Hot Stamping

Hot Stamping is the process by which steel blanks are heated, pressed into shape, and rapidly cooled to produce a more efficiently formed, stronger part.  There are two main methods of hot stamping (direct and indirect), the processes of which are outlined in Figure 2.  By heating up the blanks, they are more easily molded to their desired shape than other methods like cold stamping.  The end product of hot stScreen Shot 2015-12-04 at 10.27.15 PMamping is a thinner, lighter piece of steel that can replace what would be a heavier, thicker part, while still increasing the relative strength of the frame.  This allows manufacturers, namely in the automotive business, to either lower the
overall weight of the car, or move the weight elsewhere for stabilization.  With a lighter frame, cars are able to get better gas mileage, which has evidently been a big selling point in recent years.

Screen Shot 2015-12-04 at 10.25.51 PMHot stamped parts also come with the benefit of being safer.  The process minimizes springback and generally gives the steel better crash properties.   The highlighted parts in Figure 1 are most commonly hot stamped, and as shown, it is now strategically used for most of the frame.  As a whole, hot stamping has allowed car manufacturers to be more creative with weight distribution and the overall design of the car frame.

 

Sources:

http://www.elsevierscitech.com/lmfile/otherformat/karbasian_tekkaya.pdf

 

10 thoughts on “Hot Stamping

  1. As someone who worked in a body shop back in high school, writing up repair estimates for insurance companies and helping to manage a body shop, I wonder how these hot stamped parts will affect the repair-ability of new cars. When repairing cars, it is often crucial to be able to pull and hammer dents and creases to return metal to its original shape. I wonder how these new hot stamped metals react to being repaired, specifically, if they maintain their safety related “crumple properties.”

    • Something that would damage these steels likely leaves the car a heap of scrap. Maybe a door could be caved in, but then you just replace the whole thing. If it’s the frame, it can’t be repaired. But there’s more chance the occupants survived, and with less damage to themselves.

    • As prof. said, this process is really only being used for the frame, not for the exterior paneling and such. The “front bumper” label on the second image is actually referring to the frame underneath the bumper, not the actual bumper itself. The process is really about the structure being lighter, as well as being stronger in the case of a serious accident.

  2. What are the costs involved with switching to a hot stamp system? I imagine the capital costs are tremendous, so I’m curious whether the smaller firms could afford to change their system, or would be stuck with less efficient methods.

    • It’s technically challenging but these sorts of car frame parts are made by only a handful of outside suppliers globally, all typically large firms with footprints in various component segments. So funding isn’t an issue, but whether to fund (will it be profitable?) remains a consideration.

      Many car assemblers do their own stampings, though there’s lots of variation. Light trucks are more likely to have outside firms doing their frames, but those don’t (yet?) use hot stampings. Recent changes in crash tests may change that…

  3. Where do you see the future of hot stamping going? Obviously there are significant advantages to this technique, but is there anything that you read that indicates future innovations? The automobile industry is the first that comes to mind, but it seems that hot stamping could open the door to many more avenues of value-added steel production.

    • Hot stamping in some way links back to the steel industry’s response to increased use of aluminum in cars. Ford recently decided to switch a large portion of the F 150 to aluminum rather than steel, delivering a blow to ArcelorMittal. According to the article I read, total North American use of light vehicle aluminum will increase by 28% in 2015 (from 2012). Hot stamping has been part of the steel industry’s approach to produce lighter steel. ArcelorMittal seeks to reduce cost as well as weight. The next steep in innovation may be 3D printing of ultra-thin panels. Door panels become wavy at a certain point of thinness. 3D printing allows steel makers to offset this with the inclusion of stiffeners or stiffening materials overlaying the steel.

      Source: http://www.metal.com/newscontent/83008_steel-fights-back-looks-to-hot-pressing-3d-printing-to-win-back-automotive-market

  4. Wyatt,

    You are right about the automobile industry adopting this technique. Hot-formed steel is being used by many car manufacturers on entry-level vehicles as a way of saving weight and strengthening critical components of the vehicle, like Brennan mentioned in his post. However, strengthening or reshaping even minor deformations (say a car accident) are not possible when using the hot-formed steel method. A damaged component must be completely cut out or partially replaced. So, while there are many benefits to this new method, there are also higher costs of repair.

    • Due to the nature of these repairs, I wonder how it will effect the output of the scrap metal. This could be another cause for increases in the cost of these repairs because previously where they could possibly see this scrap to scrap metal companies for a decent price, the recent drop in prices cause smaller margins. Thus when companies charge more for the specialized goods and the buyers of scrap curt their buying prices we can only expect an increase in price of these hot stamped repairs.

  5. It will be interesting to watch how hot stamping will adapt to the natural inflation of car prices, given hot stamping will be mostly used on cheaper cars. As prices get more expensive, customers may have issues with the hot stamping when it comes to repairing the car.

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