Heat treating small stainless (slipjoint) parts

[Hubert S.]

I have been wondering about how best to wrap small parts, e.g., the spring for a slipjoint, in foil for heat treating. Do you wrap each part separately in its own small pouch or do you combine parts (maybe blade + spring)?

 

[Signalprick]

I put a set of parts (blade + spring) into one pouch. Sometimes I do 3 parts per pouch. Just depends on the size of the batch I'm heat treating.

 

[Hubert S.]

I put a set of parts (blade + spring) into one pouch. Sometimes I do 3 parts per pouch. Just depends on the size of the batch I'm heat treating.

Thank you. Just to make sure, you put them next to each other so that one part ends up above the other in the furnace, or are they end to end, or side by side?

 

[Ken H>]

I tend to HT the blade and backspring in the same SS wrap with the backspring nested around the blade so it's one layer. When clamping in quench plates they act as a single unit. Of course they have to be tempered separately as the backspring tends to require tempering up around 1100°F to lower Rc to mid 40's

 

[Hubert S.]

I tend to HT the blade and backspring in the same SS wrap with the backspring nested around the blade so it's one layer. When clamping in quench plates they act as a single unit. Of course they have to be tempered separately as the backspring tends to require tempering up around 1100°F to lower Rc to mid 40's

Thank you. I was a bit concerned that the parts may shift and end up overlapping when they go in the quench plates, but that does not seem to be an issue.

I do not have a tempering oven that goes to 1,100°F, so I am planning to temper spring and blade together, and then temper the spring again the next day after the main oven has cooled.

 

[Ken H>]

I have found pressing the SS foil tight around the blade/backspring will hold them into place just fine. First temper together will work just fine. I also use my HT oven for tempering the backspring. Actually by the time the first temper in the tempering oven (PID controlled toaster oven for me) the HT oven can be cooled enough to the final temper.

 

[Hubert S.]

I have found pressing the SS foil tight around the blade/backspring will hold them into place just fine. First temper together will work just fine. I also use my HT oven for tempering the backspring. Actually by the time the first temper in the tempering oven (PID controlled toaster oven for me) the HT oven can be cooled enough to the final temper.

Ken, how much of a gap do you leave between the parts?

I use a PID controlled toaster oven for tempering as well. After two temper cycles, the main furnace might be cooled down enough, but I am normally ready to just turn off the oven and do something else...

 

[Signalprick]

The parts should all be flat in the envelope. They go into the envelope like this. It's OK if one is on top of the other vertically. They can touch. You might be overthinking it a little.

 

[Signalprick]

I throw the blades in the kitchen oven and the springs back into the Paragon for obvious reasons. That way when the cook is done, it's done.

 

[Ken H>]

The parts should all be flat in the envelope. They go into the envelope like this. It's OK if one is on top of the other vertically. They can touch. You might be overthinking it a little.

That's exactly what I'm referring to as "nested". Blade touching backspring is no problem, or if there's a small space no problem either. Just what fits easy.

Two cycles in the tempering oven won't hurt anything, but No reason to temper backspring twice. It's going to get tempered again in the HT oven anyway.

 

[Hubert S.]

Thank you, Jason and Ken. I have had some pouches swelling/inflating a little bit in the oven, that's why I was wondering if the separate parts would stay in place. I am probably overthinking it.

 

[Ken H>]

As long as the SS pouch is folded tight around the edges close to the blade 'n backspring even with some ballooning the parts should stay in place. Good luck and have fun.

 

[Hubert S.]

Thanks, I will give it a try after the Holidays.