https://popups.uliege.be/esaform21/index.php?id=78 Coordinator: Dr. Soeren Müller Co-Organisers: Prof. Wociech Z. Misiolek, Prof. André L. Costa Description: Contributions that cover all aspects of the technology of drawing and extrusion of metals are welcomed to this mini-symposium; literature reviews, experimental and theoretical work on the mechanics and the metallurgical aspects of extrusion and drawing of various metals, FE-analysis of such processes to calculate forming parameters as well as the resulting microstructure and the mechanical properties of the products fabricated by means of drawing or extrusion. Technological testing and the mechanics of such test where the purpose is to collect material or processing data for describing of such processes are also included. Mini Symposia fr Wed, 03 Mar 2021 09:33:15 +0100 Wed, 14 Apr 2021 09:52:51 +0200 https://popups.uliege.be/esaform21/index.php?id=78 0 https://popups.uliege.be/esaform21/index.php?id=3605 The study assesses feasibility of hot extrusion of a large seamless hexagonal 9%Cr-1%Mo steel tube. The manufacturing chain starts from a pierced cylindrical billet, hot extruded and to be further cold drawn in several passes. Preliminary industrial tests have shown thickness reduction in extrusion limited by a huge initial force peak (+25 %) reaching the press capacity. To understand this force peak, thermomechanical numerical simulation (ForgeNxt®) of the furnace-press transfer and extrusion stages is carried out. Constitutive model at high temperature, high strain and strain rate has been selected from literature. Surface properties, namely Heat Transfer Coefficient (HTC) and friction coefficient, have been made space- and time-dependent to represent glass lubrication. Numerical results are qualitatively compared to industrial experimental values to evaluate the prediction of the model. It suggests that the difficult start of the glass melting and flow along a cooled die affects the force peak. Practical improvements are suggested on this basis, together with possible refinements of the simulation for more precision and insight into extruded tube quality. Mon, 29 Mar 2021 13:33:17 +0200 https://popups.uliege.be/esaform21/index.php?id=3605 https://popups.uliege.be/esaform21/index.php?id=3686 Liquid nitrogen cooling is widely used in the extrusion industrial practice in order to increase the production rate, to reduce the die temperature and to avoid defects on the profile exit surfaces resulting from an excessive heating. However, the efficiency of the cooling is deeply affected by position and design of the liquid nitrogen channel so that numerical modelling is gaining an increasing industrial interest in relation to the possibility offered to optimize the channel design without expensive and time-consuming experimental trials. In this work, a numerical FE model developed within COMSOL Multiphysics® is proposed and validated against experimental trials performed in industrial environment. The model combines the 3D simulation of the extrusion process with a 1D model of the cooling channel thus allowing the testing of a number of different solutions at the die design stage. The global aim of this work is the assessment of the liquid nitrogen cooling efficiency in the extrusion of an industrial aluminum profile and the proof of the potentials offered by numerical models to get an optimized channel design in terms of cooling efficiency, die thermal balancing and reduction of liquid nitrogen consumption. Mon, 29 Mar 2021 14:11:19 +0200 https://popups.uliege.be/esaform21/index.php?id=3686 https://popups.uliege.be/esaform21/index.php?id=3714 Since its first synthesis in 2004 graphene was characterized intensively and exceptional properties in terms of e.g. mechanical strength, stiffness and electrical as well as thermal conductivity were revealed. These properties make graphene very attractive to be applied as additive in composite materials e.g. to increase strength and conductivity compared to the pure matrix material. In this study graphene nano platelets (GNP) in contents of 0. 5%, 1.0 % and 1.5 % were added to pure (99.7 %) aluminum powder and dispersed via EIRICH mixer method. This method is very appealing since homogenous mixtures can be achieved in significantly lower time when compared to e.g. the ball milling process. After subsequent cold compaction the composite materials were extruded with three different extrusion ratios. The influence of GNP content and extrusion ratio on the specific extrusion pressure is characterized as well the resulting rod surface quality, respectively. The effects of GNP content and extrusion ratio on homogeneity of graphene dispersion in the aluminum matrix, the relative density of the composite as well as hardness were also investigated. Mon, 29 Mar 2021 14:18:38 +0200 https://popups.uliege.be/esaform21/index.php?id=3714 https://popups.uliege.be/esaform21/index.php?id=4785 In copper extrusion, billet temperatures of 600°C or more are very common and the dies are therefore exposed to high thermo-mechanical stress. This causes deflection and wear of the dies and thus reduced quality of the extruded profile. In the present study, die deflection and residual deformation after several extrusion cycles was investigated by means of extrusion trials and numerical analyses. Material models of four tool materials (hot-work tool steels 1.2367 and CS1, nickel-based alloy 718, cobalt-based alloy Stellite 1) and the copper alloy CW024A were provided by hot compression tests. Extrusion trials were carried out applying four different dies, each made of another tool material. Using the FEM based software DEFORM 2D, the extrusion trials were modeled and decoupled die stress analyses were performed, which simulated three consecutive load cycles. The focus of the data interpretation was in die deflection in proximity of the die land due to the thermo-mechanical load and residual plastic deformation after relief of the mechanical load. Larger values of deflection close to the die land were observed for the hot-work tool steels, while the deflection of nickel- and cobalt-based alloys was negligibly small. Also, remarkable plastic deformation was only determined for the hot-work tool steels, with increasing values for every simulated load cycle. This analysis characterizes the performance limits of hot-work tool steels and the benefits of nickel- and cobalt-based alloys regarding contour accuracy during high temperature copper extrusion. Fri, 09 Apr 2021 10:12:11 +0200 https://popups.uliege.be/esaform21/index.php?id=4785