METAL FLOW DURING EXTRUSION OF NON-CIRCULAR SECTIONS

Beata Pawłowska

doi:10.12776/ams.v20i1.182

Abstract

The paper presents the analysis of nature of metal flow during extrusion of non-circular sections and determining the relationship between extrusion force and geometrical parameters of extrudate (the shape of the extrudate). Experimental procedure was curried out for the simplest cases of non-circular profiles (triangle, square, rectangular) of various geometrical parameters. The extrusion load and punch displacement have been registered during experimental work. By determining parameters of metal plastic flow (the depth of plastic zone Lp and the dead zone angle sm) it has been shown the difference in nature of metal flow during extrusion product differing in non-circular sections. This differentiation results in the complex nature of flow consequential from change with circular section of the billet to non-circular section of extrudate.It has been shown that flow resistance can be different with regard to appearing configurations of deformation zones (the size and shape of plastic zone, dead and shear zones) and dependent from for example geometrical parameters of a die (shape and size of an die orifice).

Highlights

The possibility to obtain products of different shapes mainly from aluminium and aluminium alloys, e. g. in the aspect of complexity of the shape and thin-walled sections are difficult to determine with regard on insufficiently examined processes of deformation as well as the side of description of mechanical behaviour of the material and the technology
Analysis of the indicated manner of plastic flow basing on grid distortion have supplied data, which have allowed to determine the depth of plastic zone, its shape and the value of the dead zone angle
The dead zone angle sm and depth of plastic zone Lp increases with no regularity of the shape of the cross-section meaned by number of corners or number of axis and plane of symmetry

Summary

Introduction

The possibility to obtain products of different shapes mainly from aluminium and aluminium alloys, e. g. in the aspect of complexity of the shape and thin-walled sections are difficult to determine with regard on insufficiently examined processes of deformation as well as the side of description of mechanical behaviour of the material (the change of structure and properties) and the technology (the selection and controlling the parameters of process). The differentiation in size and shape of deformation in dependence on the shape of extrudate cross-section and extrusion load is especially visible in the case of extrusion of nonaxisymmetrical sections. This differentiation results in the complex nature of flow consequential from change with circular section of the billet on non-circular section of extrudate and various configuration of deformation zones (the size, shape and volume of plastic zone) to comparison with extrusion of axi- symmetrical cross- section extrudate.

Results

Conclusion