Heat treating 01 tool steel..... help

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shalegreenjeep

shalegreenjeep

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Would like to get some good info on heat treating 01 tool steel. Have been researching it on the web and the info varies greatly. Just doing small blades, mostly 1/8 inch.

Do I bring it up to 1500 for 10 min? Just past the point when it loses it magnetic.

What type of oil would be best olive or ATF?
Oil temp 125?
Do I raise and lower the blade for oil circulation, or just let it be?

Temper it how many times and for how long? 350 degrees?

Thanks, Scott
 
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The only change I would make is use the temp of 1550 as it will cool fast before hitting the quench.
 
I go 1500 deg. for 12-15 min. You may want to increase your temper to 400. If fully hard, this should be around 60-61rc which is still plenty hard. For a heavy use knife, you may want to go up to 425-450. Temper twice for 2hr each, cool to room temp in between.
 
Recommended temps are between 1450 and 1500 and hold for 10-20 minutes. I've been having good success with a digital oven (for accurate soaks) at 1475 for 20 minutes (to allow the blade to come to temp and then get a good long soak). Right now I quench in fresh canola, but I've got some AAA on order. As far as it cooling fast, it will drop temp like a rock, but you've got maybe a good second or so before things get too dicey inside the steel. Just quench smooth and fast and you'll be fine as long as the steel was fully at temp and soaked long enough.

I also temper at 400 for a general use cutting knife. Two, 2 hour tempers, with a room temp cool between.

--nathan
 
Nathan, what does it mean when instuctions for heat treating O1 say, for example..."10 min. soak time per inch of material."

I have been working with O1 also and wasn't sure how that would apply to something thin like a knife....

Thanks, Brad
 
10 min. soak per inch refers to thick pieces [more than 1"], but even tho we use thin cross section, you really should do the minimum soak time to allow all the elements to 'melt' into solution. This will create the correct condition for 'full hardness' without gobs of unmelted carbides.

And, don't call me Nathan! :eek::D:D
 
what i do is i heat the blade in my microwave for 20 minutes on high. then i soak it in crisco and cover it with plastic for 3 hours. after that i let it stand in a bucket of water for 3 days. i usually get a rockwell of 59. . im a jerk sorry only kidding--mark sorry
 
marekz said:
what I Do Is I Heat The Blade In My Microwave For 20 Minutes On High. Then I Soak It In Crisco And Cover It With Plastic For 3 Hours. After That I Let It Stand In A Bucket Of Water For 3 Days. I Usually Get A Rockwell Of 59. . Im A Jerk Sorry Only Kidding--mark Sorry
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Lmao!!!
 
Just for reference in the thread:

CRUCIBLE Tool Steel and Specialty Alloy Selector said:
Critical Temperature: 1370F(745C).
Preheat: 1250/1350F(675/730C)
High Heat 1450/1500F(790/815C), hold 10/30 minutes at temperature. Quench: Quench in oil to hand warm, 150F(65C)
Temper: 350/600F(175/315C); hold one hour per inch of thickness, two hours minimum, four hours preferred. (Emphasis added)
Click to expand...

Cryo benefits are mentioned, but not explicitly suggested. Quenching in oil from 1475F should yield 63-65RC as quenched. 400F temper gives the highest toughness in Charpy C-notch tests with a high hardness (61-63), no data on 450F. 500F will drop you down to 58-60RC with the same toughness as 400F which may be better for longer blades. None of the hardness and impact data mentions cryo being used, so I do not believe it was.

Full disclosure: I don't use O1, many folks here already know that. This data is straight out of the orange crucible book, your mileage may vary.
 
O1 likes to SOAK at 1450º-1550º F dont go overboard or anything but 20-45 minutes is fine think of it this way... At that temp, the carbon is getting into a liquid state, but like an ice cube in your drink it doesnt hit the glass and poof it's melted, it takes time, to melt, so it is with the carbon in steels. Also while ATF/Olive/Corn/Mineral oils are ok to quench with, and do infact work decently... if your going to go about it in a serious manner and quench alot over the next few months, get ya a gallon of either Parks 50 or Brownells Tough Quench to quench in they are DESIGNED to be used in this manner. It'll set ya back about $50.00 but it's worth it! anyway have fun and be safe

Jason
 
FWIW, #50 may be a bit fast for O-1 from what I've read. Maybe AAA would be a better choice for steels like O-1, 5160, 1070, 1080 and other oil hardening steels while Parks #50 is better for water quenching steels (W-series and 1095).

--nathan
 
I personally would not go over the 1500F maximum temps the literature suggests. It definitely needs to be held there for at least 10-15 minutes. Phillip Patton did a 5 HOUR hold at 1500F as a test and Kevin Cashen did micrographs that established there was no harm to the blade. Overtemp risks grain growth, especially when held. O-1 hardens easily, so getting it quickly into 125F olive or canola oil should get good hardness. ATF may be a bit faster than is necessary. (I would agree that a commercial oil is better for repeated use, but would rather suggest Park AAA over Park50 for this particular steel). You can raise and lower the blade, or make slicing motions. Avoid sideways motions.
According to the Heat Treaters Guide, optimum conditions should produce a hardness approximately HRc 65. Tempering at 400F should yield a blade with hardness 60-61.

Essentially the most heat-treating-knowledgable bladesmith around here, Kevin Cashen, has repeatedly stated his recommendation for following manufacturers' recommendations.
 
10xx series steels are generally brine or water quench, I'd stick with the fast oil for them.

Mike - I just wanted to verify that Heat Treaters Guide says 60-61RC @ 400F. Curious because you had me double checking my Crucible book.
 
AcridSaint said:
Mike - I just wanted to verify that Heat Treaters Guide says 60-61RC @ 400F. Curious because you had me double checking my Crucible book.
Click to expand...

I will email you the data sheets, Cap. Perhaps I have misread them as I listened to the continuing political drama tonight.

You'll notice that it allows a range of two points, and I have been slightly liberal lowballing it a small hair. (Considering these will be small blades, a slightly higher than lower hardness would be preferred, I would think.)
 
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Don't worry, I believe you ;)

Maybe Crucible found a way to make their steel harder (or typo their numbers). Or maybe the data is with cryo. Just curiosity, nothing more.
 
Ooops, I edited my post on you. Read my disclaimer, then read the charts. I used the graph on the the "c" page.
 
I use a salt pot to soak my O1 at 1500 F for 20 minutes and then quench into 400 F low temp salt, when cooled to room temp, I put them in cryo (liquid nitrogen for at least 4 hours). Since changing to this setup, I've found that my blades tempered at 400F are not passing the brass rod test. I've gone to 450F and still had chipping issues. (Note, I'm using some pretty thin edges.)

I have a batch I'm working on right now that I'll hopefully get a chance to test this weekend. I've tempered this batch at 475F, we'll see how they do. I've had to go to a 500F temper in the past but worry that 500F may be too high. I wish I had a RC tester.

Does anyone temper there medium to small size 01 blades at 500F?
 
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