Knife makers

[Puggy625]

For those that use a Paragon oven for heat treat, what program settings are you using to heat treat ats-34? Ramp rate is what I'm most interested in.

[MikeConner]

Regardless of the brand oven used most of us ramp the temp as fast as possible 9999 for everything.

[Jason Fry]

Agree with Mike. Ramp rate isn't critical, IMO. I typically start cold and stage mine at 1500-1600 for a few minutes to equalize, then on up to 1950 for CM154/Ats-34. Plate quench, then dry ice/kerosene immediately. Temper after that, typically from 450 to 550, depending on the hardness test results. I have found some inconsistency between bars or batches, so that I can't just say "temper at *** for RC 59."

[Puggy625]

Ok on the ramp rate, just wanted to make sure I didn't ramp too fast and warp or crack anything.

Is the cryo absolutely necessary? I've read different things and most say no, some say yes.

[MikeConner]

I don't think it's absolutely necessary but it certainly doesn't hurt. Most gain I've seen is a 1 point difference. A lot of guys are using dry ice and RV antifreeze these days to eliminate the toxic fumes and fire danger associated with kerosene or acetone.

[Bjankowski]

I don't think it's absolutely necessary but it certainly doesn't hurt. Most gain I've seen is a 1 point difference. A lot of guys are using dry ice and RV antifreeze these days to eliminate the toxic fumes and fire danger associated with kerosene or acetone.

I agree 100% will all Mike said; the RV antifreeze is sure safer!

[Puggy625]

OK, my first test piece came out really low. Here's my recipe, so please tell me what I need to change to get the hardness up. It came out at about 51, way too low. 1/8" ATS-34

Start cold oven and ramp full to 1450, hold for 10 minutes.
Ramp full to 1950, soak for 15 minutes (I think this is where I messed up. Should be about 45 minutes)
Remove and plate quench to below 125.
Immediately, place in oven and soak at 450 for 2 hours.
Shut off oven and let it cool to room temp.
Start oven and soak at 450 for another 2 hours.

Open to suggestions about what to modify to get 59-60, at 51 now.

[1shot]

following

[MikeConner]

From my experience that should have resulted in about 63-64 after plate quench and around 59-60 after temper. Are you sure of the steel type and how did you test for hardness.

[Jason Fry]

Agree with Mike, didn't see anything wonky in your procedure. Did you foil wrap them?

[Puggy625]

I agree from the research that I've done, it should have came in at least closer to 59-60 than it did. Now, the testing was done with a portable "rebound tester" that a friend (mechanical engineer) borrowed from his office. I'm not 100% confident in the test as the rebound testers specs say it isn't suitable for thin parts like knife blades, but he insists that it is accurate within 0.5 harness. I don't have access to any files or any other hardness tester. I know for sure the test piece was ATS-34 (at least that what I ordered and it was marked when I received it). It was foil wrapped during the high heat cycle and plate quench. I would like to get it tested by a more accurate tester, but lack of access is preventing that at the moment.

[Jason Fry]

You could mail it to me and I could test it for you, if you want. I have a regular bench model tester. PM me if you're interested.

[Puggy625]

OK, thanks. I'll let you know pretty quick.

[Jason Fry]

What does it do when you hit it with a regular file? 59 will dig a little, not totally skate, but 51 will dig quite a bit.

[Puggy625]

I hit it a few times with a file and it skated without digging in. It definitely had the "glass" sound that is usually associated with a hard metal piece. I will recheck it again tonight when I get home.