New TriBond composite: high strength and good formability for weight-optimized parts

ThyssenKrupp Steel Europe is opening up new potential for auto manufacturers: Hot-formed parts made from the new three-layer steel composite TriBond offer very high strength of 1,400 megapascals but can absorb more crash energy than the reference made from MBW 1500. They are also up to ten percent lighter than current hot-formed solutions. The intelligent steel composite will achieve production status in mid-2015. Prior to that, the new TriBond product family will be presented at roadshows. Customers can find out about these innovations for the auto industry at this year’s EuroBLECH show from October 21 to 25 in Hanover, hall 17, booth E 33.

Flexible, three-layer structure

ThyssenKrupp Steel Europe is exploring innovative approaches to making the cars of the future even lighter. The hybrid material TriBond is a product family that opens up new perspectives. Steel sandwich structures make it possible to combine different and in part conflicting material properties in one product. Completely new properties which cannot be produced using two single materials can be created through a tailored combination of functional layers. For example TriBond – for hot forming – comprises three layers: a high-strength steel core between outer layers of ductile, readily formable steel. The structure is flexible; in principle, different steel grades can be combined in varying thickness ratios. That opens up a broad product range for application-oriented and tailored materials.

High strength and very good energy absorption

ThyssenKrupp Steel Europe is currently developing two initial variants – TriBond 1200 and 1400 – which are already undergoing testing at customers. The auto industry generally uses steels in this strength class for crash-relevant structural parts such as A and B-pillars. The Duisburg-based company has tested the new material extensively using a specially developed modular simulation method and in real crash tests. The results are conclusive: The B-pillars in the TriBond 1400 test series displayed no cracking whatsoever in the deformation zone and impressive energy absorption capacity. In other words: The very high strength of TriBond means that thin-walled and thus lightweight components still provide very good occupant protection in the event of a crash while also absorbing impact energy.

New possibilities for hot forming

TriBond also opens up whole new possibilities for hot forming. To date, hot-formed parts have mainly been used for high-strength structural elements where energy absorption plays a secondary role. For energy absorption they need to be combined with a softer material, e.g. by means of tailored blanks in which different materials are welded together, or by tailored tempering, which uses temperature control during hot forming to create a strength gradient in the part. The new composite combines both properties – high strength and high energy absorption – in the material itself. No additional measures are needed. TriBond is also suitable for areas of the body subject to axial crash loads such as longitudinal members and crash boxes.

Processing on standard equipment

TriBond also offers further benefits: Parts made from the new hybrid material are up to ten percent lighter than the current solution of MBW 1500 produced by tailored tempering, and costs are attractive. It is produced in similar fashion to conventional cold-rolled strip, but with an additional package-building operation in which the steel layers are laid on top of each other and joined. Both manufacturing and fabrication at automotive customers can be carried out on standard production equipment.

Visit us at EuroBLECH 2014 in Hanover from October 21 to 25, hall 17, booth E 33.