Getting a hamon to really POP in 5160?

So there ya are :)

I clearly know next to nothing ergo the inquiry. So far I really like what I am seeing
 
Very good Nick. I might be wrong, but I think your FeCl is removing the layer of decarb. If you continue to do short etches it will get down to the hardened steel and be the same color as the top portion. I suggest fully removing the decarb as it doesn't have the rust-inhibiting and wear properties of hardened 5160. But you will still be able to take artistic advantage of that "shelf/step" with forced patina and strategic polishing. I like that you are experimenting... that is the spirit of a true artisan.

Rick
 
Rick Marchand said:
What???? Is that even possible past 2-3 cycles???? I'm cornfuzzled.
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He would start reducing cycles at 1500F, drop 50 degrees cooling to black with each cycle until he was down to 1200F

then he would austenize at 1450 (if I remember correctly, whatever AUS temp he used was VERY specific) and quench normally
 
stephanfowler said:
He would start reducing cycles at 1500F, drop 50 degrees cooling to black with each cycle until he was down to 1200F

then he would austenize at 1450 (if I remember correctly, whatever AUS temp he used was VERY specific) and quench normally
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So that would be about (3) good grain refinement cycles and some basic subcritical anneal runs. What ever the process, if it works, it works, right?

I think I misinterpreted reducing(heat) cycles with reducing(grain refinement) cycles..... my bad.
 
I've never tried for a hamon on 5160 so I can't wait to see what Nick does with this blade. I too am glad to see Nick experimenting with new things. IIRC Nick is doing all this with a 1x30 and doing a pretty good job. I can't wait to see what he will be capable of once he gets a more powerful grinder. Keep up the good work Nick and good luck on that hamon.
 
Rick Marchand said:
Very good Nick. I might be wrong, but I think your FeCl is removing the layer of decarb. If you continue to do short etches it will get down to the hardened steel and be the same color as the top portion. I suggest fully removing the decarb as it doesn't have the rust-inhibiting and wear properties of hardened 5160. But you will still be able to take artistic advantage of that "shelf/step" with forced patina and strategic polishing. I like that you are experimenting... that is the spirit of a true artisan.
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Thanks for the suggestion. I've been selectively polishing and etching as you describe, and it's come out pretty neat. I can't quite get the tone as dark as I'd like, as you suggested, but if I polish the portion outside where I've been etching, it stays silver, and the etch has taken on a bit of a greyish patina. Right now I'm working on my filework for the spine. Never be afraid to try something new, right?

Darrin, I'm hoping for a new grinder in September, once the USAF starts paying my wife with her HPSP medical scholarship, and she can start helping with our rent. I'm indeed still using a Rikon 1x30 sander, which is doing pretty well, but the platen is very short, and on a blade this size, ends up gouging the steel in the polishing phase. So that all has to happen by hand. It's not quite as pretty as I'd like, but still is pretty shiny. I'll probably put up a bunch of process pics, as I've been consulting with BePrepared throughout this process. I'm glad he seems to be having as much fun as I am.

Incidentally, for some reason, 5160 seems to be much more difficult to drill than 1095, particularly larger holes (esp the lanyard hole). Always a learning process, for sure.
 
5160 is pretty bad about spot hardening.

make sure to use a sharp bit, good quality cutting oil, and the correct speed on the drill press.
 
Yeah, the slower the better. I find sometimes that too thick of a cutting oil can contribute to work hardening. Soluble cutting oil at 1:10 water works well for drilling touchy steels for me.

Props for grinding that big ass kuk on a 1x30!
 
Thanks for the tips, I definitely think I could stand to get some better cutting oil. Hard to find in the hardware stores near me though.
 
Salem Straub said:
Yeah, the slower the better. I find sometimes that too thick of a cutting oil can contribute to work hardening. Soluble cutting oil at 1:10 water works well for drilling touchy steels for me.

Props for grinding that big ass kuk on a 1x30!
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actually "the slower the better" is a common misconception. I thought the same thing until NathantheMachinist mentioned in a post a couple years back that the more common problem is actually feed rate *(how hard your trying to push the bit into the metal) if your not getting curlycue shavings your probably doing it wrong.

there are plenty of cheap machinist handbooks that will give you optimal drill speed and feed rates for tool steel and you'll be surprised at how fast the bit should be spinning for a 1/8" hole
 
Just my metallurgical take on all this:
5160 is a deep hardening alloy steel. Give it three, ten, or three hundred cycles, and it will still be a deep hardening alloy steel. Unless I totally misunderstand the science of metallurgy, cycling the steel will not make it shallow hardening.
The thing that will change in ten cycles over three is the depth of the decarb layer.
If part of the steel was covered in clay and the blade cycled many times, you would have the san-mai two-tone look shown in the photo. This would be because the exposed steel would be lower in carbon than the covered steel. It would etch a different color, and polish less. If the decarb layer was sanded away, the blade would look more even toned, with at most a subtle line showing.

This isn't to say that someone hasn't attained a beautiful two-tone blade with some method or another in 5160, just that sometimes the explanation of how it was accomplished may be wrong.

That said, I want to see how this blade turns out. It looks very nice, and I hope BePrepared is not put off by our questions and comments. He is having a knife made for him , and will be surely proud of it...regardless of how the look got there.
 
Ehhh... I prefer slow feed and speed. Trashes less bits. The charts in industry handbooks sometimes are authored from a hardcore production point of view. I remember Nathan saying that as well, I recall it actually fairly often when drilling and watching the spiral chip, it's absolutely true... I just find that I tend to work harden alloy steels much more often at higher cutting speeds. Often the tangs I'm working on will not be fully annealed but normalized, or roughly spheroidized. Still a bit air hard. Another thing Nathan said IIRC is that some cutting lubricants can lead to excessive rubbing, leading to work hardening. I find that true as well. That guy is a good resource!
 
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