The 150-kilogram weight impacts the square steel tube after a ten-meter fall from the drop tower. The test body absorbs enormous amounts of energy by means of plastic deformation. It does not splinter; instead, it folds together accurately like an accordion.
The material being tested in the applied technology lab of thyssenkrupp Steel Europe’s Technology & Innovation Business Area in Dortmund is an innovative high manganese steel. It is extremely strong and exceptionally deformable, without getting brittle or cracking. These special material properties make the steel highly suitable for a wide range of applications.
High-grade manganese steel to protect civil security vehicles
One such application is about to be introduced to the market: high manganese steel for protecting civilian security vehicles. In the coming months, thyssenkrupp Steel Europe’s subsidiary Hoesch Hohenlimburg, which produces hot-rolled specialized strip, will begin to deliver the innovative steel for the first small series of new armored cash-in-transit vehicles.
“Cash transporters and a range of other vehicles will be made using this newly developed steel in the future,” explains Dr. Andreas Tomitz, Team Leader of Product and Process Development at Hoesch Hohenlimburg.
Airbag effect: The material absorbs projectiles
Traditional steel armor plates need to be hardened in an additional step to ensure that projectiles shatter and are diverted upon impact. But the high manganese steel works on a completely different principle: Projectiles do not ricochet off the hull – they are absorbed in a fashion akin to an airbag.
“The new steel can endure much greater stress than conventional steel armor plate, even with a lower thickness, the new steel can endure much greater stress than conventional steel armor plate without extra hardening. This allows vehicle protection to be designed at a much lower thickness and thus at less cost,” says Tomitz.
The results also impressed the jury of the thyssenkrupp Innovation Contest. It awarded the expert teams from Hohenlimburg and Technology & Innovation in Duisburg and Dortmund third place for their innovation early this year. “The high manganese steel offers customers significant advantages in terms of costs and processing characteristics and opens up a whole new range of applications due to its material composition,” according to the jury.
Given the go-ahead for implementation
The hot strip experts in Hagen immediately recognized that this new material could be of great interest for the diverse products of their customers. Therefore, shortly after the first testing coils had been rolled in Hohenlimburg, they started to work on convincing their customers – mainly automotive suppliers – of the new product’s advantages. This was further facilitated by comprehensive test reports on the special mechanical properties.
The tests were successful. Just one and a half years after the first high manganese steel test coil was produced in Hagen, the customer gave the go-ahead to utilize the innovative material in actual production. “This is a new speed record,” state Tomitz and colleague Nagel with pride. And it won’t be long before the first cash transporters reinforced with high-grade manganese steel parts will appear on the streets.