5160, O1 heat treat - questions

B

billf

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Oct 9, 2003
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I'm hoping Mete or anybody else can help me out with a few questions - Yes I did try to search, but it won't work for me (reg or advanced, all forums or just this one)

Anyway, I've previously used mostly 1095, heated in forge to loss of transformation shadows, then quenched in Park #50 oil, tempered in toaster oven - good results

I'm trying some O1 and 5160 now, forged then normalized x 3 with gradual decrease temp, then ground. I now have an Evenheat oven, as I'm looking for a little more HT consistency, so my questions are the following

1. I think Park 50 is too fast for O1 and 5160, trying to get Park AAA but can't find any in small quantity (IE 5 gallon). What is a good substitute for AAA or a source for small amnts?

2. Thinking about 1475 with a 5 minute soak for O1(3/16 blade) and perhaps 1525 5-10 minute soak for 5160 ( 1/4 blade, sort of machete). Good thinking or not?

3. Figuring double temper 400/425 for the O1, perhaps 500 for the 5160 since it will be an "impact" blade. Also going to torge draw backs of both. Again, good or bad plan?

Thanks, and sorry for the long post

Bill
 
That temper will give you about 58 Rc for O1 and about 55 Rc for the 5160. Soak time for O1 might be better at 10 minutes. "torge draw backs" do you mean differentially temper the spine in the forge after normal temper ? It's ok if you think you can control it well enough with the forge ....There have been some recent discussions about getting small amounts of quenching oil, did you search for that ?
 
Shane Justice 307-673-4432 sells Texaco Type A quenching fluid, a slow oil. I have found no quenching oil to pull the best all around performnance out of 5160. His address, PO box 251, Sheridan Wyo. 82801
Good Luck
 
Here is a big 5160 I edge quenched in Brownell's Tough-Quench that turned out good:

Preheat: ramp rate / 500 F, hold at 1150 F / 5 minutes (I don't know why I only preheated 5 min.. I usually hold for 7 min..)

Austenitize: 1525 / 9 minutes

edge quench in preheated 125 F oil

Temper: 400 F / 1 hour

Temper: 375 F / 1 hour
----------------------

RL
 
Thank you all for the advice thus far! Mete, I meant "torch" draw back , not forge - not much of a typist!

If I can't find the AAA oil, I'll try the tough quench or the Texaco A , I guess. You all seem to agree that a "slow" oil, rather than the Park #50 is better, though


Roger, why the pre-heat - I thought you could just go right to the austenitizing temp on the oil hardening steels?

Thanks again

Bill
 
From the relative little I believe I understand, the preheat helps to get the entire cross section equalized in temperature. During preheat the steel tends to expand. During austenitizing the steel contracts. If all the cross section is not equalized in temperature during the austenitize soak some parts may expand while others contract. I have not learned of any reason why the steel hardening type (deep, medium, shallow) would have any difference in this theory.

I believe, but don't know how to word it, over preheating can also cause problems. I usually ramp at a moderate rate to preheat and hold there for 7 minutes; then ramp balls-to-the-wall to austenitizing soak.

RL
 
I see you have forged and normalized the pieces so things should work, but if you are working with the O1 in the factory annealed condition, I would increase your soak by a couple of minutes at that temperature. There are a lot of carbides to dissolve in speroidized O1. Almost any good quench oil should get you to full hardness without the shock you could get from #50. Though you are correct, AAA would be my preference.
 
Hi guys,
You know, we've always had trouble maximizing the 5160 outcome as well. O-1 is so easy to heat treat it has really spoiled us. If the 'A' quenchant is warmed, I can't see any risk in quenching O-1 in that.
 
The past six months I have enjoyed the opportunity to re-explore the performance potential of 5160, using what we have learned through 52100.

There is a lot of theory and thought surrounding heat treat.

I have one thought to present. When you hear of a heat treat, ask the one who presents the thought how his knife performed. ie How many edge flexes, How many cuts on hemp rope and how many 180 degree flexes the blade made. Achieving the first 90 degree flex is childs play compared to the potential of quality steel. Test yourself, ask why, keep records and always use a reference knife in the cut test. You will now know how well the heat treat worked. No theoritical explanation can over come the knowledge available to the bladesmith through testing his own blades doing what they are meant to do in his shop using his own hands.

This is the key to the art of bladesmithing, science can offer information, but like in testing the accuracy of a rifle, there is no substitute for the X ring at the desired range.
 
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