Aluminium Extrusion

i am not succeess in extrusion of solid round bar of boron/aluminim,

i use regular shape die or conical both die i use for,

but the surface finish is not ok it very ruf finish,

material is AL3B (Aluminium 97% + Boron 2.5 to 3%)

extrusion speed is 5 to 9 mm

temp is 400 to 420 degree celcius

billet size 85mm

road size 45mm

container length 17 Inch

Die which i use is one conical type the other is bearing type 5 & 25 mm

tempture and pressure is ok but i request u pls any

one have idea about the die shape so i request to suggest me

-------pankaj