On the Cold Backward Extrusion of Steel

Abstract

The cold backward extrusion process was applied to the pressing of low carbon steels or JIS S 10 C and S 20 C, used for mechanical construction, and was compared with the forming process of aluminium, copper and their alloys. As to measurement, the new types of the load dynamometer and displacement measuring device utilizing electric resistance wire were laid out and, load and stroke of the punch were measured simultaneously without the aid of the electric amplifier. Then relation between maximum load and area reduction, effect of working velocity, and hardness distribution of extruded shells were obtained in this process.