DETERMINATION OF THE STRESSED METAL STATE DURING HOT ROLLING BY THE FINITE ELEMENT METHOD

Abstract

Purpose. Determination of the stress-strain state of the metal during the rolling of large ingots to prevent the occurrence of internal defects, and determining the effect of forced cooling of the ingot surface during hot rolling on the stress-strain state.
 Research methods. Finite element method, upper estimate method.
 Results. Based on the finite element method, a comparative simulation of the stress-strain state of the ingot with different cooling times was performed. As a result of the study, it was established that the forced cooling of the ingot surface during hot rolling helps to reduce the probability of the internal continuity defect forming. The given results of comparison of the distribution of strain intensity along the rolling cross-section in the basic version and with additional annealing indicate a decrease in the probability of formation of discontinuities in the axial zone of the ingot. This, in turn, proves the effectiveness of forced annealing of the surface layers of the ingot (workpiece).
 Scientific novelty. A mathematical model of the distribution of the main stress state components was developed. It took into account the redistribution of temperatures and, as a result, the mechanical properties of the metal according to the height of the deformation focus during the hot rolling of relatively large blanks.
 Practical value. The use of forced cooling leads to a significant increase in hydrostatic and normal stresses in the axial zone, reducing the probability of the formation and subsequent growth of internal continuity defects. Thus, the quality of finished products increases, in particular, valuable rolled products made of special grades of steel.