What am I missing?

D

David66

Well-Known Member
My heat treat oven is due this week so I am getting myself ready for the big event.

In many posted shop pics there is a toaster oven or in many HT threads a reference is made to a toaster oven or the kitchen oven. Why can't the HT oven be used for tempering?

All help is greatly appreciated.
 
It CAN, but the difficulty comes in when your using the HT oven to hardening...and then try to use the same oven for tempering.... it MUST cool down to a temp low enough to temper. Ideally you want to temper as soon as possible after hardening to avoid stress cracks in a blade. In most cases a HT treat oven takes several hours/overnight to cool down once you've used it for hardening.

Another problem that often occurs when using a HT oven on carbon/allow steels that require oil quenching is that that there is a great deal of scale formed during the heating operation in a HT oven (generally these types of steels are not foil wrapped because you simply cannot get them out of the foil and into the oil in time to get full hardening).
 
I will not recommend to do as I do, but I have a 22.5 Evenheat oven, 220V. It must have around 2, to 2 1/2 hours to cool down to below 250F with the door open, which is not good for the elements, but I do it anyway. I crack it open for maybe 30 minutes, then open it wide open. After it drops that low in temp, I re-program for the first temper and re-start it. It will go as much as 25° over temp, but then back off and settle in. Then I put the blades in. As far as carbon blades go, I use that AST, or ATP, or whatever it is that you paint on. Works great for me. No appreciable de-carb, and it comes off in the quench, which I'm sure I'll have to filter out one day. I use a lot of 01, and have never had it crack in quench, or while the oven cooled down, but as I said, I will not recommend what I do. You will have to decide that for yourself. The way I see it, is, if I have to buy elements every 4 or 5 years, so be it. This oven has been going over 3 years now with no problems. If you are going to use a high carbon 10XX steel, or similar, you could give it a snap temper in your kitchen range while the oven cools.
 
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Thanks

I am using O1 for right now. I am comfortable with the process; I was not aware that an oven takes that long to cool. I guess it is just another excuse to buy something (every shop needs a toaster), or give my wife more counter space.:rolleyes:
 
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