Docol complex phase steels: superior edge ductility, stretch-flangeability and formability

Docol® complex phase steels offer improved formability and hole expansion ratios for superior resistance to edge cracking. They are ideal for challenging, crash-relevant automotive components with complex designs on shear stretched edges.

    Main characteristics of Docol complex phase steel

    • Very high hole expansion ratios (stretch flangeability) for resistance to edge cracking.
    • Improved cleanliness provides excellent edge ductility and tight radii bendability.
    • Excellent for fineblanking and energy-efficient cold-forming of automotive parts with complex edges.
    • Can significantly reduce or eliminate micro cracks and burrs on cut/sheared edges.
    • Greatly increased local formability, providing ductility for deep-drawn components with complex geometries.

    Meet our new Docol® hot-rolled 800MPa CP steels

    To form or stretch cut edges that are crack-free can be a major challenge when working with advanced-high strength steels. To reduce the risk of cracked (raised) edges, SSAB is introducing three new versions of hot-rolled 800 megapascal steels grades with extremely high edge ductility.

    Many of these steel properties should contradict one another: formability vs. high strength, high edge ductility vs. good crash performance. But these steels deliver all of these properties — and, especially, they deliver very high edge ductility.

    These new high edge ductility AHSSs can step in as “problem-solvers.” Or, they can be used on auto parts where you want higher confidence that you won’t have cracked edges.

    Control arm
    Docol HR800CP+HER

    70% typical HER

    Our latest complex phase steels include our newly improved Docol® HR800CP and the new HR800CP+HER (the +HER means we test every shipment to guarantee a minimum hole expansion ratio).

    Docol HR800 HE

    100% typical hole expansion ratio

    All of our new hot-rolled 800HE, steel is HER tested to guarantee extremely high edge ductility.

    Applications for Docol® complex phase steels

    Hot-rolled Docol CP steels deliver good fatigue properties and can therefore be good for parts that are constantly moving and shaking. For example, multilink suspensions, trailing arms, torsion beams and subframes.

    Cold-rolled Docol CP applications include body-in-white applications, seat tracks and seat recliners.

    Body in white

    Grades and mechanical properties for Docol complex phase steel

    For best weight reduction, use high grades with reduced thicknesses.

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      Docol 600CP GI, GA, ZA T: 0.7– 2.5 mm
      W: Up to 1520 mm
      Docol 800CP UC, GI, GA, ZA T: 0.5–4 mm
      W: W: Up to 1530 mm
      Docol 1000CP UC, EG, GI T: 0.5–2.1 mm
      W: Up to 1530 mm
      Docol 1200CP UC T: 1–1.8 mm VDA239-100:2016
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        Forming Docol complex phase steel

        • Outstanding ISO hole expansion ratios allows stretch flanging and stretch bending, as well as punched flanges, without edge cracking.
        • Improved cleanliness allows deep drawing and tight radius forming.
        • With exceptional bending properties and formability, these steels are suitable for cold forming of critical auto safety components.
        • Excellent for both stamping and roll forming.
        • Ideal for fineblanking.
        • Good weldability, including resistance spot welding.

        Do you have manufacturability questions about these grades? Our Technical Support can provide specific CP and HE steel forming guidance for your automotive component.


        Forming Docol Complex Phase steel

        Additional benefits from Docol complex phase steel

        • Good fatigue properties for all vehicles: ICE, hybrid, or BEV.

        • Additional customized grades are available to meet OEM-specific certifications. 
        • Corrosion resistance coatings available on all complex phase grades.

        • Global availability and support.

        • Lean C-Mn base composition.

        • Excellent uniform ductility (see our article about elongation).

        • Bake-hardenable.

        OEM-specific complex phase steels

        Docol CP steels are made according to VDA, EN, SSAB and OEM specifications.

        The benefits of Docol CP steel for each team member

        Safety engineers: Specify AHSS, UHSS, or gigapascal complex phase and high edge steels for high-performance energy-absorption in passive safety systems.

        Lightweighting engineers: Achieve thinner and lighter parts by specifying higher strength grades of CP steels.

        Production engineers: Deliver complex shape components – e.g., stretched flanges with punched holes and tight radii – with high repeatability. Fully leverage cold-forming operations to save energy and processing time while increasing production line flexibility.

        Procurement officers: Buy less material as you greatly reduce the number of defective components due to cracked sheared edges.

        Sustainability officers: Substantially lower the embedded CO2 in your critical safety components by replacing aluminum and CFRPs. SSAB’s iron-ore based steelmaking is so CO2-efficient that our steels are equivalent to using recycled steel.

        Lower your embedded CO2

        Docol complex phase steels are “future proofed”.


        Try it for yourself

        With our Trial Material Stock Center, you can get AHSS samples for any of our commercially available steels – as well as samples for our newest but not yet commercially released grades. Unique to the industry, we ship coils, sheets and custom lengths of any size. In 1 to 2 weeks, your material is ready for dispatch to anywhere in the world.