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  • case hardening

    Can free machining steels like 12L14 be case hardened properly or does the chemical makeup that makes it free machining cause problems.
    The shortest distance between two points is a circle of infinite diameter.

    Bluewater Model Engineering Society at https://sites.google.com/site/bluewatermes/

    Southwestern Ontario. Canada

  • #2
    They can be case hardened, the free machining content does not present a problem. 12L14 is a low carbon steel, similar in carbon content to hot and cold rolled steels. Higher carbon content steels such as 11L41 are direct hardening and case hardening can cause thin sections to become brittle.
    Jim H.

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    • #3
      There's so many processes available today like Ion Nitrite ....
      ... it's worth a study but a few minutes with your heat treater might be better.

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      • #4
        While there may well be many heat treating options available, the home shop machinist usually does not have the luxury of being able to utilize them, let alone have a heat treater. Most HSM heat treating is done on a single part, sometimes no bigger than your little finger. That is where the use of heat treating compounds such as Kasenit or tool steels such as O1, A1 or W1 come into play.

        My heat treat equipment consists of a propane or Prestolite torch depending on part size, a magnet, a can of water or oil and a toaster oven for drawing. I suspect this is typical of most home shops.
        Jim H.

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        • #5
          Heat-treating in a home-shop is a good thing.
          I'm not attempting to be "dissuasise".

          Heat-treating is like welding, in that a 10 minute one-on-one face to face with a professional,
          is worth semester of education via, the interwebs.

          Most heat-treaters give freely of knowledge, because it may gain word-of-mouth customers.
          Most of what they offer just aint gonna get done at home.

          PS;
          8620 is about as free-machining as it gets, used for the right applications it's T!ts.
          Threads need consideration and a few other details.
          You'll get your part back with wooly sandy packing in threaded holes.

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          • #6
            Wondering if heat treating or case hardening a lead containing steel is a good idea?

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            • #7
              Leaded steels are routinely heat treated and case hardened following the same procedures as their standard counterparts.
              Jim H.

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              • #8
                I routinely have 12L14 case hardened by a heat treating company.

                One part is a long adjusting nut with deep 10-32 threads one end and a hex socket on the other end. We had the heat treater initially do a run of samples with varying depths of case. Tested the hex by torqueing it to determine the best depth of case, too little didn't add enough strength, too much made the thin wall too brittle. .008" depth is best for this part.

                The parts come back clean with no scaling at all, bright and shiny since they're done in an inert atmosphere. We did find the parts needed to be very clean, almost sterile, any trace of cutting fluid in the threaded holes left a residue which wasn't good. Otherwise the threads came out good.

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                • #9
                  Most heat treating goes wrong during the tempering phase, no pun intended, looking at colours is ok but not the best as it is difficult, the lead tin bath method seems to work better, just my opinion
                  Just pick your temp
                  http://www.weights-and-measures.com/xcommetalsalt.html
                  Least its what the knife folk tell me!
                  Mark
                  Last edited by boslab; 08-14-2014, 11:17 AM.

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                  • #10
                    I should have mentioned that this case hardening will be done in a home shop, I have case hardening compound. The parts need to have a good finish (milled then polished), better then you would get with low carbon steel which is why I am thinking free cutting. The case only has to make the part surfaces a bit tough and does not have to stand up to repeated wear and tear.
                    The shortest distance between two points is a circle of infinite diameter.

                    Bluewater Model Engineering Society at https://sites.google.com/site/bluewatermes/

                    Southwestern Ontario. Canada

                    Comment


                    • #11
                      Originally posted by loose nut View Post
                      I should have mentioned that this case hardening will be done in a home shop, I have case hardening compound. The parts need to have a good finish (milled then polished), better then you would get with low carbon steel which is why I am thinking free cutting. The case only has to make the part surfaces a bit tough and does not have to stand up to repeated wear and tear.
                      Sometimes if you have a friendly local heat treater they will throw your part in with a bigger batch of case hardening to save you the minimum charge. A professionally done part will come out looking as good as it went in. That's not usually the case with doing it at home.

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                      • #12
                        No that's not going to happen.

                        Is there a plate equivalent to free machining steel or is it just round stock???
                        The shortest distance between two points is a circle of infinite diameter.

                        Bluewater Model Engineering Society at https://sites.google.com/site/bluewatermes/

                        Southwestern Ontario. Canada

                        Comment


                        • #13
                          Originally posted by loose nut View Post

                          Is there a plate equivalent to free machining steel or is it just round stock???
                          Freemax 15
                          http://www.google.com/url?sa=t&rct=j...E0oJOttVtFe1-g
                          =========================
                          Freemax 15 is a low carbon, free machining steel plate. These plates were developed for enhanced machinability to reduce machining time and increase productivity while also reducing wear and breakage of machining tools. Freemax contains higher levels of sulfur which makes it not only free machining but also improves surface finish characteristics. It contains carbon levels comparable to other low carbon grades such as 1018 so it will respond to similar hardening methods such as carburizing. These plates are ground top and bottom to a decarb free, oversize finish and sawcut on the widths and lengths.

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