ISOTHERMAL EXTRUSION METHOD FOR METALLIC MATERIAL

摘要

PROBLEM TO BE SOLVED: To provide an effective method for isothermal extrusion by which temperature of an extruded product at an exit side of a die is kept constant during extrusion in an extrusion forming of a metallic material. SOLUTION: In the method a metal billet 12 contained in a container 10 is extruded through the die 20 keeping the temperature of the extruded product constant. The metal billet 12 is hearted and soaked to show a uniform temperature distribution in both axial and radial directions. The heating temperature of the billet 12 decided based on an extrusion force calculation formula and an extrusion temperature calculation formula led from a theoretical model so that heat generation due to shear deformation between the container and the billet balances with heat loss from the billet to the container. Charging of thus controlled billet into the container 10 enables the temperature of the extruded product at the exit of the die to be kept constant and the product temperature not to change during extrusion.