The Dynamic Research On The Nonmetal Inclusion's Agglomeration And Growth In Molten Steel

Nonmetal inclusions in the molten steel have bad influence in the quality and capability on the steel products. At present the steel products develop along the high purity, high ingredients control precision and high performance stability, in which the high purity steel product is facing major challenge. In order to improve the level of purity in steel, people must reduce the content of inclusions. The primary methods of wiping off the inclusions are hastened the inclusions particles to collide, agglomerate, grow and float up.The cold and hot experiment are made out, the cold experiment of reaction of urea and aluminum foil and the hot experiment about molten samples incised from slab and processed in the high temperature microscope, gaining the connection between particles granularity and consistence, temperature and times in cold experiment, also selectively agglomeration and glomerate structure in collision process of the hot experiment.Calculate formulas about particles collision and growth are made into C program, applying various fractal dimension, collision times and primary densities, calculating the change of particles size and number densities. The results indicate: number density reduces by 7.1% when Brown collision time is 1 min , 43.5% when the time is 10 min, 70.1% when the time is 30 min. Collision degree of fractal dimension 2.1 is bigger than 3.0. When primary densities are bigger and collision times are more, collision and agglomeration degree is also bigger and number densities of great particles are more. Velocity gradient collision is more propitious to agglomerate than Brown collision. The results of Kumar and Uniform methods in the numerical models have a small distinction; the curves of number densities are close.The theory and application values are possessed for perfecting the dynamics theory of inclusions growth and optimizing the technique of smelting exceed clean steel.