Automakers are faced with a double-fold challenge: while called on to reduce vehicle weight, they are asked to improve safety and maintain affordability, requirements that are in direct opposition to each other.
To address cost, material selection becomes the crucial factor. Competitive materials, such as aluminium, are at a significant cost disadvantage over steel for all aspects of the car body structure manufacturing process.
Moreover, the high material costs of aluminium, driven by the energy required to produce it, represent only 15% of the cost premium, the remainder being a result of the high manufacturing and assembly costs associated with this low-density material.
Steel achievements
Steel is the only automotive material that bridges the performance—cost gap.
Optimized steel body structures using AHSS can be constructed at little or no additional total system cost relative to a conventional steel body structure.
This has been clearly demonstrated in the ULSAB family of research studies. Both the 25% lighter ULSAB high-strength steel and the 25% lighter ULSAB-AVC AHSS design, while meeting the aggressive 2004 crash requirements, represent no cost penalty for manufacturers.
Automotive manufacturers have been able to duplicate these results in their own designs and have reached the same conclusions on the affordable weight-reduction enabled by optimized advanced steel designs.
The Case
A presentation at the International Aluminium Conference by Richard Schultz, aluminium consultant and former President of Alcoa Automotive Structures, concludes that an aluminium car body structure costs automakers between US$1,400 to US$4,600 per vehicle more on average depending on production volume, or a 65% premium over a steel car body frame.
An effective and successful vehicle mass reduction programme is one that provides affordable solutions that can be sustained over time.
Looking to the future
Through the Future Steel Vehicle (FSV) programme, WorldAutoSteel commits to Advanced High-Strength Steels (AHSS) that ensure the continuing cost advantage of steel.
This lightweight—cost connection will be enhanced over time with the delivery of body concepts that address alternative powertrains, such as advanced hybrid, electric, and fuel cell systems.
References
Massachusetts Institute of Technology (MIT), Study on Process Cost Modelling, 2007
Presentation by Richard Schultz, aluminium consultant and former President of Alcoa Automotive Structures, at the International Aluminium Conference
