Study On Process Of Secondary Cooling Solidification Of CSP Thin Continual Casting Slab

The secondary cooling is of central importance in continuous casting process, so it is necessary that secondary cooling of new caster is studied. Secondary cooling of strand is to determine according to steel grade, product dimension, casting temperature, casting speed. Adjustments and optimizations on the interrelated coefficient can achieve aim of instructing industrial production and increasing quality of slab.A two-dimensional mathematical model of solidification and heat transfer in continuous casting of thin slab has been developed according to actual circum -stance of Handan Iron and Steel Company CSP in this thesis. The process of solidification of slab is simulated in aid of potential finite element software-MARC and using two-dimensional cutting slice method. By comparing the actual results measured in Handan Iron and Steel Company with the value of the model, it proves that the result of numerical simulation is reliable and the model is accordance to fact within permission of error. And solidification principles of slab during secondary cooling are concluded according to the value of the model.Longitudinal surface cracks have often been found at 300mm to the edge in width of thin slab, so the feasible advice is put forwarded. The quantity of water has changed, then the inner temperature field of thin slab has been amended and the temperature grads have been reduced in width and the cracks are lessened by reducing cooling water quantity at the center of wide surface and increasing cooling water quantity at the transition of wide surface properly.Because of producing requirement, the relation between technical parameters (casting speed, superheat and cooling intensity etc.) and solidifica -tion parameters( external temperature of slab, solid thickness at end of mould and liquid pool length) has been constituted in the way of numerical simulation.It is indicated that solid thickness at end of mould is lessening, external temperature of slab is falling slower and liquid pool length is extending when casting speed or superheat rises. And when water quantity increases, external temperature of slab is rising faster, and liquid pool length is shortening, but solid thickness at end of mould is hardly affected. Besides, changing of water quantity causes influence on heat transfer and solidification of slab in the secondary cooling process which has the characteristic of coupling from above to below.