Abstract
A photographic study has been made of the appearance of the vapour–liquid mixture adjacent to the surface of a steel plate cooled in sodium polyacrylate solutions from 850°C to ambient temperature. This has been correlated with the variation of surface heat transfer coefficient observed during the quench. Novel structural features in this vapour–liquid mixture included a network pattern of continuous vapour rising up the plate surface separated by a static layer of froth. This structure was associated with a sudden drop of surface heat transfer coefficient and is probably responsible for the similarity of the quenching characteristics of Aquaquench ACR solutions and quenching oils. In other respects, this quenchant exhibited typical characteristics, namely, vapour blanket, nucleate boiling, and convective cooling stages. The duration of the vapour blanket stage increased as the polymer concentration of the solution increased.
MST/1652
Get full access to this article
View all access options for this article.