Development of a Cold Extrusion Part from Design to Production.

This paper describes the development of a shock-absorber tube which is placed between car and bumper. For reasons of weight an aluminium (H 14) alloy was chosen. The slugs are soft annealed before extrusion. A special lubricant of an oil-PbO base was found out to prevent surface defects and to reduce the punch-pressure. Eccentricity of the can was about 0. 4 mm. This value could be reduced significantly by a special treatment of the slugs after annealing. Difficulties arose during the forming of a bead in the 4. 4 mm wall. With a special beading-die, using plastic material, these were solved.