New AHSS Weldable Grade Aids in Auto Weight SavingsMarch 4, 2020
ArcelorMittal USA Inc. has added to its family of advanced high-strength steels (AHSS) for automotive with the development of Fortiform 980 Extragal, joining Fortiform 1050 (available in Europe only) and Fortiform 1180. This third-generation double-sided, pure-zinc-galvanized steel eliminates concerns with the second-gen. grades, where body engineers had some limitations in using them for parts involved in energy absorption or those with complex shapes, according to ArcelorMittal officials.
Fortiform 980 Extragal, with a tensile-strength of 980-1130 MPa, reportedly is compatible with current automotive-industry welding systems, and was engineered to mitigate typical AHSS challenges such as liquid-metal embrittlement and optimum weld strength. ArcelorMittal has studied interaction of the steel with resistance spot welding, laser welding, gas metal arc brazing and gas metal arc welding with no signs of surface cracks in critical zones.
“The new Fortiform 980 Extragal (-GI) range of AHSS for cold stamping combines superior formability and ductility at higher strengths that exceed the capabilities of the second-generation AHSS, thus opening up significant new opportunities for AHSS in body engineering,” says Hassan Ghassemi-Armaki, lead research engineer for ArcelorMIttals’ Global Research and Development department in East Chicago, IL. “This is a crucial advantage as carmakers come under pressure to further lighten vehicles as a part of their strategy to improve fuel economy.”
And, explains Qaiser Khan, senior engineer in the company’s East Chicago Global Research and Development department: “Because of its superior properties, Fortiform 980 Extragal could help achieve weight savings of as much as 20 percent as compared to conventional AHSS while meeting increasingly stringent crash and safety requirements.
This grade, according to Khan, is suitable for use in many impact-affected structural parts of the vehicle, including front and rear rails.
See also: ArcelorMittal USA Inc.
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