M.B. Naegle
Diamond
- Joined
- Feb 7, 2011
- Location
- Conroe, TX USA
So we had bought a second oven a few years back, and we opted for one with the plumbing for a controlled atmosphere. Initially we thought about using Compressed C02 to carborize parts, but then we realized that the risk of asphyxiation wasn't worth it so we stuck with our usual procedures of treating O1, A2, D2 steels and using stainless bags to seal them.
We're currently trying to improve the process for a D2 part that looks like a long skinny blade. It's not sharp but rather acts as a precise guide for another sliding part. These pieces tend to bow when treated, so we're looking for a way to make them that's less involved than the typical rough cut, stress relief, finish cut, stress relief, heat treat, grind, etc. until it's mostly within flatness tolerances.
We've tried bolting a pair together, and bolting them to a "tombstone" fixture, with varied success, but one idea one of our guys had was to hang them vertically off a little rack. To do so we couldn't wrap them, so we're revisiting the atmosphere feature on the oven.
Currently it is plumbed to Argon and is getting 5 lbs. positive pressure. I heat treated a drop of D2 last night and started running the Argon with a closed door as soon as I started a heat treating cycle, thinking the air would be forced out. The oven is 13"x13"x36". Went through a cycle and the piece scaled badly. I'm thinking that the air was trapped in there, so how is the oxygen supposed to escape and be replaced by Argon? There is only one inlet into the oven for the gas, but no outlets, so I'm thinking the door is the only escape? Argon is heavier than air too, so should I leave the door cracked on top?
I'm confident with our heat treating procedures, but throwing in the atmosphere component is confusing things. Anyone have any tips or advise on the subject?
I'll add too that IMO there's no way around the bowing issue with these parts other than lots of stress relief in between operations, but It would be nice to see the atmosphere feature put to use.
We're currently trying to improve the process for a D2 part that looks like a long skinny blade. It's not sharp but rather acts as a precise guide for another sliding part. These pieces tend to bow when treated, so we're looking for a way to make them that's less involved than the typical rough cut, stress relief, finish cut, stress relief, heat treat, grind, etc. until it's mostly within flatness tolerances.
We've tried bolting a pair together, and bolting them to a "tombstone" fixture, with varied success, but one idea one of our guys had was to hang them vertically off a little rack. To do so we couldn't wrap them, so we're revisiting the atmosphere feature on the oven.
Currently it is plumbed to Argon and is getting 5 lbs. positive pressure. I heat treated a drop of D2 last night and started running the Argon with a closed door as soon as I started a heat treating cycle, thinking the air would be forced out. The oven is 13"x13"x36". Went through a cycle and the piece scaled badly. I'm thinking that the air was trapped in there, so how is the oxygen supposed to escape and be replaced by Argon? There is only one inlet into the oven for the gas, but no outlets, so I'm thinking the door is the only escape? Argon is heavier than air too, so should I leave the door cracked on top?
I'm confident with our heat treating procedures, but throwing in the atmosphere component is confusing things. Anyone have any tips or advise on the subject?
I'll add too that IMO there's no way around the bowing issue with these parts other than lots of stress relief in between operations, but It would be nice to see the atmosphere feature put to use.