RECRYSTALLIZATION TEXTURE CONTROL IN ULTRA-LOW CARBON TI-ADDED SHEET STEELS CONTAINING MN AND P

The textures and precipitates formed in ultra low carbon Ti modified sheet steels containing varied amounts of Mn, P and Nb by cold rolling and continuous annealing have been investigated for the development of a high strength sheet steel with a high r-value. A Ti steel alloyed with 1.4% Mn and 0.08%P meets the required mechanical properties. In 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 precipitates were observed in annealed steels but not in hot rolled steels. An increase of Mn content suppressed the precipitation of Ti sulphide precipitates (TiS and Ti4C2S2) in the hot rolled steel by forming MnS precipitates, it and influenced FeTiP precipitation. It is thought that the precipitation of FeTiP during recrystallization influenced texture development.