Production of Structure Components with Selective Properties by means of Action Media based Cold Forming

authored by: Bernd Arno Behrens, Thomas Hagen, Jens Mielke, Kanwar Bir Sidhu
Abstract: Minimising a metallic component's weight can be achieved by either using lightweight alloys or by improving the component's properties. In both cases, the material formability affects the utilisability for mass production processes. Most of the high-strength materials show a material-restricted formability and are difficult to forge. The formability of a material is described by its maximum forming limit. Large plastic strains can lead to mechanical damage within the material. A promising approach of handling low ductile, high-strength alloys in a forming process is deformation under superimposed hydrostatic pressure by active media. In the present study, the influence of superimposed hydrostatic pressure on the flow stress is analysed as well as the forming ability for different sample geometries at different hydrostatic pressure and temperature levels. The experimental results show that the superimposed pressure has no influence on the plastic deformation, nor does a pressure dependent near-surface material hardening occur. Nevertheless, the formability is improved with increasing hydrostatic pressure. The relative gain at room temperature and increase in the superimposed pressure from 0 bar to 600 bar for tested materials was at least 140 % and max. 220 %. Therefore, a cold forming process under superimposed pressure is developed to produce structure components with selective properties. For example, the gain in formability will be used to enlarge local plastic strains to higher limits resulting in higher local strain hardening and hardness. This offers new design possibilities with selectively adjusted local structure or structure component properties, especially adapted to their technical application. Additionally, by applying damage models, finite-element analysis is used in order to predict damage occurring in the cold forming process under superimposed hydrostatic pressure for various sample geometries.
Organisation(s): Institute of Metal Forming and Metal Forming Machines
Type: Article
Journal: Steel research international
Volume: 79
Pages: 233-239
No. of pages: 7
ISSN: 1611-3683
Publication date: 03.2008
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Condensed Matter Physics, Physical and Theoretical Chemistry, Metals and Alloys, Materials Chemistry
Electronic version(s): https://doi.org/10.2374/SRI07SP122-79-2008-233-239 (Access: Closed)
https://doi.org/10.1002/srin.200806346 (Access: Closed)
: Details in the research portal "Research@Leibniz University"

BibTeX

@article{0b5cc8e587d240e29421bf63aec07c4b,
title = "Production of Structure Components with Selective Properties by means of Action Media based Cold Forming",
abstract = "Minimising a metallic component's weight can be achieved by either using lightweight alloys or by improving the component's properties. In both cases, the material formability affects the utilisability for mass production processes. Most of the high-strength materials show a material-restricted formability and are difficult to forge. The formability of a material is described by its maximum forming limit. Large plastic strains can lead to mechanical damage within the material. A promising approach of handling low ductile, high-strength alloys in a forming process is deformation under superimposed hydrostatic pressure by active media. In the present study, the influence of superimposed hydrostatic pressure on the flow stress is analysed as well as the forming ability for different sample geometries at different hydrostatic pressure and temperature levels. The experimental results show that the superimposed pressure has no influence on the plastic deformation, nor does a pressure dependent near-surface material hardening occur. Nevertheless, the formability is improved with increasing hydrostatic pressure. The relative gain at room temperature and increase in the superimposed pressure from 0 bar to 600 bar for tested materials was at least 140 % and max. 220 %. Therefore, a cold forming process under superimposed pressure is developed to produce structure components with selective properties. For example, the gain in formability will be used to enlarge local plastic strains to higher limits resulting in higher local strain hardening and hardness. This offers new design possibilities with selectively adjusted local structure or structure component properties, especially adapted to their technical application. Additionally, by applying damage models, finite-element analysis is used in order to predict damage occurring in the cold forming process under superimposed hydrostatic pressure for various sample geometries.",
keywords = "Active means, Cold forming, Damage models, Extrusion, Increase in formability, Lemaitre model, Strain hardening, Superimposed hydrostatic pressure, Upsetting",
author = "Behrens, {Bernd Arno} and Thomas Hagen and Jens Mielke and Sidhu, {Kanwar Bir}",
year = "2008",
month = mar,
doi = "10.2374/SRI07SP122-79-2008-233-239",
language = "English",
volume = "79",
pages = "233--239",
journal = "Steel research international",
issn = "1611-3683",
publisher = "Wiley-Blackwell",
number = "3",
}