Hopefully some of the REALLY smart people will be along to give you some more answers. First off, great job doing so much homework on your process. Having a good plan is the beginning of ending up with a good result. Heat treating our knives is definitely a debated subject and you're likely to get a few different answers from folks. In regards to a few of your questions, I'll give you what I do.

For the normalizing after forging is complete, I do three cycles, beginning just a bit above critical as you have mentioned. But, I do descending cycles-meaning the 2nd time is lower temperature than the first and the 3rd is lower than the second. The way I've understood it is these descending heats help refine the "grain" or internal structure of the steel. So far, I've had decent results doing it that way. Also, I have gone to doing only one normalizing cycle instead of another 3 after rough grinding. I think I read somewhere that a second set of 3 doesn't end up helping all that much...? But, on the flip side of the coin, I really don't know that a guy would lose or hurt anything by doing it.

For the annealing you're talking about, I bring it to non-magnetic and make sure the whole blade is there (thicker parts like the ricasso, etc.), then put it into the vermiculite. In other words, I don't hold it at temp for any particular time before the vermiculite. That being said, there are different annealing processes (that I'm not very well versed in) that is much easier to do with a heat treating oven with different temperatures and times that can really help with some different steels.

For the hardening, you're likely to get different thoughts, as well. Some makers like lower or hotter temps, some always do a soak, others don't like to soak the blade at all, just enough heat to get the blade evenly up to temp, then quench. Go with what you want to try/what a mentor suggests and see how the results are. Your 10xx steels require a faster quench than 5160, or I should say it's more important for 10xx to get cooled quicker. There is less alloying in those steels and so you can miss that window more quickly before the internal structure reverts back. I finally just invested in some Parks 50 so I knew things would go well. I know people who have used Canola oil very successfully with 5160. If it's what you have, try using it for both your 10xx knives and 5160. I may be remembering wrong, but I think I remember reading a post some time ago from MS Cashen that said peanut might not be as good a choice as Canola...

Your tempering process is also very subject to opinion. Some temper once, some twice, and some three times. Whatever you choose, tempering is a process ruled by both time and temperature. Experiment a bit and see which works best for you. Starting at the temps and times you've mentioned wouldn't be a bad way to go. I personally do 3 temper cycles in the oven. But that doesn't mean any knife I make is better than one done twice.

I recently finished 5 knives-an astounding number for me. There are 6 others that didn't make it and 2 others that I can still work on finishing. I've got a significant amount of knives that have made it for different reasons into the "bucket 'o shame". I break some of them and otherwise test and check them. Any opportunity I have to see what my processes are resulting in, I want to know. When your finish grinding ends up with something "unrecoverable", it's frustrating, but use the opportunity to learn how your heat treat came out. Those are some of the best chances to gain confidence in or decide to change how you're doing things.

Good luck and I'm sure some other good folks will be along before too long with better answers <img src=' http://www.americanbladesmith.com/ipboard/public/style_emoticons//smile.gi f' class='bbc_emoticon' alt=':)' />.

Jeremy

Thank you Jeremy! I really appreciate your response!

John

John,

If you can't find your answer here on the forum under heat treat, then you can go to MS Kevin Cashen's web site. He has the info on all the steels we use. I refer to it often when trying a new steel that I haven't worked before.

Best,

Bob

Thank you Bob, I'll check it out.

John

|quoted:

I've taken lots of notes from the Forum and want to be sure I have it right. Please tell me if I've missed something or gotten something wrong.

1. Forge at 1400-1800, starting on the hot end and later forging at the lower end of that temperature range.

2. Normalize at 100 degrees above critical and air cool on a rack. Do this 2-3 times. (1450-1500 for 10xx and 1500-1525 for 5160) How long do you hold it at normalizing temp?

The temps listed would make this simple thermal cycling and not normalizing. Normalizing involves heating above the UPPER critical temperature and this is largely determined by carbon content. Heat to 1575F to 1600F and then air cool. The idea of real normalizing is not to make grains finer but to homogenize the internal condition of the steel, uniformity can actually be more important than size. This is then followed up by cycles like what you describe to refine the size. Normalizing is much more important with steels that form more carbides.

3. Anneal at 1250 and slow cool in vermiculite. How long do you hold it at annealing temperature?

With steels that have more than .8% carbon you can simply heat to 1250F-1275F repeatedly or hold at the same temp for an hour and then just let it cool. With steels that have less than .8% carbon you can do the same or heat to nonmagnetic and then do the vermiculite thing.

4. Rough grind and do file work.

5. Normalize again.

Normalizing is a bit of overkill. A simple stress relieve may be enough- heat to 1250F and air cool. You will have less decarb and scaling this way.

6. Harden by heating to critical and quench to <350 degrees, straighten if necessary. For 10xx steels, 1450-1500 soak for ~3 minutes and quench in 100-130 degree canola oil. For 5160, 1500-1525 soak for 10 minutes and quench in 130 degree peanut oil or vet grade mineral oil. Quench tip first and move up and down. Use thin layer of satanite if hamon desired.

It is important to try to quench to around 450F and not 350F. 350F will rob you of any auto-tempering benefits and could encourage retained austenite by interrupting the momentum of the martensite transformation.

7. Check hardness.

8. Temper. Cycle twice for two hours each time. 400 degrees for 10xx or 350 degrees for 5160.

350F for blades that will be fine slicers and 400F or better for blades that will be larger choppers, but this needs to also be gaged by the carbon content and how much of it you put into proper solution. Start low and then walk it into the hardness you desire.

On soak times. Simply obtaining temperature will open up the paths for the carbon to move, it will then take time for it to do so, and more so if the bonds with carbide forming elements need to be broken. The simpler the steel and the closer to .8% carbon the less critical soak times become. Controlled soak times will benefit almost any steel, only if you lack temperature control do you need to worry about things like grain growth or over-austenitizing, as these things are caused by overheating and not proper soak times.

^^^ I learn every time I read something from you, Mr. Cashen. Thanks for always taking the time to explain these things.

Jeremy

Thank you very much for your replies! It is a great thing that we have access to so much great information and that's due to so many who are willing to share their knowledge.