An AISI 1045 steel billet is to be coldextruded from a 25mm

. An AISI 1045 steel billet is to be cold-extruded from a 25-mm diameter to a diameter of 16 mm. As the process engineer:

(a) suggest a suitable lubricant and justify.

(b) suggest the metallurgical condition of the billet and justify.

(c) design in principle, a die shape which will avoid problems and justify.

Solution

(a) Stearate type soaps are commonly used for cold extrusion of steels at room temperatures. It can withstand high pressures and adheres strictly to the surface of the coating applied on the billet.

(b) Large plastic deformation occurs in the billet and result in grain orientation and change in grain elongation, giving rise to inhomogenuos stress distribution. Thus, the microstructure near the surface is less homogenuous and less elongated.

(c) A hollow rectangular die is to be uses, where metal flow is not restricted.