Simulation On Twin Roll Casting And Laser Strengthening On304Stainless Steel

Recently, the twin roll casting process has attracted the attention of the world steelindustry because of its low cost, short production period and high efficiency. However, thecracks often are initiated on the surface during the twin roll casting. To solve this problem,a3D coupled fluid-structure model was established By CFX and the thermal flowcoupling field was simulated. Then according to the result of the temperature field, thestress field of the molten pool was simulated. Furthermore, the laser remelting technologywas conducted to improve the microstructure and corrosion resistance of the surface.The simulation on the thermal flow coupling field shows a large area of vortex existsin the molten pool. The heat transfer mechanism between the molten pool and rollcontains direct heat transfer and air gap heat transfer. With the increase of casting speed orpouring temperature, the temperature of the molten pool increases and the solidificationpoint moves toward the outlet. According to the solidification point position, the processparameter of twin-roll casting was optimized. In order to obtain a strip with good quality,the casting speed should be0.39m/s.The simulation on the stress field shows that the stress of the molten pool distributesmainly on the contact surface between the molten pool and roll. The risky points arelocated at the outlet, specially, close to the center of molten pool and side dams. With theincrease of casting speed or pouring temperature, the stress of the molten pool decreases.According to the fracture possibility at the outlet, the process parameter of twin-rollcasting was optimized. In order to avoid the cracking problem, the casting speed should becontrolled larger than0.2m/s and less than0.4m/s.The laser remelting result shows that on the surface of AISI304stainless steel treatedby laser remelting, the microstructure is refined obviously. With the increase of thescanning speed, the refinement of microstructure and the improvement of corrosionresistance are enhanced. The rare earth oxide additive can also enhance the microstructurerefinement and the corrosion resistance improvement.