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View Full Version : Didnt get my 60 rockwell.



Tod Lowe
01-21-2011, 05:47 AM
Hey guys.
I heat treated some ats-34 at 1930 for 30 minutes then tempered at 275 for two hrs. My rockwell ended up at 57 hrc. I think my aluminum quench plates were not big enough to do all 4 big blades at the same time.
My question is: Would a dry ice treatment raise the rockwell after I already tempered or should I just go back and reheat treat from the start?
Im Open to all tips and suggestions also...as long as its constructive! :biggrin:

Sampson knifeworks
01-21-2011, 09:59 AM
Hi, It sounds like they did not cool fast enough. I usually do one at a time in the plates and let the heat in the kiln recover before doing the next one. I always have better results with an oil quench, like the manufactors suggest. My plates are 2"X6"X12". I would also start over from scratch instead of freezing too, but that's just my opinion, hope it helps.
Sincerely,
Sampson Knifeworks

Tod Lowe
01-21-2011, 10:51 AM
Thanks Sampson.
What quench oil are you using for ATS -34?
Are you SS foil wrapping the blades when using the oil as a quenchent?
These blades are 3/16 so im sure I didnt get it cool fast enough. I usually get a 59 or 60 after tempering.
Im leaning on just re heattreating them this weekend as you suggested.

Silverman
01-21-2011, 11:07 AM
Tod, I use ss foil for RWL-34 and i heat treated at 1980 for 15 minutes and quench in compressor oil (compAir fluid force or gardner denver aeon 3000) after quenching before tempering hardnes is 68-70HRC and tempering at 345F hardness is 64.5 HRC. Tempering at 400F hardness is 61-62HRC. I hope that will help you.

John Barker
01-21-2011, 11:32 AM
ATS-34 should be easy to air quench. I would do try it again and quench them individually with your plates. Cryo may only get you 1 point higher.
-John

Tod Lowe
01-21-2011, 11:56 AM
Thanks John! I usually dont have a problem....just got greedy and tried to get them all at once.
Why is the oil quench frowned upon by so many. Is it just the mess?

Tod Lowe
01-22-2011, 05:13 AM
Thanks Silverman.....I totally missed your reply yesterday.
So I guess you just oil quench the blades with the foil on them like with the plates?

Silverman
01-22-2011, 07:44 AM
Yes. Oil quenching with low viscosity oils will give much higher hardness. SS foil will slow the cooling and you will not experience twisting and warping. Its important first to cool ticker part of the knife and after that the thin.

John Barker
01-22-2011, 08:04 AM
Todd,
I don't think it's frowned upon, but I don't see the point. Oil can be messy and it can catch fire. I for one don't want to be taking foil off a glowing orange blade. By the time you take the foil off it will have already started cooling significantly. You can plate quench it in a much shorter time. I also temper ATS-34 at 500F for 2 hours twice. Good luck.
-John

Silverman
01-22-2011, 08:10 AM
I am quenching the blade in oil without removing the foil. There is no problem with fire ignition if you keep your blade sunk in oil.

Sampson knifeworks
01-22-2011, 08:50 AM
Thanks Sampson.
What quench oil are you using for ATS -34?
Are you SS foil wrapping the blades when using the oil as a quenchent?
These blades are 3/16 so im sure I didnt get it cool fast enough. I usually get a 59 or 60 after tempering.
Im leaning on just re heattreating them this weekend as you suggested.

Hi Tod,
To answer your question, I use brownell's tough quench, but It's tricky if your using foil, if your removing the foil before the quench it has to be very fast and no fumbling. Leaving the foil on sounds like it's worth more experimenting for me. It would be great if they made a dip coating that worked well at those temps, I have tried turco & that atp stuff brownells sells without any luck, too much scale! I believe doing the plate thing one at a time will be worth the next try, please let us know the results. my suggestions seem to work for me, but we are all still learning and trying to find what works best. Good luck with the new heat,
Clint

Tod Lowe
01-22-2011, 12:16 PM
Right on Clint. More then one way to skin a cat.
I probably will plate quench again this go around. I was curious about the oil procedure because I never hear anyone talk about it.
I appreciate the tips and info man.
Thanks