13th International Conference on the Technology of Plasticity (ICTP 2021): Extrusion and Drawing
Program Organizers: Glenn Daehn, Ohio State University; Libby Culley, The Ohio State University; Anupam Vivek, Ohio State University; Jian Cao, Northwestern University; Brad Kinsey, University of New Hampshire; Erman Tekkaya, TU Dortmund; Yoshinori Yoshida, Gifu University
Thursday 10:20 AM
July 29, 2021
Room: Virtual: Room D
Location: Virtual
Session Chair: Daniel Cooper, University Of Michigan
Introduction of a New Method for Continuous Aluminum Hot Extrusion: Johannes Gebhard1; Patrick Kotzyba1; Oliver Hering1; A. Erman Tekkaya1; 1Institute of Forming Technology and Lightweight Components, Technische Universität Dortmund
The new extrusion process combines the conventional methods of direct and indirect aluminum hot extrusion by an innovative container and die setup with a moving or stationary valve. The process enables the continuous extrusion of aluminum profiles without any interruptions. With both variants, moving or stationary valve, the usual dead cycle times can be used for a continuous extrusion process. Furthermore, due to the continued material flow, a stationary profile exit temperature can be achieved, which leads to constant material properties. As up to now, a continuous extrusion press for aluminum is not available. The new process concept is analyzed on the basis of scaled experimental models using the model material plasticine and numerical simulations. The similarity of the model material was validated by aluminum extrusion experiments. Various model material colors were investigated, and the resulting material flow and process forces of the new process were analyzed.
Investigation of Forward–Backward-Radial Extrusion Process of Aluminum Alloy Wheel Hub: Qiang Wang1; Mu Meng1; Xubin Li1; Zhimin Zhang1; 1North University of China
As a kind of extrusion process, the Forward-Backward-Radial Extrusion (FBRE) process can be used to produce complex shaped parts with hoop protrusions or flanges. The control of metal flow is the key to affect forming, strain distribution and forming load of parts during FBRE process. On the basis of summarizing research of FBRE process, this paper presents the numerical and experimental results of aluminum alloy hub production using this method. Material flow behavior, strain distribution and strain heterogeneity within the final product was investigated by finite element methods. The parameters such as billet size, die corner radius and friction conditions are optimized and determined to control the material flow in different regions. While the uniformity of extrusion deformation is greatly improved, the extrusion forming load is reduced, and the aluminum alloy hub was manufactured by FBRE process. The comparison between the theoretical and the experimental results show good agreement.
Co-extrusion of Compound-cast AA7075/6060 Bilayer Billets at Various Temperatures: Hui Chen1; Danai Giannopoulou2; Thomas Greß3; Tim Mittler3; Jonas Isakovic2; Wolfram Volk3; Noomane Ben Khalifa1; 1Leuphana University of Lüneburg; 2Helmholtz-Zentrum Geesthacht; 3Technical University of Munich
Combination of dissimilar AA7075/6060 aluminum alloys benefits the advantages of high strength and good corrosion resistant in one hybrid component. Static compound-casting using appropriate casting conditions can achieve intermetallic bonding at the interface of the core AA7075 and sleeve AA6060. The inhomogeneous bonding due to non-uniform thermal conditions during static compound-casting can be eliminated by the following co-extrusion procedure. Direction hot extrusion of compound-cast AA7075/6060 bilayer billets at temperature of 420°C, 450°C and 480°C are conducted to analysis the influence of extrusion temperature on the interfacial bonding. The evolution of the interfacial bonding properties at different extrusion temperatures comparing with as-cast billets are depicted by light optical metallography and mechanical push-out test.
Reducing Aluminum Extrusion Transverse Weld Process Scrap: Gregory Oberhausen1; Anselm Christopher1; Daniel Cooper1; 1University of Michigan
Nearly 20% of the aluminum produced globally is extruded. Up to one-quarter of this aluminum is scrapped in the form of extrusion butts and segments of extruded profiles that contain weak solid-state “transverse” welds that are created between consecutively extruded billets in direct extrusion. In this article, extrusion of differently colored clay billets is used to conduct a parametric study on the effect of extrusion ratio, die angle, friction coefficient, profile shape, and dummy block profile on the transverse weld length. Shorter transverse weld lengths require smaller lengths of the extruded profile to be extracted and scrapped. The results show that the transverse weld length can be reduced by decreasing the extrusion ratio, die angle, or friction coefficient. The profile shape also has a strong influence; the transverse weld length was found to scale with the cross-sectional perimeter to area ratio of the extruded profile. Additionally, it is shown that the dummy block profile (a previously unexplored design variable) can be modified to decrease the weld length. A concave dummy block was designed using an estimated velocity field for axisymmetric extrusion of solid rods, decreasing the weld length by 44%. The industry implications of this work and the need for further research are discussed.
Study on Complex Extrusion of Multi Billets: Evaluation of Mechanical Properties of Butt-joined Products and Analysis of Joining State: Michihiko Hoshino1; Izuru Otake1; 1Nihon University
In recent years, an aluminum double skin panel, which has a complicated and wide cross- sectional shape and is manufactured by extrusion is used for railway vehicles. It is difficult to manufacture a double skin panel exceeding 600 mm width in the current forward extrusion process. However, from the viewpoint of weight saving, there is a demand to make double skin panel with larger width. So it is proposed to manufacture double skin panel with complex extrusion of multi billets. Complex extrusion of multi billets is suitable for producing complicated and wide extruded shape. And the joint part of the double skin panel is joined in a plate shape. In this study, industrial pure aluminum A1050 and representative extruded aluminum alloy A6063 were extruded into a plate shape, and the joining state was evaluated by tensile test, micro Vickers hardness test, microscopic observation and numerical analysis.
Effect of Expansion Ratio on Formability in Tube Drawing with Diameter Expansion: Hikaru Kawaguchi1; Shohei Kajikawa1; Takashi Kuboki1; Isamu Akasaka2; Yuzo Terashita2; Masayoshi Akiyama3; 1The University of Electro-Communications; 2Miyazaki Machinery Systems Co., Ltd.; 3Akiyama Mechanical Engineering Consulting
The conventional tube drawing has the disadvantages that thickness reduction in one pass is small. As a method to eliminate this disadvantage, tube drawing with diameter expansion was proposed in this study. At first, the tube is flared by pushing the plug into the tube end. After that, the plug is drawn with chucking the flared end, and the entire tube is expanded. Tensile circumferential and axial stress reduce the tube thickness effectively during the plug drawing. In this study, effect of expansion ratio on formability, such as thickness reduction and dimensional accuracy, was investigated by experiments and finite element analyses (FEA) for verifying effectiveness of the proposed method. As a result, the thickness reduction ratio increased with an increase in the expansion ratio, and the maximum thickness reduction ratio was 0.3 when an aluminum alloy of A1070 was used. Furthermore, deformation mechanism was considered by FEA.