Investigation of metal flow in bridge die extrusion of Alloy 6063 and subsequent effect on surface quality and weld seam integrity

Abstract

This paper describes a detailed study of tube extrusion by simulation using finite element method (FEM). The finite element model used one-sixth of symmetry. The extrusion load, temperature evolution and metal flow were predicted. Innovative methods, combining both grid and surface tools, were used to define in detail the flow of material. These showed clearly the inner and outer surface formation mechanisms of the tube extrusion. The seam weld, an important quality indicator, was also evaluated by selecting an appropriate criterion.

Simulation Analysis of Porthole Die Extrusion Process and Die Structure Modifications for an Aluminum Profile with High Length–Width Ratio and Small Cavity

“…The quality of weld seams is an important quality index for evaluating hollow aluminum profiles. Adhesive bonding under pressure plays a dominant role in the solid-state welding of the seams [ 6 , 25 , 26 ]. In recent years, the issue of longitudinal welding has attracted lots of interest from researchers, and several criteria were proposed for evaluating its quality, such as the maximum pressure criterion [ 27 ], pressure-time-flow criterion [ 28 ], and pressure-time-temperature-strain rate criterion [ 29 ].…”

Micro-structural Evolution in Metals Subjected to Simple Shear by a Particular Severe Plastic Deformation Method

“…Extrusion, as one of the most widespread severe plastic deformation (SPD) methods, is of significant advantage in realizing large amounts of plastic deformation as well as improving production quality and performance but with high energy consumption and poor uniformity ( Ref 18,19). Gronostajski et al (Ref 20) have found that imposing torque on a die can significantly increase the shear strain of billet during extrusion to eliminate non-uniformity, improve the mechanical properties, and obtain a dense microstructure.…”

Microstructural and X-ray tomographic analysis of damage in extruded aluminium weld seams

“…The formation of weld seams and the influence of processing conditions on weld seam properties have been addressed in several recent articles. [5][6][7][8][9][10][11][12][13][14][15] These analyses focussed on characterising the flow behaviour of the aluminium as this travels from the container through the die. Flow patterns, generated by sectioning samples from extrusions originating from model materials such as plasticine 5,6 or specially prepared composite aluminium billets consisting of alloys giving a different etching response, [7][8][9][10] were related to geometrical features of the tooling.…”

“…Often numerical techniques are utilised to calculate local conditions in the extrusion tooling, resulting in a conclusion concerning the weld seam quality. Many of these methods treat the extruded material as a microstructure free continuum and centre on a mechanical interpretation of the solid state bonding process, that is, for achieving an adequate level of pressure on the welding plane during transition of the material through the tooling, as described by Bourqui et al 11 , Gasiorczyk and Richert 12 and Plata and Piwnik 13 in a comprehensive review by Donati and Tomesani 14 and more recently by Sheppard et al 15 through the application of the Oyane damage parameter implemented in the finite element code Forge TM . For specific well defined conditions, these studies have led to semi-empirical formulations, correlating weld seam properties to conditions in the extrusion die.…”