Work hardening 5160 vs. 1080

B

byersj79

Joined
Nov 17, 2007
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156
It seems like 5160 is easier to work harden than 1080. Is that true? I had a few blades that was annealed two 1080 and three 5160 that I needed to stamp yet. I heated them up last night and stamped all them and bent one of the 5160 hidden tang blades. I figured I could bend it back by hand without heat and broke off the tang. I wouldn't even call that working the blades really all I done is heat them up to a low orange and stamped them. It seems like the 5160 air hardened a little. Is that a characteristic of 5160? I didn't try to bend my other blades but plan on cutting some strips today of both steels and experimenting.
 
stamping shouldn't have work hardened the blade enough to cause it to break.

how sure are you that it was properly annealed????
 
never try to bend cold. Without knowing what your definition of "orange" is I cannot intelligently interpret what your localized heating did to the structure of the steel, but you may have locally hardened it, or if you got it hot enough induced local grain growth. Any sharp bottomed scratch or the stamp would have been a stress riser

-Page
 
5160 can air harden but not to the point like A2 or D2 does... obviously these were blades that had already been profiled and ground right? if so were they forged? or ground out?... if ground, was the steel cold rolled or hot rolled? did the tang turn red while grinding? I routinely find hard spots in hot rolled knife steel. not as much (but it is possible) in Cold Rolled

Jason
 
Ok i just got my stamp so I'm inexperienced in this step. I have been forging, then flatten, clean up and rough out a little on the grinder, heat back up, stamp, normalize, anneal (I turn off forge and leave the blade in there for at least 5 or 6 hours usually overnight with the holes plugged), then finish out the blade, heat treat etc... Should I be doing this another way? These 5 blades were ready for the heat treat but I wanted to stamp them anyway but was surprised that it got so hard after. At what temp do you get grain growth? And if I get the blade too hot can I normalize to reduce the grain back down or is it ruined? Isn't that what normalizing is for or have I been forging too hot to begin with? My whisper baby forge doesn't get very hot but I know I stamped above critical. Thanks for your help.
 
5160 and 01 will air harden if heated to red. With 01 it is enough to cause drilling problems. It is the chrome that probably that causes it.
 
your slow cool might be giving you pearlite banding, several normalizations at succedingly lower temps will help refine your grain

-Page
 
LRB said:
5160 and 01 will air harden if heated to red. With 01 it is enough to cause drilling problems. It is the chrome that probably that causes it.
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I totally agree the chromium in the 5160 will cause it to harden if taken to an orange color.
 
On annealing forged blades you need a cooler or box with a sealable lid full of vermiculite, or DRY ashes, or both. get a scrap piece of 1/4" x 2 ( an old leaf spring works great...) and roll it up as tightly as possible... put it in the forge and get it WELDING HOT! next scoop out a half of your vermiculite, bring your blade up to red on the last normalizing heat and place the roll and the normalized, but red hot blade together, in the cooler. Dump the rest of the vermiculite on top of it, close the lid, and come back tomarrow. I've also heard of guys shoveling the hot coals on top of the blade as well and then dumping the rest of the vermiculite on top. The rolls job is to keep things nice and toasty in there with all that mass to retain heat.

Jason
 
Thanks guys for the help. I have the basic understanding of what happens with the steel during the forging and heat treating process but I have a lot more research to do. Part of the fun though.
 
You are lucky the blade broke when you were working with it instead of a client.

I well remember the first blade I broke, since then I have broken 100's and learned from each one. I do warn you, testing can be habit forming!!!
 
Ed Fowler said:
You are lucky the blade broke when you were working with it instead of a client.

I well remember the first blade I broke, since then I have broken 100's and learned from each one. I do warn you, testing can be habit forming!!!
Click to expand...

Yep I'm really glad. That's one of my biggest fears as a knife maker.
 
One thing you will learn is that all 5160 is not the same. I write about this in the Feb. issue of Blade. When you etch your blades you will gain knowledge about your heat treat and the nature of the steel you are working with.
 
I will for sure pick up that issue then. I read a lot of your website Mr. Fowler and will be ordering a copy of your Knife Talk II book here after the holidays. Thanks guys and have a safe and happy New Year.
 
stephanfowler said:
stamping shouldn't have work hardened the blade enough to cause it to break.

how sure are you that it was properly annealed????
Click to expand...

I agree with Stephan here.
I personally stamp my 5160 after I normalize it three times (of course to magnetic north), and then after the third normalizing. I bring the 5160 up to non-magnetic, and just a little bit past that. Then I slowly lower the air blow to the forge, and stack coal on top of the blade to slowly over night anneal it. I visit the forge ever few hours to throw some more coal on top to ensure at least seven hours of slow heat maintenance.

The next morning I do all my filing, and touch ups to the steel. Then I stamp the blade with my initials, or custom stamps etc. I dont necessarily "HOT" stamp the steel. It doesnt seem necessary when it is properly annealed especially with 5160. So I'm not sure what exactly you are trying to stamp, and why you have to bend the tang to do this, but a good deep stamp on 5160 right after you pull it from an overnight annealment is more than satisfactory for me. You can belt sand it a few times and still have a very deep stamp.
 
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