1. Click here to enter the drawing for your chance to win an Ontario Knives Spec Plus SP8 Machete Survival Knife & Ka-Bar Dozier Folding Hunter, , Bladeforums.com swag or memberships!

    Be sure to read the rules before entering, then help us decide next week's giveaway by hitting the poll in that thread! Entries close at midnight, Saturday Sept 7!

    Once the entries close, we'll live stream the drawing on Sunday, Sept 8 at 5PM Eastern. Tune in to our YouTube channel TheRealBladeForums for a chance to win bonus prizes!

    Questions? Comments? Post in the discussion thread here

Call for Charpy toughness samples

Discussion in 'Shop Talk - BladeSmith Questions and Answers' started by Larrin, Jan 26, 2018.

  1. rodriguez7

    rodriguez7 Gila wilderness knife works Knifemaker / Craftsman / Service Provider

    Feb 1, 2009
    Very curious about the 4% nickel and a8! Should be some tough stuff. If the a8 is heat treated similar to infi, it’ll be very interesting! Can’t wait to see. Larrin has his work cut out for him!!
     
    hugofeynman likes this.
  2. Mecha

    Mecha Madscienceforge.com Knifemaker / Craftsman / Service Provider

    Dec 27, 2013
    I'd love to have a forged piece of the titanium alloy I use for swords tested. Someone else would have to be able to surface grind the sample to final tolerances, though. What a tiny test sample! I might torch it in the HT. :D Is it not a V-notch test?
     
    hugofeynman likes this.
  3. Larrin

    Larrin Gold Member Gold Member

    Jan 17, 2004
    We tested the three 15N20 samples and got somewhat disappointing results. We got values of 8.9, 9.0, and 23.8 ft-lbs. So we got two low values and one much higher value, meaning it is difficult to conclude much from the tests. None of those values are anywhere close to the toughness measured for AEB-L. The results might be inconsistent due to their prior use as saw blades, but we're not really sure.

    The heat treatment was: subcritical anneal at 1175°F, austenitize at 1475°F, quench in Parks #50, liquid nitrogen for 20 minutes, temper 2x at 375°F for final hardness of 60 Rc.
     
    Last edited: Feb 5, 2018
  4. Larrin

    Larrin Gold Member Gold Member

    Jan 17, 2004
    For knife steels, v-notch testing results in extremely low values.
     
  5. kuraki

    kuraki Fimbulvetr Knifeworks

    Jun 17, 2016
    I'll include a couple fresh stock 15N20 samples. Still waiting on coils for the furnace.
     
  6. rodriguez7

    rodriguez7 Gila wilderness knife works Knifemaker / Craftsman / Service Provider

    Feb 1, 2009
    I’ve been testing some 15n20 pieces myself, and have not got the toughness I’ve heard so much about, these are impact and cut tests, including hammering through various mediums. Nowhere near what your doing! But in my testing, 8670 is holding up much better! Curious as to why they tested so low, considering the nickel content! It’s still an awesome steel, but not what I thought it was. I’m getting better edge retention, impact and lateral toughness out of 8670! I’m anxious to see how that tests out. Plus it’s cheaper.
     
  7. Mecha

    Mecha Madscienceforge.com Knifemaker / Craftsman / Service Provider

    Dec 27, 2013
    Isn't that just because they're hardened so much? I thought most steel types could be tempered to be tougher but softer.
     
  8. Larrin

    Larrin Gold Member Gold Member

    Jan 17, 2004
    One major reason is the high hardness, and they can indeed be tougher with lower hardness, generally. Another major reason is the presence of carbides.
     
  9. Mecha

    Mecha Madscienceforge.com Knifemaker / Craftsman / Service Provider

    Dec 27, 2013
    Ahhh the carbides. Makes sense - in titanium, just there mere presence of some alloying elements even at very low levels can make the alloy significantly more brittle or less tough, at any "hardness."
     
  10. kuraki

    kuraki Fimbulvetr Knifeworks

    Jun 17, 2016
    Charpy V is more for the type of steel I typically work with. A36, Gr50, Gr80, T1, etc. Things that wouldn't break without a V notch but would be worthless as a knife.
     
    hugofeynman, Mecha and Justin Schmidt like this.
  11. Mecha

    Mecha Madscienceforge.com Knifemaker / Craftsman / Service Provider

    Dec 27, 2013
    Cool info, I was only aware of the V-notch test, with large test samples. Larrin it would be cool to see some pics of the testing. :]
     
  12. Willie71

    Willie71 Warren J. Krywko. Part Time Knifemaker Knifemaker / Craftsman / Service Provider

    Feb 23, 2013
  13. Larrin

    Larrin Gold Member Gold Member

    Jan 17, 2004
    Alright!
     
    hugofeynman and Willie71 like this.
  14. MBB

    MBB Gold Member Gold Member

    244
    Apr 18, 2014
    Has 5160 already been done? How about the simple steels like 1075/1095 for comparison purposes? L6 and 9260 would also be interesting if available.

    Testing these is interesting if for no other reason than those are considered sword steels and thus are supposed to be extra tough.
     
  15. Willie71

    Willie71 Warren J. Krywko. Part Time Knifemaker Knifemaker / Craftsman / Service Provider

    Feb 23, 2013
    Big shoutout to Chuck at AKS who donated most of this steel for testing. (Some is my personal use steel.)
     
  16. Willie71

    Willie71 Warren J. Krywko. Part Time Knifemaker Knifemaker / Craftsman / Service Provider

    Feb 23, 2013
    Larrin, any plans to publish your results?
     
  17. Willie71

    Willie71 Warren J. Krywko. Part Time Knifemaker Knifemaker / Craftsman / Service Provider

    Feb 23, 2013
    I’m doing W2, and if I have a piece of 1095 left, I’ll do a sample of that too.
     
    hugofeynman and Justin Schmidt like this.
  18. Larrin

    Larrin Gold Member Gold Member

    Jan 17, 2004
    You mean other than on bladeforums?
     
    Justin Schmidt likes this.
  19. Willie71

    Willie71 Warren J. Krywko. Part Time Knifemaker Knifemaker / Craftsman / Service Provider

    Feb 23, 2013
    Yes, in a professional journal as examples of what can be done in “real world conditions” rather than with ideal equipment. It might be interesting to float this idea.

    Warren
     
  20. Tin.Man

    Tin.Man

    827
    Sep 5, 2010
    Would love to see some 1075 and 1084 compared to the tool steels and pm stuff as well. I have nothing to contribute but happy to donate to buy more steel
     

Share This Page