PURPOSE: To precisely estimate an extruding load in a hot extrusion of metal.

CONSTITUTION: A deformation resistance as the basis in the estimation of the extruding load, is obtd. based on an item composed o of the constant of each material decided by metal components, an item related to a strain under consideration of the constant of each material decided by the metal components and working-hardening index (n), an item related to a strain velocity d/dt under consideration of the constant of each material decided by the metal components and a strain velocity dependent index (m) and an item related to an absolute temp. Tk under consideration of the constant of each material decided by the metal components and a temp. dependent index E.