In this picture you can see a little bit of the pattern coming through.
And a rack full of knives.
I need to do 2 more cycles, one at 1500f and then 1450f. This takes quite some time. Each time I soak the blades 10 minutes. I do more than one blade so It goes a little faster but still took a few hours. The importance of doing this thermal cycling is to improve the grain structure of the steel. It also stabilizes the steel after the heat from forging and grinding.
Next I turn the salt pot back up to 1500f and start the soak again. Need to soak another 10-15 minutes after the salt temp stabilizes. I only put 3 blades in this time. It is hard to capture the quench by myself. So I did not even try. I pull the blade out of the salt after the soak and it has to go straight into the quench tank. Edge down and as straight in as possible. I use a commercial quench oil for my heat treating. Here is a shot of one of my quench tanks.
So what could possibly go wrong? This is arguably the most important step in the knife making process. I tell people you can take a mediocre steel and nail the heat treat to make a great knife, or some high end steel and screw up the HT and have a crappy knife. This is why I like to use known materials in my blades as much as possible. Most steels like a slightly different process. Whether it be the quench temperature or in the tempering. The steels I used like the same temp for the quench but a slightly different tempering process. If you do not get the temperature right before the quench ie too low, you could have a soft blade, Too high it might be brittle or even crack. You also need to know the quench medium. I have some steel that is water quench steel, though I use a very fast oil. Water is not forgiving at all. Heat treating is very important in the knife making process. I cannot stress this enough.
A little oil smoke in the shop.
Here is an oven full of quenched blades going through their first temper.
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