How to fix screwed up 1084 HT?

Chiro75

Chiro75

Joined
Feb 4, 1999
Messages
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I tried to HT a blade that was WAAAAYYY too long for my crappy setup. I ended up only getting a zone about 1/2"x2" up to critical, then quenched. I'm hoping to fix it this weekend with Laredo7mm's help, since he has real tools, forge, etc. But, what do I do to fix this sucker? It's 1084.

I assume I need to anneal it (how do we do that? Temp/time?), then once it cools I can clay coat it and bring to critical and quench as normal. Please advise so I don't waste anyone else's time. Thanks!
 
I'll probably get in trouble with the experts .... again, but.

Assuming you just didn't get the hardness you wanted and 'screwed up' doesn't mean you burned the steel, I'd just triple normalize and call it good. Don't know of a reason to anneal first.

Steve
 
Steve is right, 1084 is pretty forgiving in heat treating. What you've done won't hurt at all. What martensite you did manage to form will just act as nucleating points for finer grain when you re-heat treat it. Like Steve said, normalize three times and then quench, no need to anneal it at all.
 
Heat it until it's non-magnetic and then air cool it. It's a good idea to do this before every quench, even if you're not fixing a previous mistake. It makes the grain smaller and removes strain from the steel making it less likely to warp.
 
Yup, what AwP said.

The trick is getting the blade pretty much non-magnetic without getting the edge to orange hot. Otherwise you'll have larger grain right where you want to refine it. Well that's the same problem as heating for the quench isn't it?

I've resorted to cheating on this part. I heat treat forged blades in an electric furnace so no part of the blade over heats. But a good bladesmith can do it in a forge or with a torch just fine.

Steve
 
I'm having Laredo7mm do this with me this weekend, and he has some fancy schmancy salt thingamajig, so I imagine even heating will be no problemo! Thanks!
 
Salt bath - yeah baby that's the ultimate!

Tell him you want each normalization cycle to drop the temp by 25 degrees from the previous.

Also, stay in your car while he fires it up. That should afford enough protection.

Steve
 
Sando - What do you mean have him stay in the car? I was going to have him "watch the pot" for me while it heats up. :D :eek: :D No, it is some scary stuff, she spat up a few times the other day when I fired her up, but it had been a while since the last heat up so she absorbed a bit of water. She should be in fine shape for the Chiro's tanto.

I typically triple normalize at 1650°, then at 1600°, then at 1550°. I then austenize at 1550° and quench in warm oil. I assume this will be good for 1084, but I typically work with 1095/15N20 damascus.

I have never done clay before either. How do you all think the clay will hold up in the salt bath? How long does it take to dry? Can we dry it in the oven at 350° and then go to the salts?

Thanks for the input guys, this is going to be fun.
 
Laredo7mm said:
I typically triple normalize at 1650°, then at 1600°, then at 1550°. I then austenize at 1550° and quench in warm oil. I assume this will be good for 1084, but I typically work with 1095/15N20 damascus.
Click to expand...

That is so cool - you've made me green with envy ... again.

I have my own method :eek: . I heat the oven to about 1600, then soak for 5 minutes and bring it out to air cool. Of course when I open it the oven temp drops, then back in for 3 minutes. Repeat.

Each time I loose some temp in the oven. Same effect but no where near as controlled as you get.

Steve
 
Worst case scenario is that we kill a knife that is already dead, anyway, so let's see what happens. I'm bringing my digital camera with me, so if anything crazy happens I can snap a photo. :D
 
Chiro75, if you are still having problems after the first of the year, let me know. I will post this more prominently on the forums, but in the next month I would like to start to get MI makers together and start sharing information and communicating more. I have discussed it with some of the smiths that I know and they are ready for it. I would like to have a bimonthly (or what ever we can manage) get together that could travel to different participating makers shops. I would be willing to have guests at my place first, if it will get things rolling.

Laredo7mm, due to you interest in Ken Mankels get together, I assume you may be interested in us all getting together as well. Let me know what you folks think. And if you want to play with treating 1084, we can try all kinds of things with it.
 
Kevin -

That sounds great to me, I would definitely be interested in getting together with more MI smiths. Keep in touch with the details, I think you already have my email, but if not, let me know.

Chiro -

No worries, we will resurrect that tanto. The limited testing that I have done with my set up on 1095 is 62 HRC as quenched and then after temper it was 58 to 59 HRC. The worst that can happen is that we don't get the clay completely dry before it goes into the molten salt, if that happens we both might have some nice "war wounds" and hospital bills. ;)
 
After Laredo gets this one back on it's feet, you should make a forge. They can be made for as little as nothing to as much as you want to spend.
Part of the fun is to be creative.
The down side is that you have to learn how it's supposed to be done first. Then you can get the primal urges! :D
 
I'm jealous. I wish I lived in MI. This is a very generous offer by Kevin; anyone who doesn't take him up on it (to quote one of my former teachers) must be either crazy or insane.

John Frankl












i
 
As to the clay coat and salt. Nick Wheeler may see this and chime in, but he told me that's a dicey proposition at best. If the clay is not 110% dry it'll pop all over the place in the salt. I think it'd take a few days in a very dry atmosphere to get clay dry enough for me to risk it. But Hey! You guys have fun. Wear a lot of heavy clothing and face shields, etc. Be careful!

Can't wait to get off my dead and dyin to build my own salt pot. Then I'll be doing some of those long blades I keep dreaming of... Chiro take a lot of pics and share em with us when you can. This sounds like a great time.
 
KEvin, that idea sounds REALLY cool! I would be up for going around a bit and learning some things. I'll be the "team chiropractor" for MI knifemakers! ;)

Sean, maybe we should just clay coat the tanto and use your forge to bring it to critical. I'm not speaking from experience, but I assume that molten salts on the skin doesn't feel real nice, so I'd be up for doing it the old fashioned way if you have the equipment! :D
 
Chiro75 said:
KEvin, that idea sounds REALLY cool! I would be up for going around a bit and learning some things. I'll be the "team chiropractor" for MI knifemakers! ;)

Sean, maybe we should just clay coat the tanto and use your forge to bring it to critical. I'm not speaking from experience, but I assume that molten salts on the skin doesn't feel real nice, so I'd be up for doing it the old fashioned way if you have the equipment! :D
Click to expand...

:D wise man say,, knowledge is good. :)
 
If Sean has been working wth the salts I am sure he would be aware of this, but just in case... moisture in the clay would be a a real perilous situation to be sure, but the clay, even if completely dry will play havoc with the neutrality of your salts. Find a rich carbon source to hopefully counteract this or you will have nasty decarb on all your future blades done in those salts. It will eventually reach a point where heavy micro-pitting will cover the surface of the blade. Don't ask me how I know this :grumpy:
 
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