这车跟MDX的ultra high strength steel frame 比那个更结实呢？
The Safety of Steel
When it comes to producing cost-effective structures that can resist
intrusion, steel provides the competitive edge.
Article From: Automotive Design & Production Gary S. Vasilash , Editor-in-
Chief
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Posted on: 5/30/2014
The 2014 Acura MDX has something that no other vehicle did when it was
launched. It has the world’s first ultra- high strength steel, one-piece
stiffener ring. It’s the A-pillar and the B-pillar. It’s the roof rail and
the lower frame member. According to Dr. Blake Zuidema, Director of
Automotive Product Applications, ArcelorMittal Global R&D (corporate.
arcelormittal.com), that stiffener ring is not only the result of
advancements in metallurgy, but involved hot-stamping and laser welding. The
purpose of all of that technology is to make the MDX safer. The ring is
designed to manage energy not only in the case of side impacts, but also for
frontal offset collisions and in rollover situations.
When it comes to safety, stronger is better, and Zuidema points out that
when it comes to producing cost-effective structures that can resist
intrusion—the sort of thing that you’re looking to do when engineering a
passenger compartment—then steel provides the competitive edge.
He cites, for example, the company’s Usibor steel, a press-hardened boron
steel with an aluminum-silicon coating that provides a strength of 1,500 MPa
after hot-stamping. And suggests that this is much stronger than any alumi
- num alloys on the market right now. What’s more, he notes, that this
strength provided by the steel doesn’t come at the cost of a mass penalty
But what about composite materials? Strong, light, safe, right?
Yes. But: Zuidema points out, making a door aperture like the one created
for the MDX would be far-more labor intensive, which leads to “substantial
cost to manufacture.” Which leads to substantial cost to put in a vehicle.
While aluminum and composite materials seem to be bright, shiny and new, and
consequently catching a whole lot of attention, Zuidema says that most of
the steel grades that are going into cars today weren’t available 10 years
ago, so when it comes to contemporary relevancy and capability, it’s not
like this is some classic HSLA material. And he says that work is ongoing to
produce steels that are stronger with even better formability, which are a
couple years away from being commercially available.
Speaking of formability, if some of the materials being formed are “three
to four times the strength of the highest- strength aluminum alloys that
are available now,” isn’t there a manufacturing challenge presented by
these new steels? Zuidema says that that’s not the case, that while there
are some new guidelines for stamping, “Steel uses the same press shop and
the same body assembly techniques, the same spot welding, MIG welding, and
the same basic adhesives.” Whatever changes there are in the production
operations, he says, “The cost of converting is far, far lower than it
would be for converting to aluminum or carbon fiber.”
The big challenge being faced by OEMs is the 54.5 CAFE target for 2025.
Zuidema says that that number can be achieved with the grades of steel that
are available now. What’s more, compared with alternatives, it can be done
so economically compared with the alternatives. “They might be a little bit
lighter,” he admits, “but steel gets you there at a lower cost.”
