Iron Carbon diagrams over the Years


By:Cees van de Velde
First Edition: August, 2000


cvdv@home.nl

Year of publication:	1907
Authors :	P.Goerens
Source :	Über den augenblicklichen Stand unsere Kenntnisse der Erstarrungs-und Erkaltungsvorgange bei Eisenkohlenstofflegierungen, Metallurgie, Vol. (1907), pp.137-
	(The present situation of our knowledge of the solidification and cooling phenomena in iron carbon alloys.)

Notes:
The idea of the existence of a stable and a metastable system was mainly based on the theorethical assumption that undercooling could occur during solidification. Actual measurements showed that carbide formation took always place at lower temperatures as compared to temperatures where graphite formation took place. Differences, however, were hardly greater than the measurement accuracy that could be obtained at that time.
Another point that set doubt to the existance of two separate systems was the following:
When a liquid or solid is rapidly cooled by quenching, the situation as it existed at the time of quenching will more or less be fixed. When liquid cast iron is quenched, a complete white (carbidic) structure will be the result. This means that the actual condition in the liquid state had to be the same, i.e. a solution of iron-carbide in liquid iron. If, after solidification, graphite occurs in the structure, it must come from a secondary reaction, in this case the disintegration of ironcarbide.
So, two different views are formed, one advocating the stable and metastable system, and the other, of which Goerens is an example only believes in the existance of a metastable system, from which graphite can be formed during further cooling.



Image

German-English Translation.



Translation Zustandsdiagram f¨ur das System Eisen-Kohlenstoff, unter der Voraussetzung, dass der Graphit sekundär durch Zerlegung des Karbides entsteht.=Diagram for the Iron-Carbon system, supposing that graphite forms by a secundary reaction by desintegration of carbides.
Schmelze=melt
Mischkristalle=mixed crystals (solution of iron-carbide in iron)
Back to image