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? on heat treating 1045

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  • #16
    Thanks - I think im going to practice on some scrap 1045

    iv done it before on 1045 just shooting from the hip and it turned out OK

    iv done quite a bit of O1 and that usually turned out ok also but not the last time i tried it for some reason did not take - also the pieces I did were very thin and warp happy

    I guess A2 is the stuff to use, very stable and no need to quench, it's like its specifically designed for it, never used it but kinda wish my gears were made from it instead of what I got...

    there's tons of these types of charts on line, im going to memorize the color I need and see what happens with some scrap...

    again is used motor oil a bad thing to use? water quenching just seems like it would build up a vapor barrier around the part,,, after reading what Wombat wrote I might try to rig something to the dewalt so I can spin the heated gears into the oil while quenching, before I always just used some kinda stiff wire and wiggled them around some...

    here's a heat chart; http://www.commonsenseevaluation.com...ture-Chart.gif

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    • #17
      This charts difficult - don't know about you guys but 1600f and 1700 look identical to 1900 and 2000, along with 1800 and 2100 looking identical

      http://www.productionmachining.com/c...tman-Table.jpg

      Going by the first chart (not this one)

      in Zahnrad's photo he should be somewhere between 1600 and 1700F maybe he will chime in and tell us what he had his furnace set at,,, my monitors on the default mode color wise, and yeah everybodys results will probably vary some...
      Last edited by A.K. Boomer; 11-04-2017, 11:12 AM.

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      • #18
        I have had good success with torch heat treating by getting the steel to a bright orange, then looking for brighter speckles to appear. Once that happens it is ready to quench. This seems to work on different alloys which have different heat specs. because the speckles don't appear until the right temp is reached.

        For quenching, I use real quenching oil. Most oils will burst into flames at these temperatures, so it becomes a little distracting to the quenching process when you are trying to keep the shop (and you) from burning down at the same time. On a gear, I would quench with a straight up and down motion to get the oil to flow between the teeth evenly. Spinning the gear will produce cavitation that will keep the oil from going between the teeth.
        Kansas City area

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        • #19
          Hi AK
          Spin quenching a shaft or hub in oil tank might be OK.
          But with a gear, the spin might tend to suck air -throw the quenchant out of the gaps between the teeth- right where it is needed.
          Maybe you could spin slowly with some other means to keep the quenchant turbulent.
          As we would expect, the crash quench - sudden falling of temperature to form martensite
          has to occur simultaneously all around the perimeter or else axial warping might occur.

          Fast quenching oils had a viscosity down around 50 SUS (Saybolt Universal Seconds)
          I am old but that unit was long gone before my time. Perhaps a vintage car expert could say what SAE number is close to that.
          Bottom line try a light grade, maybe like the old upper cylinder lubricant.

          These days water- polymer quenchants are used but I doubt that the additives are available in small quantities.

          There are probably lots of photos and even videos of gear hardening.
          Also I found this interesting paper where they tested carburized 8000 series steel gears to destruction.
          The paper covers a lot of the needs of the gear heat treat process.
          http://www.scielo.br/scielo.php?scri...82012000200005

          I don't know anything about carburizing except it is not suitable for 1045.
          However carburizing might be a better way to heat treat prototypes and small quantities of gears

          Take care not to burn your shop down!

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          • #20
            TG appreciate that - only time I ever had the oil ignite was when I went in too slow,,,

            still will look into finding some just for quenching as maybe there's unwanted carbon build up and stuff with regular oils -

            that could buffer the cool down process,,, as much as synthetics can take the extra heat im thinking the additives for multi-grades (polymers) would not be a good thing,

            Your right about the gears although when I was mentioning this I was mainly thinking of the larger internal gear, I could see if being a benefit to have it spinning as it would uniformly force the fluids into the teeth's depths and kinda act as an impeller...
            the sun and planets are much smaller and yeah would do like you said as they have bores that don't need to be hard and can just use all thread and anchor with washers and nuts and dunk up and down straight or maybe rapid oscillation...

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            • #21
              Originally posted by wombat2go View Post
              Maybe you could spin slowly with some other means to keep the quenchant turbulent.
              As we would expect, the crash quench - sudden falling of temperature to form martensite
              has to occur simultaneously all around the perimeter or else axial warping might occur.

              Fast quenching oils had a viscosity down around 50 SUS (Saybolt Universal Seconds)
              I am old but that unit was long gone before my time. Perhaps a vintage car expert could say what SAE number is close to that.
              Bottom line try a light grade, maybe like the old upper cylinder lubricant.

              These days water- polymer quenchants are used but I doubt that the additives are available in small quantities.
              Also thinking the temperature of the oil would be critical - anotherwords if you have allot of parts to do and your oil gets heated up a couple hundred degree's the latter parts will suffer this effect --- might be like starting with the heated piece a couple hundred degree's lower than what it should be,,, that's substantial...

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              • #22
                Originally posted by Erich View Post
                The carbon content determines how hard a steel can get.
                Yes and no. To a point. There's a knee in the curve, you see. Going much above 0.6% carbon won't give much more hardness. It can result in more carbides, though, which will help increase rubbing wear resistance.

                Originally posted by bob_s View Post
                Myself, I'd opt for quenching in salt brine cooled in the freezer
                They'll crack.

                To A.K.Boomer:

                1045 is what we call a "hypo-eutectoid plain carbon steel." For the "hillbilly hard" process, you can use a magnet. Transition temperature for hypo-eutectoid plain carbon steels is about 50F (28c) above the point where magnetic attraction is lost (Curie point). That difference is roughly about one visual color change.

                Quench in water if they're quarter or half inch thick or bigger. Use oil if they're thinner. NASA would have you use a purpose-formulated oil. Hillbillies know that fresh vegetable oil is good enough for hillbillies. Peanut oil is a good choice. A lot of hillbillies have adequate success with transmission fluid (new, not used).

                Warping is caused by either uneven cooling or uneven residual stresses in the part. You can minimize residual stresses by "normalizing." Heat the item above the transition temperature and let it cool slowly in still air. Repeat two or three times.

                You're on your own to prevent the uneven cooling.

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                • #23
                  Originally posted by A.K. Boomer View Post
                  Also thinking the temperature of the oil would be critical - anotherwords if you have allot of parts to do and your oil gets heated up a couple hundred degree's the latter parts will suffer this effect --- might be like starting with the heated piece a couple hundred degree's lower than what it should be,,, that's substantial...
                  Production units have a heat exchanger to take the heat frm the quenchant to a cooling tower.
                  The HX has a throttling valve, and also the quenchant is heated so that the temperature stays in optimum
                  range from first shift in winter to the hottest day in summer.

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                  • #24
                    Nice thanks Lee I will practice with the magnet trick, thanks for understanding the specific needs of a hillbilly to keep things as simple as possible lol

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                    • #25
                      Originally posted by A.K. Boomer View Post
                      Nice thanks Lee I will practice with the magnet trick, thanks for understanding the specific needs of a hillbilly to keep things as simple as possible lol
                      The curie temperature& magnet trick should be pretty good "calibration point" for visual reference. (Note that alloying has big effect on curie temp)
                      https://books.google.fi/books?id=Ea8...rature&f=false

                      1060 steel has curie temp of 732c
                      Location: Helsinki, Finland, Europe

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                      • #26
                        Originally posted by MattiJ View Post
                        The curie temperature& magnet trick should be pretty good "calibration point" for visual reference. (Note that alloying has big effect on curie temp)
                        Indeed! Alloying will push the critical temp around as well.

                        The change to the Curie temperature is NOT necessarily the same at the change to the critical temperature. This is why the magnet trick should ONLY be recommended for hypo-eutectic plain carbon and hypo-eutectic low-alloy steels. (It will work for a few steels outside of this limitation, but one must do one's homework to find them.)

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                        • #27
                          Originally posted by Lee Cordochorea View Post
                          Indeed! Alloying will push the critical temp around as well.

                          The change to the Curie temperature is NOT necessarily the same at the change to the critical temperature. This is why the magnet trick should ONLY be recommended for hypo-eutectic plain carbon and hypo-eutectic low-alloy steels. (It will work for a few steels outside of this limitation, but one must do one's homework to find them.)
                          Based on couple of sources the curie temp is pretty much same as critical temperature (A3) for low alloy steels between 0.45 and 0.8% carbon content. Above 0.8 points of carbon the curie temperature is equal to A1 or beginning of austenite formation temperature.
                          Location: Helsinki, Finland, Europe

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                          • #28
                            Ok last question, on the large internal gear, it's about .400" thick and about .550" difference (radius wise) from the ID to the OD

                            OD is about 4.300 and Id is about 3.200"

                            I am planning on using the outer part of the gear for a bearing surface and also gear will need to be drastically modified on one side and taken down some on the OD,,,

                            question is - is do i heat treat it before or after? im sure it will be more squirm happy in it's thinner state after machining so maybe heat treat it before ? let it go through its phase and then machine it as it will be no match for carbide, BUT, will it be hard enough in the area's inside? that's the places im planning on running roller bearings on,,,

                            guy at the heat treat place said it will be hardened through and through but I would think the shock of cooling would get the the outer structure far better,

                            I also don't have a problem with machining close to size and then heat treating it, then final machining it --- might be the way to go to ensure hardness and correct any warpage deviations (except the gears teeth im on my own with that one I know - so maybe keep it stable for heat treating in it's larger form due to that, if it gets hard through and through)

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