The fracture resistance database, developed in the frame of the European ToughSteel project, aims at helping steel producers to position their products regarding existing ones and at accelerating the design of new alloys and of parts design by anticipating forming problems.
The essential work of fracture methodology has been recently introduced in the steel industry. The determination of the essential work of fracture data is simple but requires many specimens. Classical fracture toughness tests in the context of fracture mechanics require less samples but more complex testing methods. The availability of such data will accelerate the development of new products and will help sheet producers to increase their competitiveness. This is why an online open access database has been developed to gather existing information about thin metal sheet fracture data. The usefulness of this database can be even more important if each actor, i.e. industrials as well as academics, makes it living by continuously feeding it from the latest characterization and developments. This will moreover ensure that the database benefits last over time.
The goal of this database is twofold: it will gather the existing mine of results in a unique open access repository and it aims to be a tool able to highlight factors affecting fracture toughness, e.g. sheet thickness or material fracture strain, and that, for different classes of steels and metals. The database is accessible on the webpage https://sites.uclouvain.be/toughsteel/index.php after creating an account and can be used as a consultation tool or can be fed through the Encode tab.
“The scientific database is a unique opportunity for all thin products actors to position their products among the existing ones. Also, it highlights correlations between classical material properties, microstructure and fracture toughness which will help pushing forwards the development of innovative products with improved performances while understanding the physical mechanisms taking place.”, adds Thomas Pardoen, Professor at the Institute of Mechanics, Materials and Civil Engineering at UCLouvain, Belgium.
Crack related phenomena appearing during cold forming of thin metal sheets are limiting the use and development of new advanced high strength steels in the industry. The fracture and ductility criteria obtained through tensile tests and forming limit diagrams are not anymore sufficient for these innovative alloys showing the need to define new relevant criteria ensuring their good formability. The scientific community has demonstrated that fracture toughness is a good indicator of sheet performance regarding edge cracking and crashworthiness. The direct benefits of a better control of the formability are manyfold: decrease of production losses, reduction of the time-to-market and better material selection.
More specifically, the essential work of fracture methodology has proved to be an efficient experimental way to accurately measure sheet toughness using simple, fast and reliable tests without needing complex machining of test specimens.
“The essential work of fracture methodology brought us a new way to characterize the resistance to crack propagation during hot rolling. It appeared to be much more efficient than classical hot ductility tests to evaluate the influence of microstructure on the fracture process and derive relevant material properties.” states the Scientific Director of Aperam Stainless Europe, Jean-Denis Mithieux.
The ToughSteel project (RFCS European program, https://toughsteel.eu/), that funds the technical and human resources necessary to develop the database, involves and engages the main actors of the sheet metal forming community with the objective to promote, disseminate and transfer the know-how acquired about the use of fracture toughness as a tool to address cracking problems in forming and in-service performance of Advanced High Strength Steels.
ToughSteel consortium is formed by Eurecat, which coordinates and participates in the project through the Metallic and Ceramic Materials Unit and the Communication and Digital Marketing Unit, together with Luleå Tekniska Universitet, the catholic University of Louvain, Centro Ricerche Fiat, the Jernkontoret, UNESID – Unión de Empresas Siderúrgicas and UNE as a standardisation organism.