An increase of the level of strength of low-carbon steels in many cases is accompanied by considerable worsening of their ductility. A simultaneous increase of strength and ductility is possible provided the formation of a structure with a stably small austenite grain before accelerated cooling. A broad investigation of the structure-formation process and its relation to the level of mechanical properties is required for selecting the optimal temperature and strain-rate parameters (under conditions realized during operation of the finishing group of the mill). The most important component of the hot-rolling regime-structure-rolled product properties system is the relation between the hot-rolling regimes (temperature of the stands, speed, reduction) of metal in the continuous group of the wide-strip mill and the structure, in particular, ferrite and pearlite grain size, It is known that a change in grain size as a consequence of cold working-recrystallization processes occurs during fractional hot deformation of metal in a single-phase condition.
展开▼
