EFFECT OF HOMOGENIZATION ON SMALL DIAMETER BILLETS -AN EXTRUDER'S EXPERIENCE

摘要

Every extruder understands that extrusion billet homogenization is essential in the casting process. It is difficult to extrude non-homogenized billet especially when the billet diameter is large. However, many Asian extruders with small extrusion press are still using non-bomogenized billets as they doubt the effect of homogenization on small diameter billet. This article compares the effect of homogenization on 5" diameter billet through examining the extrusion pressure, speed, mechanical strength and surface finish of the extrusion. Experiments were carried out on three types of extrusion profiles namely simple solid, complex hollow and thin wall. The results showed that small diameter non-homogenized billet may be used if the extrusion is simple in shape and only minimal mechanical properties is required by the end-user. For better mechanical properties on the extrusion or complicated shape, it is better to employ homogenized billet although the billet conversion cost may increase slightly.