Innovative lightweighting project could reduce vehicle weight by 20%
10.27.2020
ArcelorMittal and Diversitak teamed with experts from Oak Ridge and Idaho National Laboratories on an inventive and aggressive automotive lightweighting project funded by the U.S. Department of Energy’s Lightweight Materials Consortium (LightMAT). The project leveraged our advanced high strength steels at ultra-thin levels with a new technology to meet automakers’ performance requirements – a carbon-fiber spray applied to dent-prone spots.
Lightweight design has become the most prominent engineering requirement in the automotive industry. Regardless of how a vehicle is powered, whether it be an internal combustion engine, electric battery or hydrogen fuel cell, optimizing weight is critical for increasing mileage while maintaining safety and comfort.
There has been an intense drive to accelerate advanced materials development with mixed materials, but design constraints, cost and performance requirements have limited their usage.
A two-year, $300,000 grant was given to the partners to continue testing started a few years ago by ArcelorMittal, Ford and Diversitak. In the original independent study, the steel roof in a test vehicle was reduced in thickness from 0.75 to 0.65 mm. Then Diversitak’s carbon fiber spray was applied to ArcelorMittal’s bake-hardenable 210 grade steel. The results were excellent, with the carbon-fiber reinforced steel meeting all requirements for stiffness and dent resistance.
Hot stamped door outer panel (interior and exterior views)
“Government funding for this steel-based project underscores the importance and viability of advanced high-strength steel as an automotive material,” said Michael Lizak, global technology coordinator for automotive at ArcelorMittal R&D. “This was one of the most favorable LightMAT studies with two national labs working on it.”
Oak Ridge National Lab’s carbon materials expertise and Idaho National Lab’s chemistry, metallography and high-resolution imaging capability helped the partners develop and ensure the integrity of the interface between the coating and steel.
The back surface of a door reinforced with carbon fiber spray in areas most susceptible to denting damage
The team developed the carbon fiber reinforced epoxy (CFRE) technology with ultra-thin advanced high strength steel body panels, down from 0.75 to 0.55 millimeters. This new manufacturing process can reduce body mass by 20%! The team also formed a better understanding of how to apply the coating, how it performs in service and the long-term durability of materials manufactured using this technology.
“Multiple automakers have expressed interest in this project – targeting doors, then fenders, body side outers and hoods,” explained Lizak. “One OEM’s goal is to reduce all exposed panels to .6 millimeters and this solution will get them there.”
Future work involves collaborating with target OEM customers to prove out and validate select panels. The robotic spray application method also needs to be developed, but the product is compatible in automotive assembly processes in several ways.
This exciting new product will be application ready in the first half of 2021.
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