KIRCHHOFF Automotive trials Fortiform^® automotive steels for cold stamping

November 2023

KIRCHHOFF Automotive is an international automotive supplier offering body solutions that make tomorrow's mobility safe. With over 8,000 employees worldwide, the company develops and produces complex metal and hybrid structures for the body-in-white and chassis. These structures make a decisive contribution to the optimum protection of all vehicle occupants in the event of an accident. The R&D Team at KIRCHHOFF Automotive regularly researches and investigates new materials at an early stage, before the materials will be available for serial production. In a recent project, KIRCHHOFF Automotive undertook an assessment of ArcelorMittal’s Fortiform^® ultra high strength steel for cold stamping at its R&D facilities in Germany and Canada.

Fortiform^® allows OEMs to develop structural elements using cold forming methods such as stamping. As Fortiform^® steels have higher mechanical properties than conventional advanced high strength steels (AHSS), they can provide additional weight reduction while maintaining the same level of formability. KIRCHHOFF Automotive’s assessment of Fortiform^® aimed to prove that the weight reduction and formability potential of the steel could be achieved in a complex door beam part.

The carbon footprint shown in the image above demonstrates the effect weight reduction has on component emissions. The example shows emissions for two automotive steel grades produced via the standard blast furnace route. ArcelorMittal’s steel from blast furnace routes can be supplied with XCarb^® green steel certificates. These certificates allow customers to reduce their Scope 3 emissions significantly.

Complex door beam tests material capabilities

ArcelorMittal delivered samples of Fortiform^® 980, 1050, 1180, and 1270 to KIRCHHOFF Automotive for the assessment. The samples were formed at the prototype shop of KIRCHHOFF Automotive in Attendorn (Germany) using a customer-independent demonstrator tool for a door impact beam. The tool was designed to compare different new cold-formable high strength steels. The tool tests the whole product chain including forming and three-point bending.

For the forming investigation, a grid was etched into the steel samples. This allowed the formability of the part to be accurately measured and compared to the numerical simulation which used forming data cards provided by ArcelorMittal.

The following table shows the comparison between the part (with grid) formed from Fortiform^® 980 (top row) and the numerical simulation (bottom) for both major and minor strains. The simulation accurately predicts the forming behaviour.

Results show Fortiform^® meets expectations

Quasistatic three-point bending tests were also performed at KIRCHHOFF Automotive's Testing Center in Attendorn to compare the force deflection behaviour. The formed parts were compared to simulations with crash data cards provided by ArcelorMittal.

The results showed that the Fortiform^® parts performed as expected.

There is a good correlation between the force displacement curves when comparing the simulation to the physical bending test:

The collaboration between KIRCHHOFF Automotive and ArcelorMittal showcases the pioneering spirit driving innovation within the automotive and steel industries. KIRCHHOFF Automotive's rigorous assessment of Fortiform^® ultra high strength steel exemplifies their dedication to excellence and their commitment to develop safer and more sustainable mobility. This forward-looking initiative demonstrates the viability of cold stamping methods for developing structural elements and underscores the significant potential for emission reduction. By utilizing the full potential and capabilities of Fortiform^® and other advanced steels, KIRCHHOFF Automotive and ArcelorMittal continue to pave the way for a future where safety, performance, and environmental consciousness align harmoniously.

About KIRCHHOFF Automotive

KIRCHHOFF Automotive offers body solutions that make tomorrow's mobility safe. Innovative and economical lightweight products ensure that people are optimally protected in the event of an accident. As a supplier to the automotive industry, KIRCHHOFF Automotive develops and produces complex metal and hybrid structures for body-in-white and chassis that are lightweight, economical and crash-proof. Because the vehicles of the future - from electric to autonomous - also need bodies that ensure the greatest possible safety for all those involved in an accident in the event of an emergency.
KIRCHHOFF Automotive has a presence across Europe, Asia and North America; with more than 8,000 employees and 27 production plants in 11 countries, KIRCHHOFF Automotive represents the largest division in the group. The family-owned company, which has existed since 1785, is part of today's KIRCHHOFF Group, which is made up of the Automotive, Ecotec, Mobility and WITTE Tools divisions. 

About ArcelorMittal

ArcelorMittal is the world's leading steel and mining company, with a presence in 60 countries and primary steelmaking facilities in 16 countries. In 2021, ArcelorMittal had revenues of $76.6 billion and crude steel production of 69.1 million metric tonnes, while iron ore production reached 50.9 million metric tonnes.
Our purpose is to produce ever smarter steels that have a positive benefit for people and planet. Steels made using innovative processes which use less energy, emit significantly less carbon and reduce costs. Steels that are cleaner, stronger and reusable. Steels for electric vehicles and renewable energy infrastructure that will support societies as they transform through this century. With steel at our core, our inventive people and an entrepreneurial culture at heart, we will support the world in making that change. This is what we believe it takes to be the steel company of the future.
ArcelorMittal is listed on the stock exchanges of New York (MT), Amsterdam (MT), Paris (MT), Luxembourg (MT) and on the Spanish stock exchanges of Barcelona, Bilbao, Madrid and Valencia (MTS).