COMPUTER-SIMULATION OF BLOWHOLE FORMATION IN RIMMING STEEL INGOTS

A computer model used to predict blowhole formation during solidificat ion of rimming steel is presented. The position of the blowholes is de termined by the interaction between the solidification front and the b uoyancy of the carbon monoxide bubbles, itself dependent on the bubble size and on the viscosity of the steel. The distance at which the fir st blowholes appear, as predicted by the model, is correlated with sam ples taken from ingots that were later hot- and cold-rolled into thin strip. It is concluded that the surface quality of the strip depends o n skin thickness, which is affected by rimming action and teeming spee d.