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Case hardening how to?

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  • Case hardening how to?

    So I have some little parts I want to try case hardening. They are 1018 steel.

    I guess I'm supposed to heat the parts, coat them with a carbaceous medium and them heat them past the "critical" temp or some such.

    So, what can I use for a carbaceous medium. I know you can buy special sauce but I'd have to order it and pay shipping and crap and I don't want to do that. Would pulverized charcoal or wood ashes suffice in a pinch?

    What about heat treating the 1018? Can I heat it up past the magnetic point and quench it in oil? I've done that with knife blades I've made out of saw blades and it worked pretty well. I don't know if 1018 can be hardened much by quenching, though.

  • #2
    Try a search of the site. This has been discussed many times.

    I seem to recall something about wrapping the part in hair, horse hooves, charcoal and/or more stuff then cooking it in your grill.

    I cant say how your hamburgers will taste afterward or how it will smell when it cooking though.

    Civil engineers build targets, Mechanical engineers build weapons.


    • #3
      Google Kasenite. It's available at welding supply houses.
      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      Thank you to our families of soldiers, many of whom have given so much more then the rest of us for the Freedom we enjoy.

      It is true, there is nothing free about freedom, don't be so quick to give it away.


      • #4
        Originally posted by Your Old Dog
        Google Kasenite. It's available at welding supply houses.
        Ditto on the Kasenite. It's the easiest way to go with small parts. Just make sure you have plenty of ventilation as it stinks to high heaven.


        • #5
          what are the parts and what do they need to do?

          there are a number of ways to case harden, the main variable being how deep the case is. There's a second variable, finish, which is where guy strive for those mottle blues and purples....I'm going to put colour case hardening aside.

          The question is how hard do you need the case to be....basically what determines the depth of the case is the soak time. For a model part, kasenit will create a case a few though deep. make sure the part is finished how you want it, the case is not deep enough for grinding afterward. heat the parts red then roll them around in the kasenit. repeat a couple times then heat red and water quench

          otoh if you want a really deep case on tooling that is going to be ground, you can send them out to a heat treater and hopefully get them thrown in with some commercial batch for not too much money. The can get a case up to around 50 thou.

          I've done both of these frequently. There is a middle ground where you pack everything in a steel box full of say bone meal or other carbon and keep it at temp for hours then quench. I haven't done this, i can imagine my city neighbors appreciation level for burnt bone meal, but it you don't want to buy something, this is where you're headed.

          What about heat treating the 1018? Can I heat it up past the magnetic point and quench it in oil? I've done that with knife blades I've made out of saw blades and it worked pretty well. I don't know if 1018 can be hardened much by quenching, though.
          won't do anything. Those saw blades should have enough carbon that they'd harden on a quench but not 1018. you can get a slight hardening of 1018 if you quench in a cold brine (the fastest quench), but i'm not sure how deep or how hard...also, the colder the quench the greater chance of cracking
          in Toronto Ontario - where are you?


          • #6
            I've used Kasenit in the kitchen, worked great. And, when I got home, my kitchen smelled fine.



            • #7
              In The Second Bedside Reader by Guy Lautard, p163, there is a story, "The Bullseye Mixture," that details the whole "pack case hardening" process. There is a bit of "witchcraft," after the manner of old-time platers and their recipes. But it is a good guide. Basically, pack case hardening is packing in finely divided, (powdered,) carbon, in the absence of oxygen, and cooking it at red heat for quite a while, (hours,) depending upon the size of the parts and the depth of the desired case. The witchcraft is the type of carbon and its source, (peach pits, bone meal, hoof trimmings, you name it.)
              Somebody will say it so it might as well be me.
              The fastest, easiest, best method is also potentially the most dangerous, and that is a bath of molten sodium cyanide. I have done it on a forge in a high school metal work class, under thew supervision of an instructor. None of us died.
              Sodium cyanide is difficult to find these days, but you put it in a small cast iron pot and heat it until the salt melts. This is at red heat and basically you have an amber liquid in a pot with a red bottom. At its melting point, there is very little vapor given off, but smart folks stay upwind. Hang the parts from lengths of iron wire and put them in the liquid. Obviously the parts have to be clean and dry. If you have to ask why, try another method. Length of time in the bath is experimental, and I have no suggestions other than experiment with some 4" nails.
              Duffy, Gatineau, Quebec


              • #8
                I'm going to throw this in simply because I've thought about it- but never tried it. Scrounge up some burnt exhaust valves and scrape the build-up that's on them into a container. Mash that up with a makeshift mortar and pestil, and there's your powder. Old spark plugs would also be a source, and maybe cracked heads, etc. At home I can find this type of residue in the furnace, and in the first stages of the flue. I feel confident that you can carbonitride with such a mixture.

                Probably best to just ask for a small qty of whatever a shop happens to have on hand. I used the simple process of heating a part red hot then grinding it into a container of the powder, repeat a few times, then clean it up, reheat and quench. An ordinary spike can be made so hard that a file will skip over it.
                I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-


                • #9
                  while im sure theres carbon inside engine blocks, I somewhat doubt on there being a usefuly extractable amount of carbon inside an engine block. Or inside any properly maintained natural gas furness.

                  A wood furness/fireplace should have a good supply..

                  but somehow I think an equivilent product is likey sold for about $5/lb, less then the hasel of harvesting it is worth.
                  Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.


                  • #10
                    I am not suggesting doing this although it may work just fine, more I am asking for an opinion than making a suggestion.

                    I worked with a guy years ago who case hardened parts with an Acetylene torch by repeatedly heating the parts cherry red then shutting off the Oxygen and allowing the yellow Acetylene flame to blacken the part with soot, which it did in a heavy layer. He would do this several times on each part, heat to cherry red then hold the Acetylene only flame until the part was somewhat cooled and covered with soot. This seemed to work, key word here being SEEMED, but since I never really checked to see how hard any of the parts got I really don't know. Anyone here do this or seen it done?