An Interpretation of Effect of Mn on Snoek Peak of Low Carbon Steels

Abstract

There are two interpretations for the decrease in carbon atom Snoek peak of low carbon steels by addition of manganese, i.e., decrease in solubility of carbon in ferrite and decrease in intensity of internal friction due to formation of carbon-manganese complex. Reported Snoek peak data are analyzed on the following assumptions, on the basis of the reported fact that the solubility of carbon in ferrite is not influenced by presence of manganese:
(1)Solute carbon atoms([C]) are distributed on interstitial sites adjacent to manganese atoms([Mn-C]) and on those free from manganese atoms([Free C]).
(2)Their partition between the two sites is in thermodynamical equilibrium.
(3)Carbon atoms contribute to internal friction in characteristic ways of the two types of occupying sites.
The analyzed data including newly measured ones on ageing process are consistently explained by these assumptions under the condition that the equilibrium partition is established at temperatures of measurements.