Pressure behavior in equal-channel angular hydroextrusion

Abstract

The equal-channel angular hydroextrusion (ECAH) is a version of the well-known method of equal-channel angular extrusion of the billets. Some features of ECAH associated with using fluid for transfer of the force influence from the plunger to the billet were investigated. It has been established that the pressure drop from the maximal level at the beginning to a lower stable level and constant pressure during the later stage of the process are features of dependence of ECAH pressure on the plunger displacement. Such features of the ECAH are similar to those of the direct hydroextrusion of a billet. It has been shown that the relative volume of the fluid used under ECAH should be reduced to a minimally allowable amount in order to restrict the magnitude of pressure oscillations. The scheme of new ECAH facility for long-length rods was proposed.

Keywords:

• hydroextrusion
• equal-channel angular extrusion
• severe plastic deformation
• ultrafine-grained metals