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  1. #1
    Senior Member
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    how do you prevent warping

    When heat treating thin blades.

    Im thinking of stainless warping during heat treatment. Whats the thinnest you "dare" to grind befor heat treating? Any advice you can give on how not to warp.

    The steel "we" tried was rwl-34 (CPM154, ats-34).
    "If you are flamable and have legs you are never blocking a fire exit."

  2. #2
    Why do you need to pregrind deep hardening steel? Hardened steel is just a little bit harder to grind than unhardened, and grinding introduces stress in the steel and a possibility of warping during heat treating.

    Pick the thickness that is close to the final thickness. Heat treat a blank in a full thickness, aluminum plate quench, temper and then grind. Do a cryo quench if you have a capability. Use good quality ceramic abrasives belts. They will remove metal efficiently while keeping it cool (you will need to dip your blank in a bucket of water periodically)

    M


    "If there’s something worth doing, it’s worth overdoing.” - An US saying.

    If my KKF Inbox is full (or not), please contact me via Email: anvlts@gmail.com

  3. #3
    Quote Originally Posted by Marko Tsourkan View Post
    Why do you need to pregrind deep hardening steel? Hardened steel is just a little bit harder to grind than unhardened, and grinding introduces stress in the steel and a possibility of warping during heat treating.

    Pick the thickness that is close to the final thickness. Heat treat a blank in a full thickness, aluminum plate quench, temper and then grind. Do a cryo quench if you have a capability. Use good quality ceramic abrasives belts. They will remove metal efficiently while keeping it cool (you will need to dip your blank in a bucket of water periodically)

    M
    +1

  4. #4
    Quote Originally Posted by Marko Tsourkan View Post
    Why do you need to pregrind deep hardening steel? Hardened steel is just a little bit harder to grind than unhardened, and grinding introduces stress in the steel and a possibility of warping during heat treating.

    Pick the thickness that is close to the final thickness. Heat treat a blank in a full thickness, aluminum plate quench, temper and then grind. Do a cryo quench if you have a capability. Use good quality ceramic abrasives belts. They will remove metal efficiently while keeping it cool (you will need to dip your blank in a bucket of water periodically)

    M
    Marko, do you have any suggestions as to where one might find a wide variety of thin stock? It seems that the field and camp knife folks think that .15" is pretty thin.

  5. #5
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    Thanks Marko, do you know where i can get some more info about plate quenching?
    "If you are flamable and have legs you are never blocking a fire exit."

  6. #6

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    Aldo has .103 stock in a lot of the steel he carries, which is like 3/32 with a little extra meat on it. On some of the CPM stuff, he has stock as thin as .062.

  7. #7
    Admiral steel has Sanvik variants in several thicknesses.

    Aluminum plate quenching is basically using two thick aluminum plates (I use 1" thick) to cover the blank (one on the bottom, one on the top) for fast and efficient cooling. It helps a lot with keeping a blank straight. Search youtube or google to find more on the subject.

    You can also try to straighten a warped blade using this method:
    http://www.bladeforums.com/forums/sh...ing-The-Temper

    M


    "If there’s something worth doing, it’s worth overdoing.” - An US saying.

    If my KKF Inbox is full (or not), please contact me via Email: anvlts@gmail.com

  8. #8
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    Quote Originally Posted by Marko Tsourkan View Post
    Pick the thickness that is close to the final thickness. Heat treat a blank in a full thickness, aluminum plate quench, temper and then grind. Do a cryo quench if you have a capability. Use good quality ceramic abrasives belts. They will remove metal efficiently while keeping it cool (you will need to dip your blank in a bucket of water periodically)
    Done a lot of reading tonight =), just to clarify HT -> plate quench, temper -> cryo quench? And if it still warps use the clamp temper method. If i get it i should interupt the tempering befor it reaches the right temp and tighten the clamps? then temper and then quench, perhaps in sub zero?
    "If you are flamable and have legs you are never blocking a fire exit."

  9. #9
    Quote Originally Posted by toek View Post
    Done a lot of reading tonight =), just to clarify HT -> plate quench, temper -> cryo quench? And if it still warps use the clamp temper method. If i get it i should interupt the tempering befor it reaches the right temp and tighten the clamps? then temper and then quench, perhaps in sub zero?
    Always cryo before tempering. Are you going to try RWL-34 again? You might check their website for heat treatment temp recommendation of give them a phone call. Sometimes they specify how long to cryo quench.

    It you don't pregrind, and you plate quench, you should have no problem with warping. If for some reason you do, you can over-clamp it during tempering to straighten the blank. A little bit of warping can be ground out as well.

    M


    "If there’s something worth doing, it’s worth overdoing.” - An US saying.

    If my KKF Inbox is full (or not), please contact me via Email: anvlts@gmail.com

  10. #10
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    The "plan" is to stick with RWL-34. I spoke with them a couple of days ago about forging the steel due to the size, they have 50mm standard i need 55 =/. Aperantly its quite sensitive about overheating but they say no problem with forging. They also recommend low temp HT with cryo for the steel to be less sensitive to corrosion but still quite hard.

    Cryo seem to be done for 10min but at what stage should i plate quench? shall i HT then cryo im a bit confused now (as usual)

    Thanks for your advice Marko
    "If you are flamable and have legs you are never blocking a fire exit."

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