used at present. Compared to the powder metallurgy technique, using the spray forming technique to produce the V4 steel has obvious advantages and potential market competitiveness in reducing production costs, simplifying working process, and shortening the production cycle.
