Steel Your World. What does that mean? For WorldAutoSteel, the automotive group of the World Steel Association, it means increasing applications of a growing new family – Advanced High-Strength Steels (AHSS) – in vehicle structures that deliver lightweighting, a reduced environmental footprint and improved safety. We’re very confident these steels can do the job, but what do our customers really think?
We decided to go out and ask them, and we’ve captured their unscripted, spontaneous responses in a video series called SteelYourWorld. The first video, Steel Your Weight, launched on 13 September features automakers, academics and WorldAutoSteel member engineers.
“Advanced High-Strength Steels will always be a first line of defence in the automotive industry in trying to reduce mass.” — Curt Horvath, General Motors
AHSS is finding its way into nearly every new vehicle on the market today. Why is this so when steel is perceived as old and unsophisticated by many? What many do not know, is that steels today are very different than they were even a decade ago, newer than many of their “new” lightweighting competitors.
As one of our members, Kinshuk Roy of JSW Steel India said, “Steel cannot be matched by any other material for lightweighting because we can develop any property needed simply by designing the steel composition to suit [the need].” This is what sets steel apart from all other materials.
Steels are produced by alloying a high concentration of iron (Fe) with very small concentrations of carbon (C), along with a “recipe” of other elements to develop distinct characteristics that broaden their application appeal. From its vantage point on the Periodic Table of Elements, the Fe element commands many partnerships. Its balanced nature—26 electrons, 8 in the valence shell—enables iron to bond easily with a wide range of other elements. How an element bonds with itself and other elements determines, largely, its usefulness as a structural material. In comparison, aluminium only has 3 electrons in the valence shell and magnesium, 2.
By carefully controlling the recipe and the amount of heat and deformation during material production, different characteristics are achieved that contribute to steel’s structural use. The steel changes, called phase transformations, during production result in incredible strength levels, while also allowing it to be formed into complex component shapes necessary for today’s vehicles. Other phase transformations are induced during the shaping of the vehicle components. These transformations result in components that can either be strong and rigid to deflect energy in side-impact crash situations, or absorb and dissipate crash energy, such as in a front crash.
Because iron’s eight valance shell is friendly with oxygen’s six, it requires four times less energy to convert raw iron oxide into steel, producing seven to 20 times less greenhouse gas emissions than any other automotive material.
Renowned Professor Julian Allwood of Cambridge University claims that steel “by far exhibits the most efficient conversion process on the planet.” The low energy consumption leads to low production costs.
Ultra-low production emissions allow AHSS to be unique as the only material that lowers emissions throughout the vehicle's entire life cycle, from manufacture to scrap yard. This attribute becomes increasingly important with time, as our planet’s climate change countermeasures become more dramatic.
And in all of this, strength levels have increased tenfold over steels of a decade or two ago, and that’s where real value to lightweighting comes in—if you can make the steel thinner and maintain or improve the strength, you use less steel and weight is reduced.
Lightweighting can be done affordably with steel, which is no longer ignored by even premium brand manufacturers. We recently heard this from Audi’s head for its Lightweight Construction Center, Dr. Bernd Mlekusch, speaking at the North American Green Car Congress, “There will be no cars made of aluminum alone in the future. Press hardened steels [a member of the AHSS family] will play a special role in this development.”
Automakers will continue to steel their world as the steel industry continues to offer new, advanced materials. Stay tuned to worldautosteel.org as we roll out the rest of the videos in our series. Three other videos will be released over the next year: Steel Your Future, Steel Your Strength and Steel Your Environment, each a compilation of insights from our interviews.