When it comes to chassis components, many have design properties that are in the range where hot rolled steel is more suitable than cold rolled steel. One of the biggest reasons for this is thickness. Cold rolled steels are generally only available with thicknesses from 0.5 mm to 2.1 mm, whereas hot rolled steel products go beyond, from 2.0 up to 6.0 mm.
“In addition to a wide thickness range, Docol® hot rolled AHSS makes it possible to drastically increase the tensile strength in a component, while reducing the amount of material needed to produce it. This can result in a significant reduction in weight, while achieving the same performance and a lower cost, thanks to less material needed overall,” explains Daniel Sund, Product Manager Hot Rolled Products, SSAB.
More than weight savings
However, the advantages of utilizing high strength hot rolled steel for chassis components like torsion beams, control arms and chassis frames goes further.
“Young’s model is high for steel, and in combination with good formability, you can reach high stiffness in components. High tensile strength and an optimized microstructure also give excellent fatigue properties. You also have good forming properties of hot rolled steels. Strength levels up to 1200 MPa are available, which is 4 times higher than high strength aluminum and steel is also the most cost efficient light weight material. Overall, the complexity and high integration level that chassis require today can be solved with steel,” says Sund.
The Docol® hot rolled offering
In 2011, SSAB invested in a new cooling line for its hot rolling mill. This state-of-the-art system resulted in the ability to create many more grades of hot rolled AHSS, with high consistency.
“The cooling line gives us both cooling power and the accuracy to hit the exact properties that we wish. As a result, SSAB can produce a wider range of steels than many other manufactures. Many years of adjusting and improving our hot rolled processes have led to a reputation as a quality producer,” explains Sund.
The range of Docol® hot rolled steels is extensive, with many more grades currently in development, including steels like complex phase (CP), martensitic steel (M), press hardening steels (PHS) as well as grades with improved hole expansion and the new 3rd generations steels. Each can provide characteristics that are interesting for chassis applications.
All Docol® grades are also combined with close collaboration and advice from SSAB. When choosing a high strength material, it is important to maximize the properties of the material in the right way and SSAB can offer assistance in everything from simple questions to joint development projects.
With Docol® hot rolled AHSS chassis component manufacturers will find innovative design and process solutions, which will allow for achieving improved properties such as weight savings, improved performance and reductions in costs.