Seat crossmember

Dual-phase steel - Seat crossmember

Steels are increasingly utilized in new vehicle generations, which require both high strength and good formability. Dual-phase steels meet this objective particularly well.

Thanks to a component-appropriate design and a reduction of the material thickness, this new generation of materials makes considerable contributions to lightweight automotive engineering and construction.

Dual-phase steel

Dual phase steels feature comparatively low yield strengths and are consequently easy to form. Due to their extremely high work hardening level, they are particularly suitable for use in crash-relevant components.

Foto von einem Kotflügel aus Dualphasen-Stahl

Component: Seat crossmember VW PQ 35

For a seat crossmember, a feasibility study was carried out in cooperation with Volkswagen AG on the use of dual-phase steel. By replacing the series material CR340LA-GI with a hot-dip galvanized dual-phase steel (CR330Y590T-DP-GI), a sheet thickness reduction of 0.23 mm was achieved.

This results in a weight savings of 19% or approximately 280g per part. The overall weight of the vehicle was consequently reduced by 0.560 kg in mass.

Component:Seat crossmember
Series material:CR380LA+GI
Sheet thickness:1.23 mm (series), 1.00 mm (reduced)


Hot-dipped-galvanized (Z100)

Weight savings:

19 % per component compared to series component

Material characteristics:

Reduced edge cracking susceptibility, proven by increased hole expansion capacity (High Hole Expansion = HHE)

Reduced carbon equivalent for improving the failure behavior of the weld seam (C ≤ 0.1 by weight %)

ST 1 =micro-alloyed material (e.g., niobium or niobium + boron + titanium)

ST 2 = silicon-alloyed material


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