HT multiple SS knives at the same time?

L

LCoop

Joined
May 5, 2007
Messages
629
Ok I've been a long time reader here and have gotten alot of knowledge here, just dont' post much. I recently began making 440C knives that I heat treat myself in my homemade electric oven. Maybe I've missed it mentioned and I've searched but I have a question on HTing multiple blades on the same oven firing.

Presently I put 3 foil wrapped blades in my oven and bring it up to temp which takes about 30 minutes then when it reachs my set value of 1875 I let them soak for 15 minutes. I then open the door take one out, close the door quickly and plate quench that blade. So on and so on.

Since 440C is a air cooled steal would I just be ahead to bring them all out at the same time and then plate quench each as soon as possible?

I'd appreciate any advice or opinions. Thanks
 
You might do three or four together in a foil envelope [edge to spine , edge to spine ] then plate quench .Of course you have to have a big enough plate.
 
If your plates are big enough, you could just do all three envelopes at once. One of the big advantages of plate quenching is that the hot blade never sees oxygen. All that opening and closing the door will cause expansion / contaction of gas and the envelope will breathe.

What you are doing and what you are proposing will both work, but you may be losing some of the benefits possible by plate quenching.

Rob!
 
Well I thought I'd been careful to give a detailed explaination of the way I do it but I goofed. Sorry. I should have said I place 3 SEPARATELY foil wrapped blades in my oven now. I take one out at a time remove from the foil and plate quench. I have plenty of 1" thick alum quenching plates to do each knife separately, so are you saying I should plate quench while still in the foil wrap? Seems I remember reading to cut and slide the blade out to plate quench. I'll tell ya up front I fight the heck out of "sliding" them out, they are not sticking to the foil but they sure don't slide out either. If I can plate quench in the foil that would be a lot easier! Just curious how you experts do it. Thanks for helping answer these questions.
 
Yes you can quench in the foil,I use 12 X 12 X1-1/2" alum plates and do as many as 5 at a time,pull them all at the same time,put them on the plate and cover with the top plate,let sit about 2 minuets and done.
Stan
 
If all your blades are the same thickness, you can put many of them in the same packet, and then you only have to deal with one packet. You do have to be careful not to let them shift around in the packet.

Definitely quench in the packet, and, if it were me, I'd soak 440C for 25 minutes at temp.

You can powder the blades with talcum powder before you wrap them, it will keep them from sticking to the foil
 
LCoop said:
so are you saying I should plate quench while still in the foil wrap? .
Click to expand...

Yes, definitely. You're going to love the results. ....and while 15 minutes will pretty much get the job done, I agree with RJ Martin that longer is better.

I tried putting multiple bades in a packet and did not like it. Too easy to get them overlapping and they don't make even contact with the plates - or worse, could get warped. Apparently it works for some though....

Rob!
 
Well thanks for all the advice! This kinda brings me to my next question. Presently I put my blades in the oven and then start the oven. Like I said it's a homemade electric oven but it still comes up to 1875 in about 28 minutes. Once it reaches temp I start timing for my 15 minute soak. So I'm pretty sure they are up to temp but do you all think I should still go to a soak of 25 minutes?

Then I believe I've read that some folks bring their oven up to temp and then put the blades in. So what time should a fella shoot for if he's putting in a room temp knife in for a soak? Because eventually I'd like to HT more than my present 3 blades every time I fire the oven for economical reasons.

Once again I'd like to thank everyone for their help on this. I've bookmarked several "knife" forums but this seems to be the only one I check everyday to learn from and trust. Thanks
 
What I do for 440-C is ramp to 1250 hold for 15 min,ramp to 1650 and hold for 15 min,ramp to 1875 and hold for 35 min. then plate quench,
I do this for all complex Stainless as I understand it takes the 35 minuet soak to get all the alloying components into solution.
Stan
 
You're going to get different answers on this - most of which work just fine. For my part, I put blades in the cold oven and start the cycle. I don't believe any equalizing stops are necessary with a thin section like a knife blade. Depending on the steel, all stainless gets 30 to 60 minutes soak once they have reached full target temperature.

Mine also get cryo - at least two hours and usually overnight.

Not knocking anyone else's process. Just describing ours. You'll find something that you are comfortable with too.

Rob!
 
You must log in or register to reply here.
Back
Top