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Thread: Looking for the best heat treatment for O1

  1. #71
    Senior Member gregg71's Avatar
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    Sorry guys, I was stupid. I strongly trusted in screen of the oven. This is a small oven with specialities like powerlessness. I have done some test, you can see below the result.

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    A corrected my previous values.

    First attempt
    edge 0.5 mm
    normalizing: 805(905-950)C, 3 times
    soaking: 805(905-950)C, 15 min.
    quenching oil: 80C, 5-10 sec
    tempering: after cooling to room temperature, 200 C, 2x1h (between cooling to room temperature)

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    Second attempt
    edge 1 mm
    normalizing: 790(890-940)C, 3 times
    soaking: 790(890-940)C 15 min.
    quenching oil: 70C, 30 sec.
    tempering: after cool enough to touch, 220 C, 2x1h (between cooling to room temperature)

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    Third attempt (a second time HT)
    edge 0.5 mm
    normalizing: 800(900-950)C, 3 times
    soaking: 800(900-950)C, 15 min.
    quenching oil: 50C, 10-15 sec.
    tempering: after cool enough to touch, 200-205 C, 2x1h (between cooling to room temperature)

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    Heat treated razor by a hungarian knife maker
    His oven the same as me. The staining caused by water

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    Professional heat treating

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    ....

    Seventh attempt
    normalizing: none.
    soaking: ~805C, 15 min.
    quenching oil: 50C, 10 sec.
    tempering: none

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    I learned a lot from this. Thank you everyone for your help!
    Last edited by gregg71; 02-19-2015 at 06:19 PM.
    gregg

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    ScottGoodman (02-25-2015)

  3. #72
    Senior Member PierreR's Avatar
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    There you go! That looks like a fine grain structure!
    spazola likes this.
    My friends call me Bear.

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    gregg71 (02-24-2015)

  5. #73
    Senior Member gregg71's Avatar
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    Yes, it seems. I am happy with it. I will change my thermocouple and make a complete HT. I hope...
    gregg

  6. #74
    Member Gomerpile's Avatar
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    I wish I were having your troubles right now Gregg. I will one day attempt my own heat treating and when I do, I will remember some of these lessons. I have learned so much from your adventure and happy things worked out so well for you.

    Thak you for your patience and determination!

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    gregg71 (02-24-2015)

  8. #75
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    So you were accidentally austenizing at a temp 100C higher than the correct one? Well,that would certainly explain the beach sand sized grain!!!!! That last one looks pretty much spot on.

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    gregg71 (02-25-2015)

  10. #76
    Senior Member gregg71's Avatar
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    Quote Originally Posted by JDM61 View Post
    So you were accidentally austenizing at a temp 100C higher than the correct one?
    Exactly.
    gregg

  11. #77
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    Mr.Blue and some others could speak to this better than I, but the info that I have always been given is that the grain size blow up starts at temps above 1600F or around 871C for the kind of carbon/tool steel that we are discussing unless you have a steel with enough vanadium in it to delay that growth a bit and even then, it will still not be ideal. When guys over here do an initial "normalizing"cycle on spheroidized 52100 to break up the carbides and get stuff in solution, the do it at around 1650F or 898C. The DO get grain growth, but they count on the subsequent lower temperature thermal/normalizing cycles to take care of that. Sounds like you were growing grain at almost eve step of the process.
    Quote Originally Posted by gregg71 View Post
    Exactly.

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    gregg71 (02-25-2015)

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