Strange issues with steel (1095)

H

HellFire Blades

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Aug 29, 2016
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I was working on a knife today and came across an issue I've never had. I'm very very far from experienced so I thought I would see if anyone had any ideas. The blade is 1/8 in 1095. Ground the initial bevels and gave to a friend to heat treat as he was going to a shop that had an actual oven and I just use my forge. He heat treated four blades for me. Two of which I've finished without this phenomenon and all of which came from the same bar of Aldo's 1095.

As I got into the higher grits I noticed almost a hamon-like spot in the blade. I finished grinding the blade and then hand sanded it to 1000 grit. After which it was acid etched in FC. I left it in the FC for 30 seconds and pulled it out to find, what I can only describe as, a weird hamon and ... lightning bolt looking thing. No crack... no scratches. Just this really weird finish. I scrubbed the blade with acetone and re-dipped it for about two minutes and they were both still there. Looked like this.



It goes through the whole knife.



Anyone ever had this happen? Any idea how it happened? Any way to fix it? Is the blade ruined? Certainly wasn't done purposely. It was heated in a programmable oven and quenched in parks. Can't say if there was anything done to cause it. Wasn't there.
 
Hey from looks of it man it looks like it wasnt quenched in a fast enough oil. you etched it for 2 min you might have some pitts in your blade and might have to grind the thickness down a little more to get rid of em. Your blade shape looks good tho. Id personally sand it shiny to about 600 grit and see what you can still see.
 
Bob From Accounting said:
Hey from looks of it man it looks like it wasnt quenched in a fast enough oil. you etched it for 2 min you might have some pitts in your blade and might have to grind the thickness down a little more to get rid of em. Your blade shape looks good tho. Id personally sand it shiny to about 600 grit and see what you can still see.
Click to expand...

It was quenched in parks 50. Outside of water, I don't know of any faster medium. It was ground to 800 on the grinder, including the flats. Then hand sanded from 600 - 1000 then dipped.

Should I completely regrind the whole knife and redip?
 
It looks like an unhardened portion on the blade. Polish it with some flitz or mother's mag polish, and use it as is. I think it will look neat.

Otherwise to get rid of the spot, you will need to redo the heat treat.
 
Hrm... well fnrom your etch the unhardnened portions are nowhere near your edge so you will be good to go and finish it like alexander said. I just did some 1095 blades and had some weird unhardened spots that i discovered at 600 grit that were higher up. Id go ahead and finish up that bad boy. :D
 
HellFire Blades said:
I was working on a knife today and came across an issue I've never had. I'm very very far from experienced so I thought I would see if anyone had any ideas. The blade is 1/8 in 1095. Ground the initial bevels and gave to a friend to heat treat as he was going to a shop that had an actual oven and I just use my forge. He heat treated four blades for me. Two of which I've finished without this phenomenon and all of which came from the same bar of Aldo's 1095.

As I got into the higher grits I noticed almost a hamon-like spot in the blade. I finished grinding the blade and then hand sanded it to 1000 grit. After which it was acid etched in FC. I left it in the FC for 30 seconds and pulled it out to find, what I can only describe as, a weird hamon and ... lightning bolt looking thing. No crack... no scratches. Just this really weird finish. I scrubbed the blade with acetone and re-dipped it for about two minutes and they were both still there. Looked like this.



It goes through the whole knife.



Anyone ever had this happen? Any idea how it happened? Any way to fix it? Is the blade ruined? Certainly wasn't done purposely. It was heated in a programmable oven and quenched in parks. Can't say if there was anything done to cause it. Wasn't there.
Click to expand...
Say Heah, I might be wrong, But I don't have too many knives in the 1095 because I feel that the 1095 Carbon Steel is Recycled too many times and I believe this does something to tge steel, Like it looses some of its integrity. I like the 1095 CroVan much better, Alot of Companies get a great price on the Recycled 1095 that's why they use it, Sure they can Temper it good, But I still feel it's lost some of its integrity. My $00.02. Thanx You. ,, .

Sent from my SM-N900T using Tapatalk
 
Your blade was:
a) not hot enough.
b) not soaked at temp long enough.
or...
c) not cooled fast enough to avoid the pearlite nose.
(1095 needs to be agitated in quenchant..even in a fast oil
like Parks 50).
 
Russ Andrews said:
Your blade was:
a) not hot enough.
b) not soaked at temp long enough.
or...
c) not cooled fast enough to avoid the pearlite nose.
(1095 needs to be agitated in quenchant..even in a fast oil
like Parks 50).
Click to expand...

Makes sense. Sadly I wasn't there so I can't pinpoint which one is the culprit. The real question is, do I buff it clean and redo the heat treat then regrind the knife or just leave it as is? It's finish ground and ready for an edge. Will it be too thin to heat treat?

Forgive my ignorance, I'm still pretty new to this whole thing.
 
Aldo's 1095 has fairly low manganese and no chrome...which is great for forming hamones, but
also makes it shallow hardening...so t can be fairly picky about hardening.
I'd suggest checking the edge with a file..if it doesn't feel as hard (very subjective) as you think
it ought to be....re-heat treat.
If it seems hard enough...sharpen it, and do some cutting before deciding to procede or re-HT.
 
Last edited:
It looks like you were going for a hamon anyway so if you have a spot that didnt harden all the way thats exactly what your going for id say polish it a LITTLE to see how she looks then if your serious about putting out a great product or gift (and dont mind the extra sanding) sharpen it and do some testing
 
Well, couldn't find any soft spots on the cutting edge so. I hand sanded it to 1000 grit again and then hit it with a light buff. Figured I'd post a finished product for those that were kind enough to chime in and help.

Thanks for the input!


Be gentle, I've finished less than half a dozen knives.



Thanks again for the help.
 
One cause of this is warmed parks #50. It should be used at room temperature - 70-90F. Heating to 130, as is done with most other quenchants, makes it slower.

Alloy banding and an auto-hamon are common in 1095 and W2 if the soak wasn't long enough, or the steel wasn't properly normalized. In these shallow hardening steels, a small change in time, temperature, and quenchant can make noticeable changes in the appearance.

As Don said, it is common, usually considered a good thing, and the edge is fine.
 
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