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Call for Charpy toughness samples

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

  1. hugofeynman

    hugofeynman Gold Member Gold Member

    576
    Jan 18, 2011
    Can’t wait for the tests to proof your impressions! A Ztuff coupon heat treated to max toughness (will probably have a lower hrc reading than 61) should be even higher on toughness than the ones Larrin tested so far!

    So: Ultrafort, S7, NZ3 (~S1), 1v, Ztuff (tempered to achieve max toughness) and A8mod are the top contenders to steal the 8670 crown.:)
     
    Last edited: May 13, 2019
    Tin.Man likes this.
  2. Tin.Man

    Tin.Man

    827
    Sep 5, 2010
    Funny I'm working in a batch of Pugio, and a Pompeii style gladius and the whole batch is a8mod
     
    hugofeynman likes this.
  3. hugofeynman

    hugofeynman Gold Member Gold Member

    576
    Jan 18, 2011
    Great steel choice, @Tin.Man!
     
  4. Salival

    Salival

    68
    Apr 9, 2014
    I really think 6150 can be on top too. I have done bad things to my ztuff knife this days and it has not taken less dmg than 6150. (BTW keep your knives away from construction nails and screws... )
    Giedy also told me that his 6150 is a bit tougher than nz3.
    I will ask him if he can send a sample.
    I'm working with him with 2 new blades, let's see what he says.
     
  5. hugofeynman

    hugofeynman Gold Member Gold Member

    576
    Jan 18, 2011
    Please convince him to do so! I already gave Warren and Larrin a piece of NZ3 from another Polish maker (LKW Knives, a gentleman to deal with), now we need 6150 also! And if it’s even tougher than NZ3 (he’s right, less carbon should make 6150 tougher than NZ3 and 5160), let’s bring it to the test!:D
    If he doesn’t have the time to make the coupons, ask him if he can donate a piece of steel big enough to, at least, three coupons (cut parallel to the rolling direction of the steel).
     
    Salival likes this.
  6. Willie71

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

    Feb 23, 2013
    I got the 1v and s7 this week. Thanks Scott! I’m home for the weekend, so hopefully I’ll run through a bunch of samples.
     
  7. Gossman Knives

    Gossman Knives Edged Toolmaker Knifemaker / Craftsman / Service Provider

    Apr 9, 2004
    Awesome Warren. Glad to help. Look forward to your results.
    Scott
     
    Willie71, hugofeynman and Larrin like this.
  8. Willie71

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

    Feb 23, 2013
    If you have a protocol you want tested, pm it to me, and I’ll follow it.
     
    hugofeynman likes this.
  9. jdm61

    jdm61 itinerant metal pounder Knifemaker / Craftsman / Service Provider

    Aug 12, 2005
    So it sure lookalike the old theory that says that 52100 and AEB-L are pretty similar in use seems to be accuarate.
     
    Willie71 likes this.
  10. Willie71

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

    Feb 23, 2013
    Wait until we see 15n20. I’ve said for years it’s like non stainless aeb-l. 8670 is better than I expected too.
     
    P.Brewster likes this.
  11. hugofeynman

    hugofeynman Gold Member Gold Member

    576
    Jan 18, 2011
    According to Crucibles data sheet (or my interpretation of those values:p), a good starting point would be: 1725F 30 min soak and 400F temper (two hours(???), two tempers(????)). That should put this steel right in his toughness peak and with an interesting hardness value (57). Because we are reaching max toughness, I would avoid cryo. I’m sure RA% with this steel would not be a problem, this thing is designed to use low temper protocols, not “forced” to be low tempered, as we like to do nowadays to some pm steels.;)
     
  12. hugofeynman

    hugofeynman Gold Member Gold Member

    576
    Jan 18, 2011
    Have you bought your Ztuff knife overseas? Who was the maker? Not usual to see that steel used in Europe.
     
  13. jdm61

    jdm61 itinerant metal pounder Knifemaker / Craftsman / Service Provider

    Aug 12, 2005
    The two issues that I see with the 8670 is lack of larger stock and the idea that you don't seem to be able to run up the hard
    ness like you can with 52100, AEB-L, CFV and from what I have heard, 15N20. L6 typically has that second "hump" at 61Rc wherein is like 85% or so as tough as it is at 57Rc. I an wondering of the L6 that was test was in that "dip" between those two peaks.
     
  14. jdm61

    jdm61 itinerant metal pounder Knifemaker / Craftsman / Service Provider

    Aug 12, 2005
    That's weird because it is made by Zapp in Germany. It may be just not be commonly used for knives anywhere yet.
     
    hugofeynman likes this.
  15. Willie71

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

    Feb 23, 2013
    I’ve made a few kitchen knives in 8670 at Rc63, and they perform quite like 15n20.

    I’ll check the L6 samples, and see if I did higher hardness samples. I have one piece left here, and can push the hardness up.
     
  16. jdm61

    jdm61 itinerant metal pounder Knifemaker / Craftsman / Service Provider

    Aug 12, 2005
    I was just going by the drop off that we saw in the testing of the 8670. Maybe higher AND lower for the L6.. The max hardness on the charts is like 57-58, shined towards 57 and then that second hump is at like 61, BUT there is an actually dip on the chart between like 58 and 60.
     
  17. Alpha Knife Supply

    Alpha Knife Supply Always Innovating Dealer / Materials Provider

    Oct 14, 1998
    What thicknesses are you looking for? We have .084", .102", .126", .138" .170", .186", .210" & .224" in stock. We have a chef knife that is HRC 62 that hammered through steel tubing with no damage to the edge.
    Z-Tuff was designed by the same metallurgist who invented CPM 3V. He works for Zapp here in the US. The powdered billet was made by Carpenter for Zapp so it was made with the super fine powdered metal. It is designed and made here in the US. We just received our shipment of .098 Z-Tuff.

    Chuck
     
  18. jdm61

    jdm61 itinerant metal pounder Knifemaker / Craftsman / Service Provider

    Aug 12, 2005
    Ah. I did not know that about the manufacturing of Z Tuff although I had heard that the metallurgist who gave us 3V also gave us this cool stuff. As for the 8670, this is first that I have seen of stock thicker than like .1875. Good work once again!!!!!!! Still a little thin for tactical tomahawks perhaps. ;) I may have to score some of tha .098 for something like a thin Kephart. Who has the recipe for the HT? From what I saw, Zapp seems to suggest a fairly complex process so I am not inclined to try it in my Paragon.
     
  19. Willie71

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

    Feb 23, 2013
    1900fx45min, plate quench, cryo, 400 temper x2. Gives you Rc60. 1950 30 min, cryo, 400fx2 gives you Rc61/62. Rc62 seems to be where it tops out. It’s more sensitive to tempering temps than other similar steels. The tested sample was 1925f, cryo, 300f temper for Rc61.5.
     
    Last edited: May 18, 2019
    rodriguez7 and hugofeynman like this.
  20. hugofeynman

    hugofeynman Gold Member Gold Member

    576
    Jan 18, 2011
    Only now I’ve realized that Zapp is a German company! I thought it was based in US!

    Although Ztuff is from Germany, never heard about European makers using that steel.
     

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