heat treat O1 in a kiln questions

AJH_Knives

Well-Known Member
I put a digital controller on my kiln and it takes 3 hours to hit 1500* if I put my blades in and let the heat ramp up to 1500* will that be okay. I will let them soak at 1500* for a while before quenching.so they can potentially be in the kiln for 3.5 or more hours..
 
Wow, if it takes that long, you need to take a look at your kiln.

What would happen if you wanted to ramp from say 1200 to 1500? Would that take another 3 hours?

"Soak for a while" ???? How long is a while????

One of the main things that I have learned over the years is "Controlled" temperature, time at temperature, and quench medium and techniques according to the specific steel you are using.

Again, I don't think you mentioned what type "Kiln" you are using, but I would certainly take a look at it if it is taking that long to reach temps.

Robert
 
robert, the unit i have is probably from the 50's and the oven inside is about 16x16x16. it is huge, and weight is about 100 lbs. i just thought because of the thermal mass it took that long to heat up???
 
The reason we're scratching our heads is the slow temp ramp speed. Most of us doing O1 in a kiln would put a blade in a 1500F kiln - allow it 5 minutes to equalize -and then let it soak 20 minutes then quench. (or something similar). The problem is that O1 is kind of "in the zone" somewhere around the 1475 to 1500 mark, so where do you start counting your soak if it takes a looonnngg time between those temps. Also, very long exposure to high temperature can cause decarb, so some type of protection would be appropriate. Normally excessive temperature is the risk, but time can take a toll as well.

In any event, I think most of us agree that 3 hours is too long, so anything you can do to minimize exposure would be helpful.
 
My kiln is 110V. i will power it up and wait till it hits 1500* before I put the O1 in. then i'll let it soak for 20 to 30 minutes total.... that sound good?
 
01 really should not go over 1475° for the soak/quench heat. 1500° can cause a loss of some of the benefits of the extra carbides that form. On a different note, if you will hold down the alternate key, then strike 248 on the numbers board on the far right of the keyboard, you get the ° degree sign.
 
My kiln is 110V. i will power it up and wait till it hits 1500* before I put the O1 in. then i'll let it soak for 20 to 30 minutes total.... that sound good?

Yup. Sounds good. I still use Turco, cause I like the cleaner blade, but I don't imagine 20 - 30 minutes is going to hurt much.
 
Another way, which is the only way that it works with my machine, to get the ° sign is to go to the character map off the run window and highlight the ° the click on select then copy all you will have to do is right click where you want the sign then click on paste. That ALT 248 has never worked for me. Maybe it a Windows 7 thing that doesn't allow it.

As far as heat treating O1 goes, you could try both 1475° and the 1500°. People can have different results with different equipment. What you're aiming at is getting enough carbon into solution without so much into solution that you will have a lot of retained austinite formed. Here is a place that it would be nice to be able to have the freshly hardened steel tested for hardness.

Doug
 
I am using a Windows 7. The numbers to use are the 248 in the separate block of numbers and signs group on the far right side of the key board. The alternate key must be held down as you type the sequence in.
 
Thanks, I'll give it a try °. Yea, it worked!! Now if I can find that list of other codes and tape them to my machine.

Doug
 
That is the only one I know. If you find more, I'd be obliged if you would post them.
 
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