metal hardening help

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I built a tubing roller and just made some roller dies for square tube. I put knurles in the dies and need to harden the material. I was wondering if heating them up in the forge and dipping them in oil is the right way to go or do you guys have some other ideas. thanks a lot. kris
Reply:If the dies are made from mild steel, it doesn't have a high enough carbon content to be heat treated. Do you want the knurling hardened so it won't deform? If so, you could case harden the surface of the dies using various mixtures/types of carbon, but buying a can of Kasenit would be easier. Here's a bit of info I found about it in a quick search: http://bbs.homeshopmachinist.net/showthread.php?t=28079The material is available from places like MSC, McMaster-Carr, maybe ENCO, etc. Some good hardware stores even carry it.One of these days, I'd like to make it from scratch; from Potassium carbonate, iron fillings, and nitrogenous animal waste like hoof and horn scraps. Deep hardening is more difficult.
Reply:Originally Posted by Oldiron2If the dies are made from mild steel, it doesn't have a high enough carbon content to be heat treated.
Reply:They have been turned into Martensite or Bainite I imagine. Once steel is heated beyond about 1600 degrees F., it temporarily changes into austenite. How fast it cools down, determines which form of steel crystalline structure forms. Martensite being the most brittle, that would be what I guess it has turned into. The exact alloy of iron and carbon has a great deal to do with the grain structure that can form. Then there are so many other alloying elements that create an immense number of possibilities. Just keep a good supply of Vise Grips on hand!! City of L.A. Structural; Manual & Semi-Automatic;"Surely there is a mine for silver, and a place where gold is refined. Iron is taken from the earth, and copper is smelted from ore."Job 28:1,2Lincoln, Miller, Victor & ISV BibleDanny
Reply:As I am learning more about case harding it did make me wonder a little bit. These clamps are for thermoplastic materials which are usually fiberglass or carbon fiber and a plastic heated to melt then pressed to shape. The clamps are in contact with all these materials and often it's burning. Could this possibly act as a case harding??