What steels can I harden with a gas forge

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    • At the moment I only have a gas forge and it will be a long time before I have anything better. I have hardened o1 and 52100, but would like to use different steel types. I would like to know what steels others have heatreated with just gas forges and what the process is. I am interested has any one been able to get good results with stainless knife steels?
      Any info any one?

  • I've only used O1 in a propane forge, would like to try a stainless steel but am put off by the need for liquid nitrogen or dry ice to complete the HT process, to obtain the steels full potential. Have you thought about that aspect William??

  • I've only used O1 in a propane forge, would like to try a stainless steel but am put off by the need for liquid nitrogen or dry ice to complete the HT process, to obtain the steels full potential. Have you thought about that aspect William??

    this is my concern too. Please tell me otherwise though, I'd love to play with a bit of stainless.

  • Cryo is not needed to ht most stainless But it will up the rc by a point or two to a finish blade.it will also add some toughness.Many maker including farid who told me this the other day have never used cryo.
    Personally I do use it just because I want to but I use dry ice.
    Holding a temper for a set period in a controlled atmosphere is a must and a gas forge will be very hard to use.
    Example I have some cpm10v atm and you have bring it up to a temperature then hold and then go to another and hold for a long period.
    This would be hard/impossible in a gas forge imo.

  • Thanks for the suggestions I've bought a infrared high temperature thermometer to help, so I know what temperatures I'm getting. Previously I was using colour and whether or not it was metallic. I will have a play around and see how accurate I can be at holding temperature before I consider givimg some stainless a go.
    Cheers

  • Which ever heat source is used, I'd like to see someone make two identical knives but only cryo one of them, then do some real world testing of both.


    A pass around would be a nice opportunity, to see if many folk could actually notice the extra rc or any sharpening/blunting issues.


    These knives don't need to be anything fancy, just different coloured handles or marked in such a way that only the maker knows which is which,.....answers only posted after others had their guess/opinions on which is which. :)

  • @earthman that would be a good fun idea.But I don't think anyway would argue the fact that cryo benefits some steels.A 61rc knife with cryo is as hard as a 61rc without. Its just a cryo treatment will be a more stable 61rc in its grain structure and will have very little RA left over.
    it would be interesting to see if anyone could tell the difference in a point Rc. I notice nothing much at all between a 59rc and a 60rc of the same steel.

  • @earthman that would be a good fun idea.But I don't think anyway would argue the fact that cryo benefits some steels.A 61rc knife with cryo is as hard as a 61rc without. Its just a cryo treatment will be a more stable 61rc in its grain structure and will have very little RA left over.
    it would be interesting to see if anyone could tell the difference in a point Rc. I notice nothing much at all between a 59rc and a 60rc of the same steel.


    I'm wondering if there has ever been any lab testing at least? I'm guessing that there must have been but does it really make any difference to the end user or is it just an excuse to add another element/charge for the process?


    Until I see some real life testing/hear or results from others, I'm kind of on the fence to be honest.

  • Cryo can have a high start up costs, a dewar is £300-£400 and LN refills are around £50 depending on your location but can last up to 6 weeks so you can do quite a lot of knives if you are organised.


    I always cryo stainless and D2 and O1 if the client wants it. I don't see the point in using good steels like RWL 34 or CPM 154 and skipping on a stage that gets the very best out of them.

  • I wonder if some clients ask for it just because they've heard it mentioned/it's the latest craze sort of thing.


    Similar to the hype for using 'Super unleaded' petrol, yes in the right engine, under lab conditions there probably is a difference but in a 'normal' car during normal driving conditions, I'm buggered if I can tell the difference.