Is it 1084 from NJSB David? Have you done a little bit of grinding on the blade right after quenching? You may be dealing with a decarburization issue. Feels soft to a file, but grind off a few thousandths on each side and it can be a totally different story. Also walk us through your heat treat process from forging to normalizing and so on.

Brion

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Is it 1084 from NJSB David? Have you done a little bit of grinding on the blade right after quenching? You may be dealing with a decarburization issue. Feels soft to a file, but grind off a few thousandths on each side and it can be a totally different story. Also walk us through your heat treat process from forging to normalizing and so on.

Brion

It's a blade I forged with you in August, from the 1 1/4" stock, so yes I believe the steel is from NJSB. I normalized it in three cycles, the last one being the darkest red I could still see in the shop. Then it sat around for two months while I got my shop put together, although I've been filing and sanding it (no grinder yet).

I brought it up to heat by heating the tang first (it's a full tang) then turning it around and moving it in and out of the forge, trying to keep the heat even. On the first (failed) quench I tested on the magnet, then back in the forge for a few seconds, then quick as a flash into the quench. (I got the 81mm mortar shell can you suggested.)

The decarburization is interesting. Like I said, no grinder, but I could try draw-filing it down. Think that's my next step?

Try this.

Bring just the end of the tang up to heat and quench; maybe a little over heat, it is just the tang.. Carefully break off the last 1/4 to 1/2 inch in a vise. It snaps clean or it bends. Will eliminate a lot of guessing.

If it bends; not enough heat or not enough carbon.

If it snaps clean; your process on the blade is flawed. Will the very tip of the blade snap off after quench?

After" 5 or 6 tries " I would imagine you have some serious decarb.

Using the blade as a learning tool now is of far more value now than finishing the blade.

M

And relax a bit. You do NOT! need to get that steel in the quench under a second. That's the time the OIL has to drop the austenizing temp down to about 900 degrees. Getting in a hurry like that can cause unwanted accidents.

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And relax a bit. You do NOT! need to get that steel in the quench under a second. That's the time the OIL has to drop the austenizing temp down to about 900 degrees. Getting in a hurry like that can cause unwanted accidents.

🙂 I'm not rushing. The quench is within arms reach of the forge so I just pop it out and pop it in. I was just trying to clarify that I'm not walking 20 feet or anything so I don't think the problem is that the blade is cooling.

what kind of file are you checking with? some of the new old stock nickelsons are made from VG10 steel and are well over 64 rockwell they will cut any hardened carbon steel.

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what kind of file are you checking with? some of the new old stock nickelsons are made from VG10 steel and are well over 64 rockwell they will cut any hardened carbon steel.

It's a chainsaw file. I wondered about that, which is why I tested using both a heat-treated blade and a piece of un-heat-treated 1084 stock.

I haven't had a chance to get out to the shop this weekend, but next step is to try to break a piece of the tang off, as Mike suggested. I'll have to re-quench (again!) because I already tempered it.

I think the problem may be in this area:

"I brought it up to heat by heating the tang first (it's a full tang) then turning it around and moving it in and out of the forge, trying to keep the heat even."

Can you use a baffle tube to heat up to quench temp? This would allow a much more even heating of the entire blade.

This might seem like a silly question/input.....but time and experience has taught me it's worth asking.....

WHERE is your quench tank, in relationship to the heat source you're using for hardening? When there is a temp specified with a given action involving steel, it means that the steel MUST be at the specified temp, WHEN the specified action occurs. In this case, the steel must be at it's austinizing/critical temp WHEN IT HITS THE QUENCH OIL. The description you gave tends to make me think that you're either loosing, or are not achieving the needed temp before quenching. Personally, I don't even consider tangs when it comes to heat treating..... I prefer to leave them in an annealed state.

If your heat source it too far away from the quench tank.... you're likely loosing critical heat before you get to the quench.

1084 is one of those "get it hot, and get it wet" easy to heat treat steels..... so if nothing above applies, then it's time to look elsewhere... too much forging?