Ductibor® 1000 is one of the latest products in ArcelorMittal’s range of press hardenable steels (PHS) for hot stamping. Daimler, a global manufacturer of prestige vehicles, became one of the first carmakers to initiate an approval process for this extraordinary material. Depending on the results of that testing, Ductibor® 1000 may be used to form parts of a new Daimler vehicle.
Ductibor® 1000 offers carmakers a unique combination of high strength and good local crash ductility. In terms of mechanical properties, it’s a good fit between Usibor® 1500 and Ductibor® 500 and can be used in the same production processes. “The finely graduated strengths between these three grades allow OEMs to adjust and improve the function of the body-in-white (BIW) while potentially achieving significant weight savings at the same time,” notes Jean-Luc Thirion, head of ArcelorMittal’s Global R&D for Automotive.
With ArcelorMittal’s industry leading automotive steels available globally, OEMs can use existing hot stamping lines anywhere in the world. This allows carmakers to develop a vehicle in one location, then serially produce it locally, without major modifications to the local line’s furnaces or tooling. For a global OEM such as Daimler, this is a vital advantage.
Compared to AHSS for cold stamping, Ductibor® 1000 offers better formability and geometric accuracy, a feature of the hot stamping process explains Jean-Luc Thirion: “That enables carmakers to create parts which are not possible with cold stamped AHSS above 800 MPa. There is also less springback.”
Ductibor® 1000 can potentially increase the number of press hardened steel (PHS) parts used in today’s vehicles. For example, it could be a solution for energy absorption parts which must safely deform during the crash such as front and rear rails. “Depending on the formability and mechanical properties required for the specific part, Ductibor® 1000 can be an excellent choice,” says Jean-Luc Thirion. “Carmakers also have the possibility of combining Usibor® 1500 and Ductibor® 1000 in laser welded blanks.”
For many OEMs, weight saving potential is a critical assessment criterion when assessing new materials. The high strength of Ductibor® 1000 allows Daimler to minimise the thickness of parts, ensuring the part is significantly lighter. “Ductibor®1000 can also be a substitute for cold forming steels (such as micro-alloyed steels or DP grades) to optimise lightweighting opportunities,” notes Jean-Luc Thirion.
Daimler is assessing Ductibor® 1000 for parts which demand crash robustness at spot welds such as the B-pillar. But it is also suitable for parts which require high levels of local crash ductility such as longitudinal and cross members. Ductibor® 1000 can also be an extremely useful material to lightweight vehicles with a steel intensive or mixed-material body-in-white (BIW).
Jérôme Favero, ArcelorMittal’s resident engineer at Daimler
Since Ductibor® 1000 was released at the end of 2017, Daimler has been researching applications for this remarkable material. With the long model development cycles in the industry, it could still be a few years before production vehicles are using the new grade. But thanks to its unique combination of high strength and ductility, and the lightweighting opportunities it offers, there are likely to be some Daimler vehicles using Ductibor® 1000 on our roads.
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