低炭素鋼中の MnS の析出におよぼす酸化物の影響

概要

論文の詳細を見る
It has been known that precipitates of MnS become effective nuclei of intragranular ferrite during A_3 transformation and improve the ductility of steels. The objective of this work is to investigate the effect of oxide inclusions on MnS precipitation after solidification in order to obtain uniform distribution of precipitates. Various deoxidizing elements were added to low carbon steel melt of 1kg. This steel melt was solidified in an alumina crucible after some killing time. The nonmetallic inclusions were analysed by two-dimensional X-ray microanalyser on a cross-section of the ingot specimen. Among deoxidizing elements, the number of oxide inclusions of Hf, Ce, Y or Zr was greater and the distribution was more uniform than that of Al or Ti. The precipitation of MnS was followed effectively on those oxide inclusions between 1100 and 1400℃. The kinetics of precipitation was analysed by a precipitation model taking into account solidification and δ/γ transformation. The low diffusivity of Mn causes the depletion of Mn around MnS precipitates. It was considered that this Mn depletion promoted ferrite nucleation.
社団法人日本鉄鋼協会の論文
1989-03-01