bearmtnmartin
bearmtnmartin SuperDork
12/7/17 11:39 a.m.

I have a friend who is a very talented machinist. Handy guy to know. He is in the process of building a vacuum oven for heat treating gears and whatnot. His stumbling block is not the actual construction of the thing, but rather the management of the process afterward. What gasses to use for how long and in what circumstance to achieve a certain result. I know nothing. I just learned in fact that this is a thing. But I told him I may know some peeps who may know some stuff......

RevRico
RevRico UltraDork
12/7/17 11:45 a.m.

Not sure if it's the same, but I did own a vacuum oven for a bit. 

No gases were involved with it though, it looked like an over grown toaster oven that you hooked a vacuum pump up to. 

I really don't know how to generalize it more than that, but I could maybe answer some questions if they come up. 

 

 it was this one. Maybe not the same kind he's thinking of building. 

bearmtnmartin
bearmtnmartin SuperDork
12/7/17 11:54 a.m.

Thank you for the suggestion. All I know is it heat treats in the absence of oxygen. 

stafford1500
stafford1500 HalfDork
12/7/17 12:52 p.m.

YOu could purge with Argon/Helium/Nitrogen/CO2 or whatever is the preffered non-reacting gas before you pull vacuum and that will give a no/low oxygen environment. Nitrogen, for some steels is bad as it can cause brittleness... it also is 78% of the air we breathe so there is a bit of mixed in with the oxygen.

Suprf1y
Suprf1y PowerDork
12/7/17 12:57 p.m.

Purge with Nitrogen, carburize with acetylene and quench with helium.

I worked on high vac heat treating equipment for quite ahwile, unfortunately I'm not a heat treater and don't have recipes.

bearmtnmartin
bearmtnmartin SuperDork
12/7/17 2:23 p.m.
Suprf1y said:

Purge with Nitrogen, carburize with acetylene and quench with helium.

I worked on high vac heat treating equipment for quite ahwile, unfortunately I'm not a heat treater and don't have recipes.

I believe it is the actual recipies that are the stumbling block, to avoid sending heat treated items to customers without any quality control.

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