Forgiatura La Metallurgia Italiana -n

Abstract

INTRODUCTION Friction is a major factor in determining the characteristics of metals as they are formed. In forging, friction is a key factor in the pattern of metal flow and die wear. In general, excessive friction has a negative influence on die wear, product quality, product cost, and productivity. It is therefore common to use various lubricants to reduce friction during metal forming operations. Major factors affecting friction include the normal stress along the die-material interface, the lubrication condition, the relative velocity, the temperature, the roughness and the mechanical properties of the material and/or the die. A detailed investigation of these factors is not easy because the die-material interface in metal forming is under high pressure and temperature. Thus, friction in this area is still somewhat of a mystery even though many researchers have performed detailed studies in various ways for a long tim