Brandon

I have an article by our Founder Bill Moran that I posted on the ABS Website that may answer some of your questions, click: http://www.americanbladesmith.com/uploads/file/Techniques%20Master%20Class/Heat%20Treating-%20Moran.pdf

What steel type are we talking about?....that makes a specific answer easier. It would also be helpful to know what you're using for the quench (what type of fluid).

In general, in order for the types of steels we forge, in order for it to harden, it must go from it's austinizing temp, to 400F or less, in 6 seconds or less. That can vary slightly depending on steel type. but it's a good rule of thumb to follow.

That being said, when I teach edge quenching to students, I teach students to start with the point/tip/belly submerged, for a slow count to seven, then rock the back portion of the blade into the oil, slow count to 7, then repeat.... until all the fumes/smoke stops. Once that occurs, then I drag the blade off the "limiter plate" and submerge the entire blade in the oil until it's cool enough to handle.....then it gets the oil quickly cleaned off, and into the tempering oven.

The biggest issue that I have discovered over the years is people not understanding that the blade/steel must be at least at it's austenizing temp WHEN IT CONTACTS THE QUENCH in order to fully harden. Example: I've had a couple of individuals that I've gone back and forth with on the phone, trying to help them figure out why their blades were not fully hardening.....come to find out that they were heating in their forges, which were about 10-15 feet from their quench tanks.....by the time they got the blades from the forge to the quench, they blades were way below the austinizing temp. Just something to be aware of.

For many years I used straight mineral oil as a quench, and made it through both my JS and MS tests with it.....not until just a few years ago did I start using commercial quench oil....and still keep a tank of mineral oil in the shop, just because I know how it works, and I trust it.

Thank you for the replies. I will read the article. I am using 1084 with parts 50 to quench in. I can get the blade super hard but the whole blade. I bring the blade to 1520F and hold it for 2mins then quench. from what you wrote i am submerging the whole blade way to soon.

Another thing to be aware of Brandon, since you are using 1084. If it is from Aldo's last batch. The manganese content is like .7 or .8. This means it will behave as a deep hardening steel. Consequently even with edge quenching it may get hard farther up than what you were intending. Great steel but not for hamons. I think Ed gave you good advice, but you will have to play around with the quenching process in order to get what you are after.

Brion

I don't want to muddy the waters from the good stuff already said.

From what you've described, you need a slower oil. Parks 50 will pull the heat out of 1084 so fast it'll harden way above the oil line, like Brion said.

|quoted:

I don't want to muddy the waters from the good stuff already said.

From what you've described, you need a slower oil. Parks 50 will pull the heat out of 1084 so fast it'll harden way above the oil line, like Brion said.

What would be a slower oil. I used to use canola oil.

|quoted:

What would be a slower oil. I used to use canola oil.

The Canola is what I would stick with for edge quenching, for reasons already mentioned but you will trash your #50 with edge quenching. Parks #50 has a flash point significantly lower than most other oils, edge quenching will most likely result in catching it on fire, this will rapidly oxidize the oil and fill it with sooty particulates. I assume you got my reply to the e-mail so that the rest is covered, but edge quenching into #50 will be an expensive lesson to learn, not to mention dangerous to boot.

Edited to add- 1520F is tad high for 1084, 1500F is the highest you really want to go.