Effects of stretching processing parameters on the mean elongation ratio and maximum spread ratio of heavy forgings

Abstract

Heavy forgings are the essential parts of some nuclear, electrical power generation, rolling mill equipments. The rigid-viscoplastic finite element models (FEM) were established to study the effects of processing parameters (deformation degree, tool width ratio, blank width ratio, strain rate, friction, and forming temperature) on the mean elongation ratio and maximum spread ratio of heavy forgings during stretching process. A new formula (LD model) is proposed to predict the mean elongation ratio for stretched heavy forgings. The predicting capabilities of LD model were verified by experiments. Results show that: (1) The mean elongation ratio and maximum spread ratio increase with the increase of deformation degree; (2) When the tool width ratio is decreased, the mean elongation ratio increases and the maximum spread ratio decreases; (3) When the blank width ratio is increased, the mean elongation ratio increase and the maximum spread ratio decrease; (4) The mean elongation ratio is not affected by strain rate, friction, and forming temperature. However, the effects of these three process parameters on the maximum spread ratio of deformed block are significant; (5) There is a good agreement between the experimental results and predictions by LD model, which confirms that the proposed LD model is valid for the practical industrial productions.