There’s a lot of talk about fiber-reinforced and composite materials in the public and trade media, while the potential offered by our old friend steel has been somewhat lost from sight. But in terms of its manufacturing process, steel is superior to other materials such as aluminum and carbon.
He has data from the VDEh Steel Institute to back him up. "Primary production of one ton of steel corresponds to about two tons of CO₂, compared to ten tons for aluminum and more than 20 tons for CFRP," comments institute spokesperson Christoph Keul. "When you include recycling in the footprint, production of one ton of steel over several recycling intervals releases even less than one ton of carbon dioxide."
"If you look at the entire life cycle from production through use to recycling, high-strength steel produces lower CO₂ emissions," says Frank Heidelberger, Marketing Director of steelmaker Salzgitter Flachstahl.
Enormous potential for lightweight construction
The possibilities for reducing weight and raw material consumption for forged components have been explored by the “Large-scale Lightweight Construction Initiative”, for example. This association of bulk forming and steel production firms published a passenger car potential study, which was followed by a commercial vehicle study. From the end of 2014 until October 2015, the 28 participating companies and institutes analyzed the reference vehicle: a van with a total weight of 3.5 t including cargo, with a 120 kW drive train, 2.1 liter engine and turbo diesel direct fuel injection, as well as a manual transmission and rear wheel drive.
The conclusion: of the 2,394 kg of vehicle weight considered, 845 kg came from bulk formed components, which represented the optimization potential of the study. The resulting investigation identified a savings potential of 99 kg. Because mainly steel and aluminum sheet metal is used in the body, this savings could be found primarily in the drive train and chassis: wheel hubs and injection system, crankshaft, gears and other components.
“That’s 99 kg more cargo for the same total weight, or – with the same cargo – a reduction in weight and fuel consumption,” is how Hans-Willi Raedt, Vice President of automotive supplier Hirschvogel and spokesperson for the lightweight construction initiative, sums up this potential. He is not surprised by the results: “Unlike many body components, bulk formed components have received very little attention for many decades.”
Redesign and development is not that simple in the metal production and processing sector, with its high division of labor. “Redesigning a component like a universal joint knuckle requires getting everyone along the value chain on board: steel producers, bulk formers, machinists, system manufacturers and original equipment manufacturers, as well as carmakers,” explains Raedt.
The initiative made 535 recommendations in all, most of which involve lightweight construction design, followed by manufacturing solutions and lightweight construction materials. For Raedt this is no accident: “Bulk forming specialists are masters of design methods.”