I ground a blade today and put it my oven to austenitize 1525 F, 5160 double edge dagger. Electric fire brick oven ,(old wax burn out kiln.)

When I opened the door almost immediately the tip cooled to black about a 1/4" back.

It was ground pretty thin .030 or less.

Anybody have this problem or think of a way to get the blade to quench fast enough. I'm sure I can't grind that thin for one thing.

Mark

A very thin section will do that, as mass is needed to retain the heat. Try to harden the blade anyway and see if it works out, Else you may have to restart and try again.

Edited June 26, 200916 yr by steve sells

Thanks Steve
I did fumble on the way to quench and missed it. Try again today.

Well just like in annealing you can place sections with more mass alongside of the blade---just besure they don't go into the quench together!

Mark,
How far from the oven is the quenchant? I was having a similar issue because I was too lazy to move my quench tank closer to the forge. Finally just had to do it. I'm not suggesting you're lazy by the way. Just a question. I practice the move a couple of times as the piece is coming up to temp just to make the process go smoother. Kind of zenlike too.

I put this blade(5160) back in the oven to 1525F soak for 10 min. quenched in ATF at 140F.
Mike, my quench is 2-3' from oven ,arms length, did some practice,2-4 seconds to quench.

Came out dead soft.

Cut a piece of the bar it came from 1/4x11/4"and did the same procedure- dead soft.

I think I got some mild steel from the supplier.

Anyone willing to take sample of this to try hardening? I'll pay shipping.

I cann't help with the steel but here is a dodge that I worked out.
I clamped a file knife I was quenching between too pieces of mild steel to increase the mass and heated the whole thing. I pulled the mild steel off just the moment that put the file in the oil.

Of course you cold do a clay on the point and knock it off just as you go into the quench. Haven't tried it my self but ....?

I like that Charlotte, Great tip for when a steel splint is too large to fit in the given area !

I think you are austenitizing it too low or for too short of a time. Increase the austenitizing temperature to 1550F-1575F and hold it for at least 1/2 hour. Your forging probably grew some whopping big grains and large carbides so normalize it a couple of times too. Don't forget to grind the decarb off before you check for hardness, too. If that doesn't work, yep, mild steel.

It's a little warm today so I thought _ do a spark test
first pic, mild steel
second pic 5160, suspect steel
third steel 1084
They are not in this order in the gallery ,read "photo discription"
Let me know what you think Thanks Mark

BP 0020 covers spark testing. Your blade material does NOT look like a high carbon steel to me.

BP 0020 covers spark testing. Your blade material does NOT look like a high carbon steel to me.

At first I was going to agree...but then I looked closer at the pictures and remembered some spark testing I did on 2 different leaf springs I had found...I used some mild steel and an old file to sort of "benchmark" or whatever you want to call it...one spring, sparked almost like the file, and the other (which I have figured to be 5160) while it was noticeably higher than the mild steel, was also not even comparable to the other spring or the file.
Based on your pictures, I would say, in my "opinion" your "5160" probably is 5160...possibly you are just not hot enough ?? Not cooling enough ??
In any case after quench, it shouldn't be dead soft if you are getting it (and keeping it) hot enough before quench.
Just test a small piece at higher temp.
And, as Quenchcrack mentioned, be sure to remove the dacarb layer...it could be thicker than you think if you are spending so much time at temperature, depending on the atmosphere in your oven.
Personally, I wouldn't soak for 10 minutes on something thin like that.

Thanks Craig
I've sent a chunk of this steel to one of the experts here on the board w/ a nice size piece of 01 for his trouble but haven't heard back yet.

it was Mild, I am sending him some of my stock of 5160H from security steel.

After I performed a normal hardening process and getting nothing, I over heated to 1600F and soaked about 5 minutes then quenched into cold water slack tub, after it cooled to the touch, I placed the bar in vise and hit with my 6# hammer, it bent a little. thats it ... so it is only MILD

Mark if you are still undecided send me a sample long enough to pull from forge with tongs and i will dip it and RC test it. Send me a im if you wish and I will send addy. If you do send clean it up first I will hardness test before and coat it to prevent scale and test after.

Man...I knew I shouldn't have written that huge post ;-)
Oh well, some thoughts to ponder for next time I suppose...
At least we all know what it is now !!

Craig, Thanks for your post , all ways good to hear all comments and opinions.

Steve, Thanks for testing. I thought maybe that bump on the head....:confused:

Rich, Thanks, that's a generous offer. I'm gonna practice grind on the little bit left and get rid of it.