Innovative thin dual-phase steels for outer skin applications

17.07.2024 | Salzgitter Flachstahl GmbH


Lightweight design and construction remains one of the driving topics in automotive engineering. In addition to aluminum, steel concepts entailing soft deep-drawing steels (IF - interstitial free) or bake-hardening steels (BH) are predominately finding use in automotive outer skins. These materials can be appropriately substituted by the use of thin dual-phase (DP) steels with a thickness range of less than or equal to 0.6 mm, thereby opening up a high lightweight engineering potential of up to 17%. Special application areas may include doors and flaps, fenders or even the roof. Thanks to these weight savings CO2-emissions can be reduced both in the production and in the utilization phase.

 

Dual-phase steels are also characterized by their good formability and high strength. They also combine their outstanding work hardening properties with bake-
hardening potential. Thanks to the virtually isotropic properties, the position of the component in the sheet can be rotated as required without any restrictions on use.
 
Since 2020, Salzgitter Flachstahl, as a reliable partner, has already supplied automotive customers with more than 10,000 tons of this highly innovative material for various outer skin applications.

The mechanical-technological characteristic values are indicated in the following table:

Yield Strength Tensile Strength Elongation at break n-value
Steel grade Rp0,2 [Mpa]* Rm [Mpa]* A80 [%] n10-20/Ag*
CR250Y440T-DP 250 - 330 440 - 560 ≥ 27 ≥ 0,16
CR290Y490T-DP 290 - 380 490 - 600 ≥ 24 ≥ 0,15

Salzgitter Flachstahl's dual-phase steels in outer skin quality are available in the following dimensions:

  • Thickness from 0.50 to 0.90 mm
  • Width from 1,000 to 1,500 mm

Other dimensions outside this range can also be provided on request.  
The advantages of thin dual-phase steels for outer skin applications can be summarized as follows:

  • Saving resources thanks to reduced material requirements
  • Weight reductions of up to 17 % for outer skin applications (based on a mudguard made of CR180BH, for example)
  • Free choice of component position in the sheet due to the material’s quasi-isotropic properties

If you would like more detailed information on the potential uses of thin dual-phase steels in the outer skin area, your contacts at the technical customer service and sales department will be happy to help.