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  1. #11
    Canada's Sharpest Lefty Lefty's Avatar
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  2. #12
    WillC's Avatar
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    Got these two ht'd, cryo'd and first temper cycle, two more full hour temper cycles to go. With forging more complex steels, makes the pre-heat treatment and heat treatment processes take much longer. The anneal cycles were 3 hours and cool in furnace, so basically 2 days of annealing before HT can begin.

    I also did a billet in plain stainless clad D2 as it was the perfect test for my new furnace, very narrow temperature band for success, it was a success A bar of 12mm x 50 x 1000 cpm 3V is on its way to me from germany.

  3. #13
    Senior Member Mucho Bocho's Avatar
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    Looking good Will. Some day I'll understand how all the processes come together annealing, tempering, forgiving, cryo...
    One thing you can give and still keep...is your word.

  4. #14
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    Quote Originally Posted by Mucho Bocho View Post
    Looking good Will. Some day I'll understand how all the processes come together annealing, tempering, forgiving, cryo...
    Forgiving is my favorite step.

  5. #15
    WillC's Avatar
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    In simple terms
    The main reason to heat cycle and anneal after forging is that the grain structure will be very large and crystalline after heating it up to welding temperature, then forging. Also during forging it may have become somewhat hardened, these are air cooling steels in this instance, so it is hard to avoid. The heat cycling reduces the grain size and removes stresses, Annealing ensures that it is in its fully un-hardened condition.
    Now you have a piece ready to heat up to critical temperature and quench to harden, in oil or air. In this case I used my hydraulic press to plate quench the blades, the plates under pressure take the heat quickly from the blade and this also helps keep it straight as a bonus.

    After this you have cryo treatment - Short answer this helps you achieve greater hardness, especially in stainless and not at the expense of toughness.... and tempering, Tempering takes some hardness from the steel to ensure a good balance of toughness. In this case triple tempering is also shown to help reduce carbide size....therefore giving greater toughness at a given hardness......

    Looking forward to testing these blades now........... Will have to wait till next week

  6. #16
    WillC's Avatar
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    You should always forgive the steel, as its much harder than you.

  7. #17
    Senior Member chinacats's Avatar
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    Quote Originally Posted by WillC View Post
    In simple terms
    The main reason to heat cycle and anneal after forging is that the grain structure will be very large and crystalline after heating it up to welding temperature, then forging. Also during forging it may have become somewhat hardened, these are air cooling steels in this instance, so it is hard to avoid. The heat cycling reduces the grain size and removes stresses, Annealing ensures that it is in its fully un-hardened condition.
    Now you have a piece ready to heat up to critical temperature and quench to harden, in oil or air. In this case I used my hydraulic press to plate quench the blades, the plates under pressure take the heat quickly from the blade and this also helps keep it straight as a bonus.

    After this you have cryo treatment - Short answer this helps you achieve greater hardness, especially in stainless and not at the expense of toughness.... and tempering, Tempering takes some hardness from the steel to ensure a good balance of toughness. In this case triple tempering is also shown to help reduce carbide size....therefore giving greater toughness at a given hardness......

    Looking forward to testing these blades now........... Will have to wait till next week
    Thanks, I needed that!
    one man gathers what another man spills...

  8. #18
    Senior Member Mucho Bocho's Avatar
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    Thanks Will for taking the time to explain that. I've got to get over there, my buddy lives in Worchester and has been telling me for years to come and visit.
    One thing you can give and still keep...is your word.

  9. #19
    WillC's Avatar
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    Worcester? Only about half an hour from my workshop.
    Here is a good paper on Metallurgy for bladesmiths.
    http://www.feine-klingen.de/PDFs/verhoeven.pdf
    I often refer to this as I could never remember it all, well maybe one day. I have not really that type of brain, I just like to know enough to get a feel for what Im doing and take it from there with some real world tests. Where as the science would explain what is happening during the processes and transformations, in general I only wish to know what will achieve the best results, though I can see how a greater understanding of the chemistry can help so i do try to understand.
    There is a great chapter on AEB-L in the above.

  10. #20
    WillC's Avatar
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    This is the paper I read on getting the best toughness and as fine and even distribution of carbides in D2 as possible.
    https://tspace.library.utoronto.ca/b.../1/MQ45596.pdf

    I will be interested in the results in terms of a kitchen knife because that is my field of comparison with everything else in terms of how it sharpens, how sharp it gets, how the edge feels to the touch and in cutting and edge retention. Im sure it will be tough at this HT. D2 has been reported as many things, hard to sharpen, very toothy, tough, chippy. There is allot in a heat treatment for sure.
    I hope with this heat treatment, I will have an optimum level of the toothy character of the steel, but tough with no microchipping, easy to sharpen, relatively fine edge. Its never going to be as fine and get as sharp as a super fine carbide steel like AEB-L or 14c28n, but I'm going for a different effect here, some teeth and an increase in wear resistance over fine carbides. For a real hard wearing slicer, that retains its teeth long after loosing the shine from the strop.
    Will be very interesting to compare to cpm 3v, which should be a very tough steel also with good wear resistance, but with finer carbides, given correct treatment. So they should feel and cut slightly different. There are a few others I would like to try. None are particularly in the super wear resistant area. I might play with this later, but at the moment Im interested mostly in steels which are at least relatively easy to sharpen and work with.
    Something like cpm 10v is an interesting proposition but poses issues in all areas as far as forging, grinding and maintaining a knife made from it.

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