Dual phase with high formability/ductility for crack-free cold deep drawing

Dual phase steels with high formability (DH) use a multiphase microstructure with a ferrite matrix holding martensite, bainite and retained austenite. Unlike conventional dual phase steels, DH steel’s hardening rate persists at higher strains levels. This is because DH’s larger quantity of retained austenite is transformed into martensite at a progressively increasing rate of work hardening under higher strains.

With its substantially higher strain hardening rate (n-value), TRIP-assisted 3rd Gen steels like DH provide distinctly improved formability in stretch deformation compared to DP grades. TRIP-assisted DH steels provide high ductility for manufacturing automotive safety components with complex geometries. Plus DH steels supply superb and progressive crash-energy absorption — via high strain hardening — during crash deformation.

• High global and local formability, with higher elongation and higher resistance to edge cracking than conventional DP.
• Stellar crash performance, with ductility left in the steel for additional energy absorption.
• Greater design flexibility: enables deep drawing of complex geometries with secondary forming.
• Highly resistant to compression failure.
• UHSS strength levels with improved FLD and HER performance compared to conventional DP.
• 3rd Gen AHSS allows for simplified, cost-effective, cold forming of complex auto parts.
• Very good RSW weldability, comparable to conventional DP grades.
• Enables lighter, more complex BIW components — with less risk of edge cracking compared to DP.