A direct extrusion operation produces the cross section shown in Figure P19.32(c) from an aluminum billet whose diameter = 150 mm and length = 500 mm. The flow curve parameters for the aluminum are K = 240 MPa and n = 0.16. In the Johnson strain equation, a = 0.8 and b = 1.2. 

Determine (a) the extrusion ratio, 

(b) the shape factor,

(c) the force required to drive the ram forward during extrusion at the point in the process when the billet length remaining in the container = 400 mm, 

(d) the length of the extruded section at the end of the operation if the volume of the butt left in the container is 600,000 mm³.

 

LL 55 25 85 (d) FIGURE P19.32 Cross-sectional shapes for Problem 19.32 (dimensions are in mm: ta) rectangular bar, bi tube, Ia channel, and (di cooling fins