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Mysterious dense alloy

  1. Sep 4, 2013 #1
    I would like to identify a mysteriously dense metal I have in my possession. I bought a big box of engineering bits, along with a lathe, and found what I thought were High Speed Steel tool blanks which felt very heavy. I worked out the relative density and it is an amazing 16.97. The material is non-magnetic and grinds like silver steel (unhardened tool steel); I haven't tried machining with it. The closest element is Tantalum at 16.7 but it's not that because tantalum is soft.
    The only marking on each piece is EDF 32851 and each piece is about 9 x 9 x 155mm.
    Any ideas?
  2. jcsd
  3. Sep 4, 2013 #2


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    Could it be tungsten carbide (density 15.6)? It is often used for drill bits.
  4. Sep 4, 2013 #3
    That was quick- and I never thought of TC. It's not though because it can be filed, although it is quite hard. It appears to be cast then ground to clean up, but not precision ground; this might help as a clue.
  5. Sep 4, 2013 #4
    It basically has to be a tungsten alloy -- any other metal that dense is either too expensive and/or poisonous. So unless someone made a set of platinum drill bits, in which case you are pretty lucky, it's probably one of http://www.cmwinc.com/tungsten-alloys.php [Broken], or something like them.
    Last edited by a moderator: May 6, 2017
  6. Sep 5, 2013 #5
    Fantastic! I spent hours searching without finding that. This seems very likely. In the link you provided, their rd17 material is made for boring bars where it's stiffness and high mass reduce chatter -vibration which leaves poor surface finish- when machining deep holes on a lathe. It would explain why this material turned up in a box of assorted engineering bits.
    One day I'll get around to trying it out; when I do I'll report back.
  7. Sep 18, 2013 #6


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    Can't be depleted uranium can it? ;)
  8. Sep 18, 2013 #7
    I'm not encased in a green glow so I'll stick with the tungsten alloy story.
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