Announcement

Collapse
No announcement yet.

Looking for ways of hardening small parts without decarburizing the outside

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Looking for ways of hardening small parts without decarburizing the outside

    Yes, I know about stainless steel wrap and piece of paper. Don't have any SS wrap here, need to get these parts done for a guy I know, he brought them to me because I can do them rapidly. But I did not know about some of them needing to be hardened until I had them ready (nice surprise!).

    Parts are small cylinders, about 10 x 15mm, and they are knurled. I need the knurling to be hardened with the rest of the part, and obviously they cannot be knurled after hardening. Parts are made of W1.

    They do not need to be glass hard, but do need a resistance to deforming, and they need wear resistance. The material is what it is, it is supplied material, or I would think immediately of using A2.

    I do not have the oven up and running yet, so these will be torch hardened.

    So, I have "heard of" various "home remedies" for the hardening vs decarb problem. Some suggest coating them with soap (?). Some suggest heating somewhat and then dipping in sugar before heating the rest of the way. Some suggest dipping in thick oil first. Some say to use the "reducing portion" of the flame, others, and I agree, say that part is not as hot, although it might be "hot enough".

    I could heat them inside a capped piece of pipe, but I'd not know if they were hot, and I doubt getting the pipe open before the parts are too cold to harden.

    Any word on what actually works?
    CNC machines only go through the motions

  • #2
    I don't think you're going to have much problem with decarb on W-1. That is more of a problem on higher alloys. A mixture of baking soda with borax and alcohol makes a good protectant, it melts into a glassy substance (to protect the surface)and the carbonate keeps the carbon levels stable. This trick was favored by old-time blacksmiths according to the literature I have.
    25 miles north of Buffalo NY, USA

    Comment


    • #3
      I definitely have had issues with a soft decarb surface when hardening W1 before. I want the points of the knurling to be hard.
      CNC machines only go through the motions

      Comment


      • #4
        Small part from W1 needs so short heating time that unless you seriously over-cook them I’d expect to get file-hard result all the way to surface.
        Location: Helsinki, Finland, Europe

        Comment


        • #5
          Brownells sells products similar to what Nickel CIty Fab describes. Gunsmiths have forever had the need to harden small parts and have found the most practical easy ways of doing so. Their requirements pretty much mirror yours.

          Here is just one https://www.brownells.com/gunsmith-t...-prod1122.aspx

          Comment


          • #6
            Originally posted by J Tiers View Post
            I definitely have had issues with a soft decarb surface when hardening W1 before. I want the points of the knurling to be hard.
            I guess it's possible, but I haven't had many issues. On the other hand, my work piece sizes were a bit larger. In any case, please consider the recipie I mentioned. In keeping with what MattiJ says, I was heating mine to orange heat within seconds with a large rosebud torch.
            25 miles north of Buffalo NY, USA

            Comment


            • #7
              consider heating them in coal, in the reducing zone.

              Comment


              • #8
                Well I did the "sugar hardening", and that seemed to work OK. There was a coating of carbon on the parts, and they seem to be hard on all surfaces. Heated up, dragged through some sugar in a small can, then when they seemed to be well coated, heated the rest of the way to temperature and quenched in water.

                The "sugar hardening" seems to be a way of putting a "case" on the parts if you have low carbon steel, so if anything, it may have added some carbon to the surface. A file did skid off them, and while they do not need to be glass-hard, it does no harm either, as they do not have particular stress. They get loctited onto a shaft, the knurling is for traction.
                CNC machines only go through the motions

                Comment


                • #9
                  JTiers, that is absolutely brilliant. I just learned something. 2 seconds thought shows that it works because the sugar is a hydrocarbon, and melts into a protective glaze.
                  25 miles north of Buffalo NY, USA

                  Comment


                  • #10
                    Not my idea, I forget where I first heard of it. It was being suggested as a way of developing a case, alternate to "Kasenite".
                    CNC machines only go through the motions

                    Comment


                    • #11
                      Sweet!
                      Location: North Central Texas

                      Comment


                      • #12
                        Originally posted by MattiJ View Post
                        Small part from W1 needs so short heating time that unless you seriously over-cook them I’d expect to get file-hard result all the way to surface.
                        For small cutters which I've made I found that to be the case. Same with O-1. The only downside to not using some manner of protectant is the black oxide coating. And it takes some sanding or at least a brisk wire brushing to remove it. Sanding would, of course, remove some of the sharpness of the knurling. And the times I've wire brushed it the color ends up spotty.

                        Mostly for the avoiding of this coloration issue I thin I'd opt for trying that coating of the borax, baking soda and alky. Or I don't see why water would not work as well. Perhaps using the coating along with a wire wrap or metal screen wrap to hold the coating much like Clickspring does with his parts?
                        Chilliwack BC, Canada

                        Comment


                        • #13
                          I had not read about the sugar idea before either. Was it hard to remove the carbonized sugar?
                          Chilliwack BC, Canada

                          Comment


                          • #14
                            No, most of it came off in the quench.
                            CNC machines only go through the motions

                            Comment


                            • #15
                              Originally posted by J Tiers View Post
                              No, most of it came off in the quench.
                              Thanks, it's on the list to try for next time.
                              Chilliwack BC, Canada

                              Comment

                              Working...
                              X