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Call for Charpy toughness samples

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

  1. rodriguez7

    rodriguez7 KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Feb 1, 2009
    What kind of controller do you have on you’re oven?
     
  2. Willie71

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

    Feb 23, 2013
    I think it’s called the rampmaster.
     
    rodriguez7 likes this.
  3. lazlo

    lazlo

    436
    Nov 23, 2006
    Hi Warren,

    I pointed out the same issue Willie is mentioning when Larrin posted this on Knifemaker's Whiteboard last week:

    The Crucible datasheet shows there's a massive dip in L6 toughness at 59 Rockwell. Which is the datapoint you have on your chart: 38 ft-lbs. :)
    According to Crucible's data (below), if you go down one point of Rockwell it jumps to 68 ft-lbs, which is off Larrin's chart for conventional steels.

    Also, which brand of L6 are you using? Crucible's Champalloy is quite different than Carpenters RDS. I can send you some Champalloy if
    that helps? A friend is talking to Tremblay about the L6 alloy they carry, but it's a German variant that has substantially lower carbon.

    Thanks!

    Robert

    [​IMG]
     
    ShannonSteelLabs likes this.
  4. Willie71

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

    Feb 23, 2013
    I did samples tempered at 350, 400, 450, and 500f. There should be harder samples in there. My stock was from NJSB, from about four or five years ago. No moly or vanadium.
     
  5. Larrin

    Larrin Gold Member Gold Member

    Jan 17, 2004
    I already explained in the Facebook group that our 38 ft-lbs is not equivalent to Crucible’s. They are two different specimen types.
     
    P.Brewster likes this.
  6. jdm61

    jdm61 itinerant metal pounder Knifemaker / Craftsman / Service Provider

    Aug 12, 2005
    BESTAR also sells that low carbon L6. IIRC, their stuff is around .55%.
    We have had some discussions in the past about that dip and the secondary hardening hump at 61Rc. I noticed that on a couple of different L6 tempering charts. From whatI recall, the hump is still there with the non-moly L6 like the RDS and whatever Hudson is selling. The tempering temperatures are lower. I think that with that stuff, 500F gets you into that peak range as opposed to 600F for the Champaloy type steel. There is another variant out there somewhere that Russ Andrews told us about which measures like Champaloy but with a litle bit of vanadium added. I think that is the stuff that ALRO sells line, but it is crazy expensive from what I can tell.
     
    Willie71 likes this.
  7. Willie71

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

    Feb 23, 2013
    I’ve got enough L6 for three or four more samples. I’ll wait to see what the other samples test at, and make higher or lower hardness samples as needed. I found more 0.120” 15n20 in a drawer too. I can run higher temper samples to see where embrittlement happens.
     
    hugofeynman likes this.
  8. hugofeynman

    hugofeynman

    539
    Jan 18, 2011
    That steel is like 1.2714 that Achim Wirtz sells. I have to settle some things first, but later I’ll buy a bar of this material (and 1.2241 (51crv4/6150)) and ship it to Warren (@Willie71).
     
    Willie71 likes this.
  9. rodriguez7

    rodriguez7 KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Feb 1, 2009
    I have the same. Still learning how to use it.
     
  10. lazlo

    lazlo

    436
    Nov 23, 2006
    Yup, that's the German L6 that Tremblay carries.
    Exactly. If Warren moves forward or back one point of hardness, he's out of the L6 dip, and I suspect it will be substantially higher toughness than 8670 on Larrin's chart. 8670 is a "light" version of L6.
     
    Kentucky likes this.
  11. lazlo

    lazlo

    436
    Nov 23, 2006
    Ah! That would be very interesting to see Warren -- thanks! :)

    I'd be glad to make you a set of samples of Crucible Champalloy, which the Grandmaster's of L6: Kevin Cashen, Howard Clark, .... recommend as the good stuff. I can heat treat it as well, if you'd like - I have all the equipment (Paragon, Wilson Rockwell tester, ...).
     
    Last edited: May 23, 2019
    hugofeynman likes this.
  12. Willie71

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

    Feb 23, 2013
    Please do! The samples need to be 55mm. x 10mm 2.5mm, after decarb is ground off. 3 samples per heat treat condition. If you don’t have a surface grinder, make them a bit oversize, and they can be ground by one of the volunteer grinders.
     
    hugofeynman likes this.
  13. Willie71

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

    Feb 23, 2013
    When programming, set the number of temps you want, next is the ramp speed, 9999 is fastest, then set the temp, then the hold time, repeat for each temp. Press program, then the number that program is assigned to. For me ramping is #2. #1 is a single temp cycle.

    Yesterday I set program 2, 3, enter,9999, enter, 1450, enter, 1.00, enter, 9999, enter, 1850f, enter, 0.30, enter, 9999, enter, 1900, enter, 0.30, enter. I think you press program once more, then enter iirc. I’m not in front of it right now. You should heat the thermocouple/controller click, then the readout says run.

    It takes about 30 seconds to set once you are familiar.
     
    rodriguez7 likes this.
  14. rodriguez7

    rodriguez7 KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Feb 1, 2009
    Sweet, thanks. It can get complicated. And I’m still learning it. Some people said the tap controller is actually better, and simpler. But I’m learning this one. The other day, I set up A8 mod similar to what you just typed, with different hold times and temps. And I’m doing all my tempering in this oven too.
     
    Storm W and Willie71 like this.
  15. Kentucky

    Kentucky KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider Basic Member

    Dec 13, 2008
    I’ve welded L6, 8670 and 5160 bits in axe heads many times. In my tests at around 56-57rc there’s no comparison. L6(champaloy, I also have the old Republic L6 which is close to champaloy with Moly)) was much tougher than the other two. Though I’m sure my tests were less scientific and I was testing axe bits)
     
    lazlo likes this.
  16. shqxk

    shqxk

    Mar 26, 2012
    This does sound ridiculously ignorant.

    What's wrong with HT M4 in Evenheat? Do you even have a clue there are many type of Evenheat and some of them can goes above 2200F easily...

    These kind of compact kiln can heat to very high temperature with very accurate temperature control and allow user to apply precise soaking time (very important for stainless damascus) and easier to use faster quench rate. In conclusion, with a good kiln, you can even get better overall result compare to commercial vacuum furnace if you know what you are doing.
     
    Last edited: Jun 8, 2019
    Storm W, samuraistuart and Ocelot85 like this.
  17. cotdt

    cotdt

    Oct 2, 2006
    My Evenheat has no trouble getting to 2200F. Takes about 50 minutes though. No problem with CPM M4.
     
    Storm W and Ocelot85 like this.
  18. Natlek

    Natlek

    Jun 9, 2015
    Yes , you're right .I apologize ! :thumbsup: There was many topic on blade forum to prove that . Fifteen bricks + HT element make Evenheat best HT oven ,they have an unbelievably uniform temperature , they can go above 2200F ...What can I say , they are best especially for science experiment . You forgot toaster oven ...yes they are best for tempering ................:poop:
     
  19. DeadboxHero

    DeadboxHero Triple B Handmade Knives, Big Brown Bear

    Mar 22, 2014
    My Evenheat is working just fine.

    It's the sum of all parts combined with skill, experience and knowledge, not just fancy tools.

    A fancy furnace doesn't guarantee anything and arbitrarily hitting 2200 for M4 doesn't guarantee performance either.



     
  20. Boru13

    Boru13 Super Moderator Staff Member Super Mod Moderator Pirate

    843
    Apr 25, 2000
    Warning issued for trolling, put an end to it please.
     

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