1990 Volume 76 Issue 3 Pages 422-429
The textures and precipitates formed in ultra low carbon Ti-added sheet steels containing varied amounts of Mn, P and Nb, by processing through cold rolling and continuous annealing, have been investigated for the development of a high strength sheet steel with a high r-value. A Ti-added steel alloyed with 1.4%Mn and 0.08% P has been found to meet the required mechanical properties. In the steels containing both Ti and P, the recrystallization texture showed a characteristic heating rate dependence ; that is, the faster the heating rate for annealing, the stronger the {111} texture components after recrystallization. FeTiP pre-cipitates were observed in the annealed steels but not in the hot rolled steels. An increase of Mn content suppressed the precipitation of Ti sulphide precipitates (TiS and Ti4C2S2) in the hot rolled steel, by form-ing MnS precipitates, and influenced the FeTiP precipitation. It was thought that the precipitation of FeTiP during the recrystallization stage influenced the texture development. The roles of Mn, P and Ti in the recrystallization texture control through the formation of fine FeTiP precipitates were discussed.
