BLOWHOLE FORMATION DURING SOLIDIFICATION OF LIQUID STEEL

This paper deals with an analysis of the conditions leading to the for mation of blowholes during the solidification of liquid steel. The per itectic reaction, the effects of solidification on surface tension, th e enrichment of solutes and reactions between them during the solidifi cation are calculated and discussed. The results show that the main ga ses contributing to blowhole formation in liquid steel are H-2 and CO, the respective equilibrium partial pressures and their sum of which e xhibit maxima at the start of peritectic reaction of liquid steel duri ng the solidification. When this maximum pressure exceeds the sum of a tmospheric and ferrostatic pressures and additional pressure from surf ace tension, the blowholes would be formed. By this assumption the cri tical equation and domain diagram for controlling blowhole formation h ave been obtained.