Reason for the Beneficial Effect of Sulfur Additions on the Hypoperitectic Reaction in a 0.1 Pct Carbon and the Sulfur Content Needed to Establish the Effect

It has been shown that the addition of 0.3 pct sulfur to the 0.1 pct carbon, 0.9 pct manganese, and 0.3 pct silicon peritectic steel does not exhibit a rippled shell because of the accommodation of the buckling strains by the presence of a significant amount of low-melting point liquid when solid austenite and ferrite are formed. A similar solidification path will exist for sulfur contents down to approximately 0.1 pct for this alloy. A significant amount of low melting liquid will be present down to that sulfur concentration. The exact point for the disappearance of the peritectic effect still must be determined experimentally, but it certainly is in the range of 0.1 to 0.15 pct sulfur. For other peritectic alloys, the approximate sulfur content at which the effect of the peritectic reaction will disappear can be determined similarly to the method used in this study.