From Mild To High-Strength: Cost/Benefit of Automotive Steel Today

Ron Krupitzer paints AISI as the central hub of cooperation between steel companies and automotive OEMs.

MetalMiner recently had the chance to sit down with Ron Krupitzer, vice president, automotive market for the Steel Market Development Institute.

Having covered the aluminum industry’s involvement in lightweighting, we wanted to get the steel perspective on the issue.

Ron began his career as a metallurgist/researcher at Republic Steel in Cleveland, then moved to Chrysler and put his research to use for 8 years in R&D and engineering. He finally moved to stamping, actually making the products that he had been researching before retiring from Chrysler — which offers him a singular perspective on how the steel and automotive sectors come together.

MetalMiner: Richard Schultz from Ducker Worldwide, presenting at Aluminum Week in Chicago, said something to the effect that “advanced high-strength steel (AHSS) costs, let’s say, $.50 per pound, while aluminum is around $2 per pound, and that even at $2 per pound, aluminum is looking increasingly more attractive to auto OEMs.” What is your response to that?

Ron Krupitzer: In many cases, the opportunity for aluminum depends on exactly how much mass it can save compared current steel prices - MetalMiner IndXto steel. Most comparisons are against mild steel, steel typically used 10 to 15 years ago to build vehicles. The properties of that material are great formability and corrosion resistance. But it doesn’t offer the opportunity for weight reduction. Today, we’ve created an entire portfolio of steels that are two, three, even five times as strong as those steels. Our most recent study is FutureSteelVehicle, launched in 2011, which shows that it’s certainly possible to save just as much weight [with AHSS] as it is with aluminum.

For example, the passenger compartment now has to be extremely strong; it has to absorb energy and withstand impact in frontal crash. And the selection of crash tests now are so demanding of the vehicle that engineers have redesigned the entire structure of the vehicle to pass these tests. If you look at today’s designs, all are taking advantage of the new steel products. What we call ‘ultra high-strength,’ or GigaPascal[-strength] steels, are especially helpful for side impact or roof-crush — these are the steels over 1,000 Megapascals — that means that they’re five times as strong as conventional mild steels were 10 to 15 years ago. The cost-and-mass balance is actually in favor of steel, and no one would consider rebuilding the vehicles using other materials — not that it couldn’t be done, but the cost would be so incredible that there’d be no point. The mass saved is pretty remarkable.

Where there are extreme demands for load cases, like in bumpers where they’re now being designed as a component of crash management, steel has a tremendous advantage, mainly due to its wide range of available strengths. In body panels or in hoods, the load cases are not quite so severe, so in those cases, while steel offers the most affordable solution, it may not be the exact aluminum prices - MetalMiner IndXlightest solution — [ultimately] it’s going to be up to each car company to decide where it wants to invest its money, for how much mass it wants to save…Each car company may also need to consider how much it can afford to spend with some low-density materials.

The interview will continue in Part Two, when we get into OEM margins and lifecycle costs.

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