scholarly journals An investigation of the Formability Behaviour of High Strength Aluminium Alloys Using Different Heat Assisted Forming Processes

2021 ◽  
Author(s):  
M. Schmiedt ◽  
J.M. Schlosser ◽  
R. Schneider ◽  
W. Rimkus ◽  
D.K. Harrison

The usage of ultra-high strength aluminium alloys (EN AW-7000 series) offers a great weight saving potential due to the high rigidity and specific strength values. Various heat assisted forming technologies have been developed in order to improve the limited formability at room temperature and thus to be able to increase the geometrical complexity of such sheet metal parts. In this study the forming behaviour of EN AW-7021 sheet metal alloy is described as a function of the forming process and the corresponding temperature profile. The forming limit curves (FLCs) are obtained by experimental Nakajima tests using the Warmforming, Hotforming, extended Hotforming and W-Temper process route. For this purpose, a Nakajima testing tool is designed according to ISO 12004 standard which allows operating temperatures of up to 200 °C.

Procedia CIRP ◽  
2014 ◽  
Vol 18 ◽  
pp. 203-208 ◽  
Author(s):  
J. Enz ◽  
S. Riekehr ◽  
V. Ventzke ◽  
N. Sotirov ◽  
N. Kashaev

2018 ◽  
Vol 108 (10) ◽  
pp. 639-645
Author(s):  
P. Groche ◽  
J. Günzel ◽  
T. Suckow

Zur Ausnutzung der hohen spezifischen Festigkeit und folglich Eignung als Leichtbauwerkstoff von EN AW-7075 bedarf es neben den Umform- auch Wärmebehandlungsprozessen, die im Folgenden in den Umformprozess integriert werden und die Prozesskette somit deutlich kürzer und effizienter gestalten. Dieser Fachbeitrag zeigt, welches Produktivitäts- und Leichtbaupotenzial durch eine Inline-Wärmebehandlung erschlossen werden kann.   To be able to exploit the high specific strength and thus suitability of EN AW-7075 as a lightweight construction material, it requires not only forming but also heat treatment processes. The latter become integrated into the forming process and thus make the process chain significantly shorter and more efficient. This paper points out the potential for productivity and lightweight construction to be tapped by inline heat treatment.


2005 ◽  
Vol 6-8 ◽  
pp. 771-778 ◽  
Author(s):  
M. Redecker ◽  
Karl Roll ◽  
S. Häussinger

In recent years very strong efforts have been undertaken to build light weight structures of car bodies in the automotive industry. Structural technologies like Space Frame, tailored blanks and relief-embossed panels are well-known and already in use. Beside that there is a large assortment of design materials with low density or high strength. Magnesium alloys are lighter by approximately 34 percent than aluminum alloys and are considered to be the lightest metallic design material. However forming processes of magnesium sheet metal are difficult due to its complex plasticity behavior. Strain rate sensitivity, asymmetric and softening yield behavior of magnesium are leading to a complex description of the forming process. Asymmetric yield behavior means different yield stress depending on tensile or compressive loading. It is well-known that elevated temperatures around 200°C improve the local flow behavior of magnesium. Experiments show that in this way the forming limit curves can be considerably increased. So far the simulation of the forming process including temperature, strain rates and plastic asymmetry is not state-of-the-art. Moreover, neither reliable material data nor standardized testing procedures are available. According to the great attractiveness of magnesium sheet metal parts there is a serious need for a reliable modeling of the virtual process chain including the specification of required mechanical properties. An existing series geometry which already can be made of magnesium at elevated temperatures is calculated using the finite element method. The results clarify the failings of standard calculation methods and show potentials of its improvement.


2006 ◽  
Vol 510-511 ◽  
pp. 330-333
Author(s):  
M.C. Curiel ◽  
Ho Sung Aum ◽  
Joaquín Lira-Olivares

Numerical simulations based on Finite Element Analysis (FEA) are widely used to predict and evaluate the forming parameters before performing the physical processes. In the sheet metal industry, there are basically two types of FE programs: the inverse (one-step) programs and the incremental programs. In the present paper, the forming process of the shield case piece (LTA260W1-L05) was optimized by performing simulations with both types of software. The main analyzed parameter was the blankholding force while the rest of the parameters were kept constant. The criteria used to determine the optimum value was based on the Forming Limit Diagram (FLD), fracture and wrinkling of the material, thickness distribution, and the principal strains obtained. It was found that the holding force during the forming process deeply affects the results, and a range of values was established in which the process is assumed to give a good quality piece.


2012 ◽  
Vol 706-709 ◽  
pp. 681-686 ◽  
Author(s):  
Heinz Palkowski ◽  
Olga Sokolova ◽  
Adele Carradò

High-performance metal/polymer/metal hybrid sandwich composites are attractive materials for lightweight constructions in automotive, aerospace and naval engineering world-wide. Due to the excellent combination of mechanical, thermal and elastic properties and, as a result of high forming potential, they can be used in areas of high vibration, where high damping properties of the polymer are demanded and at the same time high strength and stiffness are given by the metal. Disadvantages can be given in case of mechanical or thermal joining of these polymer-based sandwiches because of the elastic behaviour as well as low melting temperature of the polymer. Local metal plate insertions in the soft core at the place of joining can be a solution for such kind of problems. But forming behaviour of sandwich materials with and without local inlays differs strongly. Sandwich composites of that type were produced by roll-bonding. Their quality and their position were controlled by Lockin thermography. The forming behaviour of sandwiches with different geometry, size, type and the position of the inlays was tested by deep drawing and bending and analysed with the help of digital photogrammetry and compared to experimentally obtained mechanical properties. As a result, the local inlays, as well as their geometry, size and type strongly influence the forming limit conditions. The differences in flow behaviour of non-reinforced and reinforced sandwich regions after deep drawing and bending will be presented, as well as the influence of the position of the inlays.


2015 ◽  
Vol 809-810 ◽  
pp. 259-264
Author(s):  
Dan Chiorescu ◽  
Gheorghe Nagîț ◽  
Oana Dodun

Deep drawing is one of the most important processes for forming sheet metal parts. Besides its importance as a forming process, cup drawing also serves as a basic test for the sheet metal formability. This article investigates the influence of the die punch clearance, the average velocity in the active stage and the lubrication on the deep drawing quality expressed by the thickness evenness on the finished product surface. In order to minimize the number of experimental trials, a fractional factorial design was developed together with an orthogonal array, thus analyzing the contribution of the three parameters under study to the quality of the deep drawing process. Using TAGUCHI’s signal-to-noise ratio, we determine that ram velocity has a major influence, followed by the clearance between the active elements, while the contribution of lubrication is negligible. The results of the research are useful in developing a sensible design of experiments.


2015 ◽  
Vol 75 (8) ◽  
Author(s):  
Muhamad Sani Buang ◽  
Shahrul Azam Abdullah ◽  
Juri Saedon ◽  
Hashim Abdullah

Complex components of the sheet metal forming process need to be designed with high precision and accuracy in order to prevent defects and misalignment of the end products. One of the sheet metal cool stamping process for these complex automotive components is burring which is the forming of a flange around a hole made in a piece of sheet metal. Springback is a common defect during the burring process. The aims of this paper are to investigate the springback effect and improve shape accuracy of hole burring by inner burring process of lower arm part for automotive lower arm part. The springback defects at hole burring usually happened on the inner burring process. Experimental stretch flanging for cold stamping process of inner burring process was used to investigate the reasons of springback effect around the burred hole for a lower arm part of high strength steel (HSS) sheets SPFH590. From the two designs of burring punch dies, the result shows the values of springback effect for clearance -0.15 which have a big gap at hole burring A arm and B arm diameters, are larger than clearance -0.34 which have small gap for inner burring process of lower arm part. The experimental analysis shows that springback is proportionally related to the punch-die clearance parameter of the tool profile where the springback increase as the clearance increases. 


2005 ◽  
Vol 6-8 ◽  
pp. 457-464 ◽  
Author(s):  
L. Lamminen

Incremental sheet forming (ISF) has been a subject of research for many research groups before. However, all of the published results so far have been related to either commercial ISF machines or ISF forming with NC mills or similar. The research reported in this paper concentrates on incremental sheet forming with an industrial robot. The test equipment is based on a strong arm robot and a moving forming table, where a sheet metal blank is attached. The tool slides on the surface of the sheet and forms it incrementally to the desired shape. The robot is capable of 5-axis forming, which enables forming of inwards curved forms. In this paper the forming limit diagram (FLD) for ISF with the robot is presented and it is compared with conventional forming limit diagrams. It will be shown that the conventional FLD does not apply to incremental forming process. Geometrical accuracy of sample pieces is also studied. Cones of different shapes are formed with the robot equipment and their correspondence with the 3D CAD model is evaluated. The results are compared with other results of accuracy of incremental sheet forming, reported earlier by other researchers. The third issue covered in this article is a product development point of view to incremental sheet forming. In addition to fast prototyping and low volume production of sheet metal parts, ISF brings new possibilities to sheet metal component design and manufacturing. These possibilities can only be exploited if design rules, that will take the possibilities and limitations of the method into account are created for ISF.


Sign in / Sign up

Export Citation Format

Share Document