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Call for Charpy toughness samples

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

  1. Larrin

    Larrin Gold Member Gold Member

    Jan 17, 2004
    In another thread reporting some of our initial charpy toughness testing, we got a couple offers for samples for toughness testing. I would be happy to test more samples for the benefit of everyone. While we might not be able to test everything, I am open to taking more samples to compare. There is very little toughness data out there, especially when it comes to comparing between different manufacturers. I would not be charging for the toughness tests, but anything that we measure will be shared with others.

    The sample dimensions would need to be as follows:
    2.5 x 10 x 55 mm, with 55mm being in the rolling direction. Samples would have to be ground on the 4 main surfaces (less critical on the ends), and parallel, likely requiring a surface grinder or other precision machining tool.

    If anyone is willing to heat treat and machine samples for testing, please suggest in this thread what steel(s) and heat treatment(s) you would like to do. Everything we have done so far has had a liquid nitrogen treatment after quenching and prior to tempering so that we can eliminate the effect of retained austenite, so I would prefer that that step is added on other specimens, unless conditions both with and without cryo are provided.

    Current tests that have been performed:
    [​IMG]

    Ideal hardness is 60 Rc, even better is a range from 58-64 Rc. Steels we would like to add (incomplete list):
    M390/20CV at 60 Rc
    S30V
    S35VN
    S90V
    S110V
    Vanax
    Elmax
    440C
    ZDP-189
    Micromelt XHP
    Conventional XHP
    Conventional 154CM
    N690
    VG-10
    14C28N
    12C27
    Nitro-V

    3V
    4V
    Vanadis 4 Extra
    Vanadis 8
    10V
    CPM-M4
    M2
    A2

    52100
    O1
    1084
    1095
    15N20
    5160
    L6
    80CrV2
    O7
    1.2519
    1.2442
    1.2562
    F2
    Blue 1, 2, Super
    V-Toku 1, 2
     
    Last edited: Aug 25, 2018
    dirc, steff27, Mecha and 7 others like this.
  2. Darrin Sanders

    Darrin Sanders Knifemaker Moderator Knifemaker / Craftsman / Service Provider

    May 6, 2009
    Great news! I have a coupla questions. 1. What degree of finish/grit do the surfaces need? 2. Is a hole allowed for hanging by a wire and if so what would be the best location?
    Many thanks for offering this service.
     
    Tin.Man and Ken H> like this.
  3. Willie71

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

    Feb 23, 2013
    I’ll do z-wear and cast cru-wear for comparison in the three conditions Larrin suggested. Cryo plus low temper, no cryo plus high temper, and cryo plus high temper. Three samples of each condition.

    Larrin, how would you like them marked?

    Thank you so much Larrin.
     
    hugofeynman, Tin.Man and Ken H> like this.
  4. Larrin

    Larrin Gold Member Gold Member

    Jan 17, 2004
    The ASTM standards don't seem to have anything about required finish. All I have found is stuff about being free from machining marks or scratches. The samples so far were finished at 150 grit. A hole is allowed, it would need to be near the end of the sample as they break in the center.

    Edit: I found in the ASTM standard a requirement of 2 micron Ra, which is somewhere around 70 grit. Higher grit finish is better, of course.
     
    Tin.Man likes this.
  5. Larrin

    Larrin Gold Member Gold Member

    Jan 17, 2004
    Keep the different conditions in separate bags with an appropriate label. Include a sheet that includes all relevant details about the heat treatment of each.
     
    Tin.Man likes this.
  6. Darrin Sanders

    Darrin Sanders Knifemaker Moderator Knifemaker / Craftsman / Service Provider

    May 6, 2009
    Sounds good Larrin. As soon as I get a chance I'll get some done and grind them to 220. Would you mind sending me a PM including your address? Thanks again.
     
    Tin.Man likes this.
  7. Willie71

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

    Feb 23, 2013

    Sounds good. Looking forward to this. I’m putting in a steel order this weekend.
     
    hugofeynman and Tin.Man like this.
  8. Larrin

    Larrin Gold Member Gold Member

    Jan 17, 2004
    Sure, let's discuss in this thread what steels and heat treatments you would like to do. That way people can see what has been offered already. And if I decide not to test them I can say why for everyone to see.
     
    hugofeynman and Tin.Man like this.
  9. madcap_magician

    madcap_magician Platinum Member Platinum Member

    Feb 27, 2005
    I can't contribute, but thank you very much for this interesting and valuable research contribution.

    I'd be very interested in benchmarking results for common cutlery steels, especially, to give comparison data against all the exotics.
     
    Tin.Man and Justin Schmidt like this.
  10. Justin Schmidt

    Justin Schmidt Schmidt Forge Knifemaker / Craftsman / Service Provider

    Feb 18, 2016
    Very much looking forward to this. I was just having a conversation yesterday with someone about the toughness of aebl and how it compared to 3v. But he refused to believe how tough it was without charpy data of both. Looking forward to what steels are put up and how they preform. Exciting times. Hope someone does aebl, 3v, 52100, 1095, 80crv2, cruforge V. If i had the ability to heat treat and prepare these steels i would
     
    GABaus likes this.
  11. Natlek

    Natlek

    Jun 9, 2015
    Toughness is just one part of puzzles , valknut ;) Blade steel is always some kind of compromise ...........You can t get All in one ... sometime high wear resistance is more desirable ........ you always sacrifice something :)
     
  12. Larrin

    Larrin Gold Member Gold Member

    Jan 17, 2004
    As long as thy follow the simple specifications, whatever we test will be directly comparable to steels tested earlier, including AEB-L and Cruforge V.
     
    Justin Schmidt likes this.
  13. kuraki

    kuraki Fimbulvetr Knifeworks

    Jun 17, 2016
    My furnace is down at the moment but I should be able to submit 80crv2, W1, W2, 4v, M4, and Rex 121.
     
  14. Larrin

    Larrin Gold Member Gold Member

    Jan 17, 2004
    I hope you get the furnace back up soon!
     
    Justin Schmidt likes this.
  15. JTknives

    JTknives Blade Heat Treating www.jarodtodd.com Knifemaker / Craftsman / Service Provider

    Jun 11, 2006
    Hope I did not open a can of worms in the last thread with my question. I can send you a bunch of 15n20 samples at different hardness. But do you test hardness after the test or befor? It’s funny becaus I’m going to look at a surface grinder on Tuesday that I’m considering buying. Only problem is my 15n20 is only .090 thick, I can forge weld some togather but I’m wondering if that will affect the test results.
     
  16. Larrin

    Larrin Gold Member Gold Member

    Jan 17, 2004
    It’s possible that it will affect it of course, both in terms of your forging and heat treating procedure as well as the welding. It won’t be breaking along the weld, though, so that impact should be minimal.
     
  17. skillgannon

    skillgannon

    991
    Apr 27, 2009
    If someone wanted to set up a way that those of us who don't have equipment could chip in with cash I know that I would and I bet others also. Money could be used to purchase material or to help offset Mr Larren for his time and equipment. Good research is worth a lot.
     
    Tin.Man, Justin Schmidt and Willie71 like this.
  18. Larrin

    Larrin Gold Member Gold Member

    Jan 17, 2004
    I will not accept any money. If anyone wants to offer material, heat treatment, or machining that would be helpful.
     
    Justin Schmidt likes this.
  19. Larrin

    Larrin Gold Member Gold Member

    Jan 17, 2004
    The best way to do it is to test hardness with a sacrificial coupon heat treated along with the others. You can get away with hardness measurements on the ends, however.
     
    Willie71 likes this.
  20. Willie71

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

    Feb 23, 2013
    I’m good in terms of materials, heat treat, and shipping. I will need the surface grinding, but am exploring a couple leads on a that.
     
    hugofeynman and Justin Schmidt like this.

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