Abstract
	Cogging in shaped dies (e.g. V-dies, swage dies, V-die and flat-die combinations) is highly recommended when forging ingots are made of materials with poor formability. However, the dies shape imposes some limitations that must be taken into account during development of the proper forging procedure. The cogging pass schedule design cannot be based only on efficiency of the stock dimension changes. To achieve the high quality of a final product, the as-cast structure defects have to be eliminated during cogging process. Metallurgical defects are localized mostly near the ingot centreline. Therefore, such variants of cogging parameters should be selected that produce large deformation of the ingot core under triaxial compressive state of stress. The bite ratio, the individual reduction in height and the workpiece aspect ratio are the cogging parameters that have the most crucial influence on the local mechanical states in the deformation zone as well as the elongation efficiency. This paper presents some results of numerical simulations of cogging in V-dies (with 135° angle between their working surfaces) that have been conducted in order to find out the effect of the mentioned process parameters on the local mechanical states at the deformation zone. Research results together with conclusions coming from the relevant literature review have allowed to establish the rational recommendations to select the appropriate parameters of cogging in the analyzed type of dies.