INTERFACE FRICTION IN HOT METAL DEFORMATION.

Abstract : An investigation was carried out on interface friction between workpiece and die material under conditions of hot plastic deformation. The plane-strain compression technique was used for determining the magnitude of friction between 7075 Al, Ti-6Al-4V, 4130 steel, TZM, Inconel X750 and Be specimens (representing the workpiece) and 4340, H-11, WC and Al2O3 anvils (representing the die). Calculated coefficients of friction, combined with observations of surface appearance, showed that sticking friction is the dominating mechanism. Sliding friction was promoted by some oxides formed on specimens and, possibly, by some surface treatments applied to anvils. (Author)