damascus steel blade is 54 Rc .. good enough

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kdiver58

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Sep 20, 2010
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I used Alabama damascus steel to make a blade. After heat-treat and draw it checks 54 Rockwell C on a certified tester .. Is that going to be hard enough or should I re-Heat-treat it?
 
Rc 54 is hard enough for a knife, and many commercial knives are about that hardness. A lot of the lower priced pre-made and hardened damascus blades from overseas, and sellers like Alabama, are Rc54-55.
Today, with better steel and better HT, most custom blades are made to about Rc58-59.

I have noticed that Alabama damascus often comes out a bit on the lower side. I just tested a blade for a friend who bought a damascus billet from Brad and Lacy, made a nice knife, and had me do the HT on the blade. He felt he could get a file to bite on the edge after HT a bit more than the 1084 blades from the same HT batch, so I tested them. The 1084 blades were all Rc58-59, but the Alabama damascus blade was Rc55.

This does not affect how sharp the blade can get, or the strength of the blade. It only affects the edge retention. Such a blade will need to be sharpened more often if used regularly. The vast amount of damascus blades never get much use, and thus the Rc hardness isn't really much of an issue.
 
I thought that damascus which included unhardenable steels like 203 would often times read funny with a hardness tester. Often times several points lower, but the surrounding hardenable steels would really be full hardness.
 
Not hard enough, IMO. My damascus blades(1084/15N20, O1/L6; quenched in Parks 50 and AAA, respectfully), I would have to TRY to get such a low Rockwell. Usually, my blades end up around 61 after tempering at 400-425 and I have to force myself to go upwards of 450 to get them closer to 60 Rockwell.
 
I have a small Paragon furnace. I heated the blade to 1550 degrees F and let it soak there for 10 minutes. I then quenched it in McMaster Carr 11 second quench which was heated to 200 degrees. I did a draw at 400 degrees. The knife started in the oven on the way up to 1550. I'm wondering if my Pyrometer is reading higher then the true temp.
 
The only problem I see with the HT is heating the oil to 200F . It should be heated to about 120-130F. I doubt it would have affected the blade steel you used that much, but you could do a second HT and see if there is an increase.
 
Also what oven did you use for tempering? When did you put the blade in? Blade in cold oven then ramped up? or oven sitting at temp for ten minutes then blade put in? also was the blade perfectly perpendicular to the Rockwell testing anvil, and diamond?
 
200* is too hot for your quench..About 125* is good for mcmaster carr..Not sure if that accounts for 4-5 points of hardness though? I wouldent leave it at 54rc..Shoot for 58-59 if you can..
Do you happen to know what kind of damascus it was? 1095/15n20?
 
Alabama damascus can be many mixes. It was 1095/203E, 1095/5160/203E, 1095/15N20, and a dozen other mixes.
 
Material = (4) layers 5160, (3) layers 203E, (3) layers 52100, (3) layers 15N20.
I placed the knife in the furnace and turned it on to heat treat it.
I have another small oven I used to temper the knife it was at 400 degrees when I placed the knife in.
 
bladsmth said:
Alabama damascus can be many mixes. It was 1095/203E, 1095/5160/203E, 1095/15N20, and a dozen other mixes.
Click to expand...

kdiver58 said:
Material = (4) layers 5160, (3) layers 203E, (3) layers 52100, (3) layers 15N20.
Click to expand...

Brad's stuff typically starts out with 416 layers. This is, of course, prior to blanchard grinding to final thickness. Because of the steels used in the mix, I would venture to say that if you took a billet and hardened it (no grinding of bevels, just the straight billet), and did 20 Rockwell tests on it, you would probably get 20 different readings.

Keeping in mind that with a mix, as described above, you can only hope to zero in on the hardest section of the final mix when testing. Because of layers, upon layers of different steels, I doubt that a hardness test will give you much useful information.

Whether it performs as expected is the final test. Basing the worth of a damscus knife soley on a Rockwell Hardness test is chasing an elusive dream.

Robert
 
IIRC, the "sweet spot" for the 11-13 second Houghton oil (which I believe McMaster-Carr sells with their name on it like Brownells does) is 150F. that gives you the 11 second rating. If you go up to 180 or down to 120, then it is a 13 second oil. Anything above 180 and you are out of spec in theory. As for you original question, I am with Danbo in this one. 54RC is not even remotely close to good enough.
 
54 Rc is NOT good enough for a custom/handmade knife. No matter how pretty the blade is, it won't hold an edge worth a hoot. Other than that, I'm not qualified to comment on the steel/HT process you're using.
 
I agree with Robert. Damascus is a different creature, because of possible differences in penetration hardness (and/or properties) between layers of different materials. Even though the carbon may diffuse or "migrate", some of the other alloy constituents won't. So, depending what's in the mix, what quenching medium was used etc., a Rockwell test may or may not be very useful. An extreme example would be a very fine grained Damascus mix of high carbon air hardening steel and wrought iron.

... another good example of how industrial standards don't always apply.

As side notes, I also think that certain alloys can hinder carbon diffusion/migration,... but you'd have to check on that. Also, a scratch hardness test wouldn't be any better than penetration or vice versa.

Impact testing at various angles (or chopping), shock, edge holding, toughness, (springiness or rigidity etc. depending), etc... tests are what's needed.

... "macrostructure" tests.
 
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... even though Damascus is a creature of it's own, I think there's an important lesson to learn from it which applies to all steel and/or knives.


... The inevitable importance of the "macrostructure". :)
 
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