View Full Version : Heat treat ?

12-11-2009, 03:43 PM
I am about ready to heat treat my first knives! Since I melted my homebuilt oven down, I will do it at work. At work, we have two ovens. They were both just recalibrated, and will work great. I plan on making a rack and doing four blades all at once. Blades are o-1 tool steel that I will bring to 1475 degrees, for 10 minutes and quench in about 140 degree oil. Don't have the real quenching oil, so will have to use something else. What oil would work best.
I will let them cool to 125 degrees, and temper for two hours at (not sure) degrees. What do you recommend? I will than let them cool to room temperature, and temper again. What do I want on the rockwell? We do have a rockwell tester.
We also have stainless foil, Is the extra expence worth it?
This is my first time doing something like this. I just want to get it right. Don't want to see all my work go down the drain!:eek:
Any changes to my recipe or advice would be much appreciated.
Thanks in advance!!!

Nathan The Machinist
12-11-2009, 05:44 PM
O1 isn't picky about oil type, but it needs a good soak at temp. Once the oven is at temp, the steel needs to hit temp. After the steel is at temp it needs to soak at least 10 min. Don't worry about over soaking it, you could leave it in there all day at temp. I'd leave it in an oven that is at temp for 20 min.

O1 (with a thin section like a blade) will achieve full hardness in any oil.

Foil is a pill for an oil quench steel because it makes the quench difficult.

Agitate like you are chopping with it to reduce warping. An interrupted quench helps reduce warping also. You can pull it out after about 8-10 seconds to finish in air. Tweaks can be made to straighten it while it is still hot, preferably around 500F on the way down during the quench.

12-11-2009, 06:29 PM
Thanks for your reply!!!
Good to hear o-1 isn't picky on quenching oil.
My thoughts on the foil are the same... Would be nice to use, but what a pain to get it done in time.
How much warpage can be expected? Guess I should be prepared to deal with it.
I am shooting for a rockwell of 58 to 60. What are your thoughts on that?
And what would be a good tempering temperature to achive this?
Thanks again...

12-15-2009, 08:47 PM
Just got back from work, I stayed late to HT my first 4 blades. Went perfectly! Tempered at 450 degrees, no warpage, and Rockwel tested to 59 when finished. Very, very happy.:D Should have some pictures to post soon.