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      08-17-2010, 03:57 PM   #7
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Originally Posted by Radiation Joe View Post
I posted a response earlier today, but it failed for some reason.

Short version:
8000 ton = more grain distortion = higher yield strength
Probably diminishing returns going from 4000 to 8000 tons.
Many people are willing to pay extra for the slightly higher strength.
Although I am not a forging expert I know a bit about it. I think I am going to disagree here. I'm certainly open to some proof though.

The general need for higher pressure forging machines is simply to forge larger parts from stronger materials. In the aluminum area there are many factors more important to the strength of the finished items than the forging pressure. Those include:
  • Alloy selection (new high strength aluminum alloys, e.g. K651 aluminum from Kobe Steel) can offer a whopping 40% strength advantage over more typical 6061.
  • Design: Design (as mentioned above) is way more important than forging pressure. Pushing the weight and material use very heavily will result in a weak wheel, nothing you can do about that.
  • Forging temperature: Can affect strength by a factor of 200%.
  • Heat treating: Most high strength aluminum forgings are heat treated post forging. Details of the process will greatly affect ultimate strength.
  • Forging vs. casting. Here material flow and grain alignment offers a significant strength advantage for a given design.
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