University of Oulu

Anna-Maija Arola, Antti Kaijalainen, Vili Kesti, Lars Troive, Jari Larkiola, David Porter, The effect of mechanical behavior on bendability of ultrahigh-strength steel, Materials Today Communications, Volume 26, 2021, 101943, ISSN 2352-4928,

The effect of mechanical behavior on bendability of ultrahigh-strength steel

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Author: Arola, Anna-Maija1; Kaijalainen, Antti1; Kesti, Vili2;
Organizations: 1University of Oulu, Materials and Mechanical Engineering, Centre for Advanced Steel Research, P.O. Box 4200, FI-90014, Oulu, Finland
2SSAB Europe Oy, Rautaruukintie 155, 92101, Raahe, Finland
3SSAB Borlänge, Brygga 53, 78184, Borlänge, Sverige, Sweden
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 13.4 MB)
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Language: English
Published: Elsevier, 2021
Publish Date: 2020-12-22


Bendability is an important property of ultrahigh-strength steels since the typical applications of such materials include structures manufactured by air-bending. Conventional methods to evaluate bendability, such as the bending test according to the standard VDA-238 or the conventional tensile test do not provide sufficient information to evaluate bendability of ultrahigh-strength steels due to the average nature of the material response in these tests. In this study, the mechanical properties were determined using thin tensile specimens cut from the surface of the sheet and the evaluation of bendability was carried out using frictionless bending tests. The results of the experiments and FE-modelling presented in this paper reveal that the mechanical properties of the sheet surface have a significant impact on bendability. Novel ultrahigh-strength steel with better work-hardening capacity at the surface caused by a layer of relatively soft ferrite and lower bainite has good bendability, especially when the bend line is aligned transverse to the rolling direction. Microstructural investigations reveal that in a conventional steel with a relatively hard surface microstructure, the deformation localizes into shear bands that eventually lead to fracture, but similar shear banding was not present in the novel steel surface. This can be attributed to the better work-hardening capacity which delays the onset of shear localization and fracture.

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Series: Materials today communications
ISSN: 2352-4928
ISSN-E: 2352-4928
ISSN-L: 2352-4928
Volume: 26
Article number: 101943
DOI: 10.1016/j.mtcomm.2020.101943
Type of Publication: A1 Journal article – refereed
Field of Science: 216 Materials engineering
Funding: The authors would like to acknowledge the funding through project Flexible and Adaptive Operation in Metal production (FLEX, 2017-2019) from Business Finland and DIMECC.
Copyright information: © 2020 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (