Blowhole formation during solidification of liquid steel

Abstract

This paper deals with an analysis of the conditions leading to the formation of blowholes during the solidification of liquid steel. The peritectic reaction, the effects of solidification on surface tension, the enrichment of solutes and reactions between them during the solidification are calculated and discussed. The results show that the main gases contributing to blowhole formation in liquid steel are H2 and CO, the respective equilibrium partial pressures and their sum of which exhibit maxima at the start of peritectic reaction of liquid steel during the solidification. When this maximum pressure exceeds the sum of atmospheric and ferrostatic pressures and additional pressure from surface tension, the blowholes would be formed. By this assumption the critical equation and domain diagram for controlling blowhole formation have been obtained.