New solutions for the automotive industry

Efficient lightweight construction

High-tensile steel is the most important material for economically efficient lightweight construction – and it is critical for the automotive industry. This is because minimising the weight of several different products and parts reduces the overall weight, thereby making a significant contribution to cutting CO2 emissions.

Further reducing the weight of vehicles is one of the crucial challenges facing the mobility sector in future. In its quest to further investigate the potential of solid lightweight construction for car manufacturing, GMH Gruppe has been involved in the cross-industry Lightweight Forging Initiative since 2013. This cooperation has already developed several new ideas for reducing the weight of cars and commercial vehicles. These ideas demonstrate that lightweight solutions using high-performance steel are both competitive and cost-effective. 

Scrutinising the entire process chain 

The Lightweight Forging Initiative has brought together a total of 15 solid forming companies and nine steel manufacturers under the umbrella of the 'German Industrial Association for Forging' and the 'Steel Institute VDEh'. The foundation of the Initiative represented the first time that the manufacturers and component suppliers for the entire long product process chain had worked together. They collaborate to develop solutions that are viable in terms of their lightweight construction, cost and implementation potential.

Based on workshops and studies

In the workshops, experts discuss how the weight of individual components can be reduced – from crankshafts and gear shafts to gear wheels and bolts. Two industrial studies were launched specifically to analyse the lightweight construction potential for medium-class cars and light commercial vehicles weighing up to 3.5 tonnes – focusing in particular on the drive train and chassis. 

In Phase 1, a lightweight construction potential of 42 kg was calculated for the cars. In Phase 2, the figure was almost 100 kg – this time in the field of light commercial vehicles. The companies financed the study, entitled ‘Lightweight construction potential in solid-formed components for cars’, without any public funding. The study was conducted in partnership with the Aachen research association for automotive engineering (fka). It investigated which solid-formed steel components are used in cars, and how they could be optimised for a more lightweight design.

535 new lightweight construction ideas 

The combining of expertise in areas from steel manufacturing and forming through to the end product itself has led to - and is still leading to-  the birth of many solutions that would almost certainly have been impossible without this collaboration. In total, 535 lightweight construction ideas have been defined for 2,536 components. The lightweight construction potential proposals for steel alone highlight the enormous lightweight construction potential of 65 kg. A further 34 kg can be saved by using non-ferrous materials. As such, the lightweight construction ideas developed through the collaboration result in an impressive 11.7 per cent weight reduction in the drive train and chassis. 

It goes without saying that costs also play an important part. The engineers calculated a weight saving of 2.45 kg for a manual gearbox, with additional costs of less than €1 per kilogram saved. 

Lightweight construction is competitive

The Lightweight Forging Initiative shows that the use of modern steel materials in forging technology plays a significant role in ensuring that the automotive industry’s lightweight construction needs are met. Moreover, the two studies also prove that new ideas can generate tangible competitive advantages compared to other production processes and materials. Unlike technological advances such as honeycombs, foam and 3D printing, lightweight construction will only be rolled out once it is cost-effective and can be used in large series. 

The great potential of lightweight components 

Until now, lightweight construction has always meant savings in the bodywork and plate-metal-based solutions. But there is just as much potential in the drive train (injection system, engine, gearbox, transfer gearbox, drive shafts) and chassis. There has been little focus thus far on the potential of these areas – and usually only as part of a system-level solution approach, such as attempts at engine downsizing. Little attention has been paid to lightweight construction potential in terms of materials and solid forming. 

Yet solid-formed steel components can save a considerable amount of weight in vehicle construction. Our development results show that using the latest steel material and solid-forming technology can directly reduce the weight of a medium-class vehicle by four kilograms. As such, lightweight construction has far-reaching effects and helps to reduce the energy consumption and overall CO2 emissions of vehicles. 

Balancing the weight

The total weight of the reference vehicle used in the study (125 kW/170 hp, 2.0 l Turbo DI, diesel, dual-clutch gearbox, all-wheel drive) was 1,740 kg. 838 kg of this weight was analysed – around 3,500 parts from the drive train, chassis and other selected components. A total implementable lightweight construction potential of 42 kg was identified for the areas in question.

From idea to implementation

The ideas developed in the workshops were not intended as finished solutions. Some are stimuli that highlight the opportunities offered by lightweight construction in terms of design, materials and production, leading to both cost and weight savings (quick wins). Other ideas revealed potential savings that would only be possible if more money or development time were invested in the project. And what else does the future hold? At GMH Gruppe, we continue to partner with and contribute to the Initiative because this collaborative development work is always yielding new ideas and inspiration for steel manufacturing and for partnerships with our customers.

Summary

High-tensile steel is the most important material for economically efficient lightweight construction – and it is critical for the automotive industry. This is because minimising the weight of several different products and parts reduces the overall weight, thereby making a significant contribution to cutting CO2 emissions.

Contact person

GMH Gruppe, Georgsmarienhuette, Thomas Wurm

Dr. Thomas Wurm

Head of Technical Customer Support and Application Development Georgsmarienhütte GmbH