Following the successful trials of its XPF product range, Tata Steel has now commercially launched XPF800 — a new hot-rolled steel for demanding chassis applications.
This offers “an unprecedented mix” of strength and formability, which gives manufacturers “increased design freedom and weight-saving potential, while still being able to create components that guarantee stiffness and fatigue resistance in the chassis system”.
XPF800, which offers a tensile strength of 800MPa, is the first grade of the product family to be commercially available; XPF650 and XPF1000 grades are in development. With the launch of XPF800, Tata Steel says it is ‘the first to market’ in Europe with a hot-rolled product offering high strength combined with “exceptional formability characteristics”.
A hot-dip galvanised range is also in development; this will allow thinner gauges to be used effectively, without running the risk of corrosion (a concern with thinner steel).
Tata Steel says the superior formability of XPF800 allows the light-weighting of complex vehicle components, while achieving the same fatigue performance as standard equivalent complex phase steels and high-strength low-alloy steels.
From a vehicle weight perspective, the XPF range, with its “unique nano-precipitation-strengthened single-phase ferritic microstructure and its superior product characteristics” allows manufacturers to create parts that can be more than 15% lighter than those produced with equivalent advanced steel grades — even HR CP800.
Furthermore, the improved ‘stretch flange-ability’ of XPF800 (it has an average ‘hole expansion capacity’ of 90%) allows geometric changes to a part’s design that increase stiffness while delivering mass reduction. When compared to HR CP800, the new hot-rolled XPF800 steel combines this higher stretch flange-ability with higher tensile elongation.
These characteristics ultimately lead to a reduced risk of edge shearing, allowing additional flanges and deep sections to be incorporated in chassis design to maintain — or even improve — the performance of the end product. Moreover, the formability of XPF800 not only offers light-weighting potential but also gives the opportunity to create new designs that help with parts consolidation and press-shop yield.
Freek Schut, Tata Steel’s European sales director for automotive, said: “The XPF family of steels is a major breakthrough in automotive structural-materials technology. It addresses the known challenges regarding high-strength steels for demanding chassis applications.
“Its superior product characteristics, such as stretch flange-ability and tensile elongation, give car manufacturers more design freedom and greater ability to find the right balance between cost, weight and performance benefits in the chassis area.”