Trad Gang
Main Boards => Hunting Knives and Crafters => Topic started by: DANA HOLMAN on September 02, 2010, 08:55:00 PM
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Ok guys I'm really confused about annealing spring steel. I have one knife forged from 5160 spring steel. First time I had brought it up to around 1500 degrees and let it set in the forge over night to cool. Second time back to nonmagnetic and put it a bucket of lime and it was there for two days. This is the hardest steel I have ever seen. So can someone tell me where I'm going wrong
thanks
Dana
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Hummm.... I just started a project using 5160!
Wish I could help!
Wait til you try Cru-V :banghead:
Steve
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Potomac Forge
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If it's 5160, it should soften up even by just normalizing it a couple of times. I'll it bring up to non-magnetic/air cool, bring up to below non-magnetic/air cool maybe couple of times and it is soft enough to file & drill. Can you drill through it after you being it lime for a slow cool?
Lin, Karl, or some others can probaly figure it out...but it doesn't sound like 5160. Doc
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I don't know much but it almost sounds like some kind of air hardening steel.
Lin...Karl?????
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Dana,
It dont sound like 5160. Do you have any more info on it? Lin
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What does it sound like Lin? I did a blade from a plowshare that did the same thing. I then just got it a dark orange and let it cool. It was still kinda hard but i could work it and drill it.<><
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5160 can air harden. But, if you are taking steps to soften it, albiet it's not a true anneal, it should be soft enough to work. Are you trying to file it Dana?
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Lin
this is the steel Jeremy sent some guys to make knife and other stuff in his shop. I thought he said it was a leafspring from a international truck. I forged it into a knife but I can not grind it. It's got my head spining
thank for any info
Dana
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Dana,
If that was the same steel I got from Jeremy, it forged, ground, quenched, and temper just like 5160 for me. I must have gotten a spring from a Smart car while you got the Mack truck spring :biglaugh: Doc
(http://img.photobucket.com/albums/v110/tippit/Jeremy%20Knife%20Challange/JeremysKnifeChallange001.jpg)
(http://img.photobucket.com/albums/v110/tippit/Jeremy%20Knife%20Challange/JeremysKnifeChallange020.jpg)
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Dana,
You probably know this, but I have to cover all of the bases. The lime is just an insulator and dont affect the steel except holding the heat in the piece. This is your goal, to hold the heat in and let it cool slowly, as slow as possible. Try this, take two pieces of steel (mild steel is fine) and put one on each side of your blade making a sandwich. Tie it with something like heavy steel wire, but avoid non ferrous wires. Bring it all up to nonmagnetic (be careful not to get it too hot)and while hot get it into the lime or leave it in the forge (turn it off)and shut the openings and the fan off quickly. Let it sit for several hours till you can hold it in your hand. Wait at least 6 hours even though this is not a true anneal, if this dont show a significant difference, I doubt you have 5160.
By the way, what belts and grinder are you using to grind? Lin
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Karl had some good posts on O1 and 5160 a while ago in this thread: http://tradgang.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=110;t=001843
He talks about spherodizing just the area you want to drill with a torch.
The way I do the whole blade is to put it in my pottery kiln at about 1250 degrees for an hour and then turn it off to slow cool. CruforgeV and old sawmill blades work pretty easy after that treatment and it doesn't grow the grain.
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Lin
I'll try it today, the belt sanders I have is a 2x42 craftsman and a 1 x 30 grizzly. Tried it with a 80 and 50 grit belt.
Thanks again
Dana
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Dana,
Pick a spot on the blade that needs removal and grind enough of the scale off to reach it with a file. See if it will cut with a file. If it will, it's plenty soft enough to shape with a grinder. You may have to be patient with that small a grinder.
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The steel I sent out was all from the same leaf spring of an old international truck. It seems to be pretty close to 5160. Sounds like you're either not getting it up to critical (or are there long enough) to get everything into solution or a cooling it off to quickly.
Scale on the outside can be pretty tough to get through.
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Yep. It sounds that way to me too Jeremy. In fact Dana, if you're going straight to your grinder with scale on it, you are needlessly wearing out your belts. Get a side grinder to remove the scale I use a metal cutting wheel and change to a flapper wheel. Or soak the blade in muratic over night before grinding. Scale is hard enough to mess up a file.
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I think I will try that before I reanneal. You got it right about the scale, I've been taking it stright to the belt grinder. I'll let you know how comes out
Dana
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Dana,
I also got the same package from Jeremy. (Which reminds me I need to finish it up.)I just started a nice hot charcoal fire, tossed in the spring and let it sit till the next day and it was soft as butter. I will say that it was NOT easy to forge a blade out of, that is some TOUGH stuff. But, I didnt have any issues in annealing. Hope this helps, good luck buddy!
Kid
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Dana, I've been off on a canoe trip for a while or I would have helped you right away.
Pardon me for saying something - you said, "This is the hardest steel I have ever seen".
I hope not.
Your steel should be getting a LOT! harder when you harden your blades - right?
This is 5160, a very deep hardening steel, with a long time for martensite creation.
Jeff answered your question right in the third post.
If you bring 5160 up ABOVE! non-magnetic, and let it slow cool, it'll harden.
Not as hard as it might be if you quenched it in the proper oil, but it will air-harden due to all the chromium.
You will want to do this, like Jeff says, at least once after forging, because you always want your first post-forging thermal cycle done at your forging temps.
Maybe twice.
But see where Jeff says, "bring up to below non-magnetic/air cool maybe couple of times".
That's the method - "BELOW" non-mag.
That way, you are not making any austenite by going ABOVE critical.
Martensite won't form while cooling from a temp that is not above critical - you'll get pearlite.
Do it in a dark room and just bring your steel up to a dark red and a magnet still sticks and let cool.
Do a few times.
Sticking it in a bucket of lime for 2 seconds, 2 minutes or two days doesn't accomplish anything after going above non-magentic other than making your steel hard, if it's a deep hardening steel.
We toss this word "anneal" around way too loosely.
There's more than one type of annealing.
Lot's of guys stick their blades in the forge and let them cool in there, and that's just bad news.
Especially if it's a steel with more than .84% Carbon.
A person should NEVER! slow cool a steel that has more carbon than .84% from above non-magnetic.
And it's not a good idea to do it with steel below that much carbon, unless you WANT! martensite - like you'll get in 5160/O1/L6/52100.
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Karl and kid
thanks for the info. I had started on it and ran out of propane. I've got more now.
Karl that's what I was doing taking it to nonmagentic and in the lime for overnight cooling. I be back in the shop this afternoon and try again
thank again for your help
Dana
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You just want dull red.
Do NOT go above non-mag.
Then just let it air cool.
Do that three or four times.
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Karl
how much should I let it cool down, so I can hold it in my hand or until the color is gone?
Dana
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Room temp.
What is it - exactly - you are trying to soften?
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A piece of 5160 from a leafspring
thanks for the help
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I realize that - I read the thread.
Are you trying to make the blade or the tang more "friendly"?
Are you filing or grinding?
Why do you want it more machinable?
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Karl
I am trying to get the blade soft, so I can flat grind it. the reason I'm asking was, after I forged it, it was so hard that a new 80 grit belt would not hardly touch it. I annealed it two times today and waiting for it to cool to see if it's soft.
Before I annealed it I took all the scale off like Lin said. I'm going back in the shop and will repost what I find out
Dana
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There's really not much difference in grinding hard or soft steel at the 80 grit level.
You should hardly be able to tell the difference.
Scale was probably your problem.
We really need to be more careful with this term "annealing", especially when we use it in reference to steel with more than .84% carbon, as well as less than .84% carbon.
As well, slow cooling from above critical and below critical.
That right there is four entirely different animals.
And what are we "annealing"?
Hardened martensite or pearlite?
There's a whole heck of a lot more to it than getting a piece of steel hot and cooling it off.
If not done from the right steel phase at the right rate and temp, grain growth can just destroy all of your time and effort.
There are no short-cuts in this stuff - if you want to do it right.
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Ok I think I can put this thread to rest.
It's soft, it was probley soft but the scale was hard.
Thanks for all the help from everyone and I hope this helps others
Dana