Thread: O1 heat treating problem

Sure looks good, hate it that it just has no soul. I've done it quite a few times my friend. Last batch of knives I made I warped one, tried to straighten...snapped it. Best I did anyways, it was grainy.

Originally Posted by shooter74743

Sure looks good, hate it that it just has no soul. I've done it quite a few times my friend. Last batch of knives I made I warped one, tried to straighten...snapped it. Best I did anyways, it was grainy.

I am sorry about it.

If it were mine, i would do a couple of things. I would take it to a coarse stone (not grinder) and take 2-3mm off the edge by honing at about 45 degrees. Then re-hone and shave.

If it is still a bad HT, you can still learn from it. Make a pattern off it. Then, if it were mine I would put it in a vice straight up and down and break it in the vice to see what the grain is doing. That way not all is lost and you can "see" what is wrong.

Originally Posted by shooter74743

... I would take it to a coarse stone (not grinder) and take 2-3mm off the edge by honing at about 45 degrees. Then re-hone and shave.
...

I will do this and I will see.

In addition I will make a simple razor fort test.

My plan for the HT:

I leave at least 1 mm (3/8") thikness of the edge.
soaking: 805C / 1480F, 8-10 min.
quenching oil: 50-60C / 130F, 30-60 sec
tempering: after cooling to room temperature, 205C / 400F, 2x1h (between cooling to room temperature) or 1x2h

What do you think? This should work, isn't it?

Tim Zowada wrote about this:

"
First, the blade must be properly normalized and spherodize annealed. Then,

If using a gas forge, for O-1:

1. Heat to 1500F - All "shadows" are gone. No soak at temperature. It is too easy to overheat in a forge. This is why I would prefer 1084 or 1095 over O-1 in a forge.
2. Immediatly quench in warm (160F/70C) oil (Park AAA) - rapid agitation of blade.
3. Interrupt quench when blade reaches about 400F/204C (pseudo martemper)
4. Air Cool to room temperature.
5. Temper at 380F two times.
"

My question is the 3. point. How importance to interrupt at this temperature? What is the significance of this?

Originally Posted by gregg71

3. Interrupt quench when blade reaches about 400F/204C (pseudo martemper)


My question is the 3. point. How importance to interrupt at this temperature? What is the significance of this?

Interesting. I just read a bit about martempering in Verhoeven's book. It helps prevent quench cracks. I will have to give this a try. Might be a bit tricky to interrupt at the right time though

An other guy's recipe. Sorry but I dont rememeber hes name, I copied from SRP.

"Heat to 1450 F and hold for 15 minutes. This is called soaking, and it allows the carbon to dissolve back into the iron.

Quench in Parks AAA quench oil, preheated to 130 F. This is a slow cooling oil. You could also use vegitable oil or any number of other oils, but this stuff was designed specifically for heat treatment. For about $10 a gallon, I'd rather just use the best.

After a minute, take the steel out and allow it to air cool. When it's cool enough to touch, put it in the oven to temper it. I temper at 425 F for two hours. Allowing the steel to cool down in one hour cycles isn't necessary."

One minute or less? Cool enough to touch: this is the room temperature or higher?

Originally Posted by gregg71

I will do this and I will see.

In addition I will make a simple razor fort test.

My plan for the HT:

I leave at least 1 mm (3/8") thikness of the edge.
soaking: 805C / 1480F, 8-10 min.
quenching oil: 50-60C / 130F, 30-60 sec
tempering: after cooling to room temperature, 205C / 400F, 2x1h (between cooling to room temperature) or 1x2h

What do you think? This should work, isn't it?

NO. 1mm is smaller than 1/16", 3/8" is equal to 6/16" which is way too thick for final grind. .

I would leave my rough grind about 1.5 to 2 mm, which is between 1/16 & 1/8". Our measuring system here in the U.S. is not near as good or simple as the Metric system. With this being a worldwide forum & Americans being the oddball out when it comes to measuring, most of us here on this forum can work in mm & cm pretty easily. Heck, I've even gotten better and I am a bit slow.

I believe any of those HT recipe's would work if your rough grind blade edge would be thick enough to hold the heat until the steel hits the quench.

Yes, sorry. 1/16" = 1,59 mm. For me much more simple to use the Metric system.

Than I will grind it about 1.5 - 2 mm. I jus read that somebody is leaving the total thickness before the HT: ~6 mm. Thanks!

While we can discuss this till the cows come home, if the blade doesn't shave, I would remove the scales. They are nice. Then clamp the blade in a vise with the shoulders so that the blade section sticks out, and hit it with a hammer to break it.

What will happen will give you a lot of information that you really need in order to understand what went wrong, and what you can do to change it. Most people here who make blades will break them sometimes to learn from. While it is a shame to break a blade that is 'finished', it will also teach you things you cannot learn otherwise.