Effect of Ferrite Substructure on Precipitation of Fe₃C at MnS in an Ultra-low Carbon Steel

Abstract

The effect of ferrite substructure on precipitation of Fe₃C at MnS in in Al-killed steel was studied. By heat treatment, dislocation density and grain size were varied under the presence of MnS particles. By the subsequent aging at 603K and 703K, the ratio of Fe₃C precipitates nucleating on MnS with respect to the total number of Fe₃C precipitates was lowered under the presence of a larger number of dislocations and grain boundaries. It was considered that a MnS particle is less effective than a dislocation, and is comparably effective with a grain boundary is t heterogeneous nucleation site of Fe₃C in ferrite.