Process for cooling a casting billet during continuous casting

摘要

Cooling of a casting billet issuing from a continuous casting mould during continuous casting is effected by applying coolant directly to the billet surface. To reduce the arching of the billet foot, which occurs with unduly sudden cooling of the billet, polymers having a molecular weight from 10<4> to 10<8> are admixed to the coolant at least during the initial step. As a result of the polymer addition to the coolant, the kinetics of the formation and detachment of steam bubbles during the impingement of the coolant onto the hot billet surface is changed so drastically as a consequence of the great reduction in the surface tension of the coolant that an insulating film of coolant vapour, inhibiting the outflow of heat, builds up on the billet surface.