Couple Numerical Simulation Of Flow And Temperature Field Of Continuous Casting Mold At Low Superheat By Two Rollers Cooling

A kind of low superheat forces pouring technology is introduced in this paper, that is, the liquid metal is poured into mould by cooling roller, a new approach is introduced to solve the problem of water mouth blinding in low-superheat casting technology. By the aid of CFD business software—Fluent, flow field, temperature field and solidification field of the molten steel in mould are simulated and analyzed for billet casting mold and thin slabs casting mold poured by two rollers cooling in low superheat at different pull velocity. At the same time, the conclusion is compared with the flow-state and solidification of the molten steel in mould with immersion water mouth poured. Finally, in order to verify the validity of simulation data, the macro organization and mechanics characters of aluminum ingot which is cooled through"U"pipe at low superheat casting are studied for the experimental material of 99% industrial aluminum. The conclusion in the paper show:(1) For the refrigeration by cooling roller, the steel liquid is poured into mould realizing the purpose of casting at lower superheat. As the increasing of pull velocity, the cooling roller actions play down relatively.(2) Flow field shows that steel liquid is poured into mould by cooling roller and form shock stream downward. On the one hand, the shock stream breaks up the syllogistic crystal of solidification front, then the new driving force will be formed and the isometric crystal rate will be enlarged. On the other hand, the shock stream brings convolute backset at certain depth, which is helpful to exclude the field trash in steel liquid and melt the protecting dregs.(3) Compared with immersion water mouth casting, the distribution of temperature field and the growing of solidification shell of the steel liquid in mould by two rollers cooling casting at low superheat are uniform. Moreover, the steel liquid in mould by two rollers cooling casting at low superheat has little gradient of temperature and wide two-phase district of liquid and solid. It is favorable to raise paraxial crystal rate, inhibit syllogistic crystal growth, and degrade center-segregation, defect rate of loose and slight crackle in the organization of casting slab.(4) With the experimental material of industrial aluminum, the result shows that macro organization of the aluminum ingot casting by cooling rollers at low superheat is improved and its ultimate stress is refined greatly.