A2 vs D2 steel blanks

Discussion in 'Edged Tools' started by krismorgan, Oct 12, 2018.

  1. krismorgan

    krismorgan Supporter Supporter

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    0C00ED99-145F-47FF-A6FA-2E7693EDC3CD.jpeg A friend of mine worked at a machine shop that closed up shop and he had some A2 and D2 steel blanks. Problem is that he can’t remember which pieces were which steel. Any knowledge on how to differentiate the pieces? They are all in an annealed state.
     
  2. MichaelBear

    MichaelBear Bushmaster

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    A2 will rust faster as D2 is semi stainless. From the photo it appears that two or three from the right could be D2. Also, A2 should be little softer under the file in annealed condition than D2. You can clean the blanks some and add drop or two of water and wait a bit. Usually takes less than 1 hr with tool steel to show. D2 may not get stained that easily.
     
  3. krismorgan

    krismorgan Supporter Supporter

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    Great info! I will try it! Thank you
     
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  4. krismorgan

    krismorgan Supporter Supporter

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    EF9B7085-5B57-40D1-97C6-3450DB074ECE.jpeg Test es no bueno. All rusted the same
     
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  5. NevadaBlue

    NevadaBlue Graybeard Supporter Bushcraft Friend Bushclass I

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    Do you know anyone with a nuclear tester? I used to buy steel at a surplus place and they tested everything and marked it.
     
  6. krismorgan

    krismorgan Supporter Supporter

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  7. blue333

    blue333 Supporter Supporter

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    I know they make small(ish) file sets that have a Rockwell progression. I would imagine you can check the hardness differences? D2 is harder of the two, but not sure if your piecese are tempered/annealed or raw? Other than what was mentioned above, this is all I could think of?
     
  8. JollyRoger3

    JollyRoger3 Guide

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    Clean off a section of each bar, Boil up some white vinegar. Dip the cleaned steel in the vinegar, whichever takes the patina first is A2. The A2 will patina in seconds.
     
  9. CoolBreeze135

    CoolBreeze135 Scholarly Woodsman Supporter

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    This is probably the best shot you have. D2 is quite a bit more stain resistant, so rate of patina should be a semi reliable way to differentiate.
     
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  10. MichaelBear

    MichaelBear Bushmaster

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    That's interesting. All started developing spots at the same time?
     
  11. krismorgan

    krismorgan Supporter Supporter

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  12. krismorgan

    krismorgan Supporter Supporter

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    C24F6F9E-559E-45BE-806B-6F3ED4333D6D.jpeg Vinegar test
     
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  13. krismorgan

    krismorgan Supporter Supporter

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    I am at a loss. Rusted the same. Vinegar test looks the same. File to the corner was the same.
    Maybe it’s a duck!!!!
     
  14. BradGad

    BradGad Supporter Supporter

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    So maybe your buddy used up all of one or the other, and what’s left is all A2 or D2.

    If the A2 patinas in seconds like JollyRoger says (I wouldn’t know), then the time it takes them all to show reaction may answer the question.
     
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  15. riokid87

    riokid87 Scout

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    A2 will mirror polish much better as d2 looks a little orange peel.
    Do the ends have any paint on them? Same color likely same steel.
     
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  16. krismorgan

    krismorgan Supporter Supporter

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    I agree that maybe he used all of one steel...but he’s a pretty common sense guy and usually spot on. That being said, 4 blues, 1 green, 1 no color
     
  17. krismorgan

    krismorgan Supporter Supporter

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  18. MichaelBear

    MichaelBear Bushmaster

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    Yeah, well, vinegar is acid so no duh hehe. Water is much slower process hence if you watch is carefully it may show which would start rusting first, however, from what those photos it seems you have tool steel. Green is used to mark D2 like on njsteelbaron web. I'd say you have A2 in the other bars or something else depending if you want to judge by color or not. That's a tough one since different suppliers use different color codes. Maybe ask where he got the steel from.

    http://newjerseysteelbaron.com/shop/product-category/tool-steel/
     
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  19. krismorgan

    krismorgan Supporter Supporter

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    I was thinking like you were with the colors. My only issue at this point is that I want to sell or trade and don’t want to sell the steel as something that it isn’t....nor do I want to over or undersale it. I don’t have the capability to heat treat either steel in house so I was gonna let them go
     
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  20. x39

    x39 Hyperborean Supporter

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    Unfortunately, if you're not SURE of the provenance, it really isn't worth much at all.
     
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  21. krismorgan

    krismorgan Supporter Supporter

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    True. But I’m not sure that any knife is any material other than someone telling me what they used to make it....I have no way to test it. I am trusting what someone tells me such as is the situation I am in now.
     
  22. x39

    x39 Hyperborean Supporter

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    You have to decide what your own ethics are.
     
  23. krismorgan

    krismorgan Supporter Supporter

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    lol. I know what my ethics are. That’s why I am asking the questions and put my sale on hold on the trade forum. Check it out
     
  24. Coryphene

    Coryphene Guide

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    Can cut off a little coupon and heat up and quench then spark test. D2 doesn't like to spark as it has so much chromium but A2 showers sparks readily. If they all spark nicely, then I think you have A2.

    The real worry is if you make blades then send off to heat treat and tell them it is A2 but is really D2, they will give vastly different results as the heat treatment for both is much different.
     
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  25. x39

    x39 Hyperborean Supporter

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    Okay, hope you get it figured out.
     
  26. Kyle363

    Kyle363 Supporter Supporter

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    Maybe they're all the same steel. D2 shouldn't rust like that.
     
  27. DrunkenMarmot

    DrunkenMarmot Tracker

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    +1 on the spark test suggestion... (w/ camera also a good idea). lots of info/pics online for that as well for comparison.
     
  28. 556mp

    556mp Bushwhacker Vendor Bushclass I

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    Depending on how much you actually have, you can send it out to a lab for testing. It's probably about $250, but if you have $1000 worth of free steel, it may be worth it. If you are just going to be making some knives for yourself and not to sell, the heat treatment is similar-ish and in real life, you probably wont even notice a difference. As others have said, spark testing can give a little insight into what is going on, and it's free.
     
  29. x39

    x39 Hyperborean Supporter

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  30. USMCPOP

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    Unfortunately, steel suppliers do not use standard color codes, though I have seen a few charts that used blue for D2. The same colors can be used for different classes of steel as well (carbon vs tool steel vs low alloy ...).

    One guy at Practical Machinist asked about color codes, and came up with a chart for their shop:

    RED- means nothing
    BLUE- means anything
    GREEN- means go
    BLACK-means disregard
    YELLOW- means put the pedal to the metal
     
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  31. riokid87

    riokid87 Scout

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    The color may not I'd what steel, but if the are from same place all the same color should be the same. Since he has 2 steels, 4 blue, 1 another color and one unmarked, it's likely the 4 blue are either a2 or d2, the green the other, and the blank still unknown. I would make a small knife from the blue and heat treat it like a2 then polish it. If you get a bright clear mirror reflection it's a2. If not then it's d2, normalize and re heat treat it as d2.
    1 more thought, when I bought a2 it came with a finish that was called pickeled, it looks like it sounds. Supplier had an option to surface grind it off for a fee but if one has it and the other doesn't that may be a clue. Idk if d2 pickles too.
     
  32. S.Gossman

    S.Gossman Guide Vendor Supporter

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    If the steel is Precision Marshall from Clark and Osborne then blue marked is A2 and green marked is O1. D2 has 11% chromium. It still can rust but not as easily as the others. I'll have to check what color D2 is marked. D2 is marked white.
    Scott
     
    Last edited: Oct 17, 2018 at 11:10 AM
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  33. krismorgan

    krismorgan Supporter Supporter

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    The man at the supply house where the steel was purchased from mentioned precision Marshall. He actually called them for me to verify the colors and you are correct. I am selling the A2 on the trade blanket and keeping the 01 I got
     
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  34. S.Gossman

    S.Gossman Guide Vendor Supporter

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    Very good. At least you now know what you have.
    Scott
     
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