ABYMC

T3sl4 · Posted: Thu Feb 14, 2008 2:23 am Post subject:

Rebar is typically A36 or something not much better. There are grades, but one might assume the crappiest grade. An average composition might be around 1050 or 1060, which will quench harden, but not as hard as 1080-1090 does. You could carburize it (or Kasenit, etc.) to get better edge hardness.

For starters, bang out a bar into a flat, put an edge sort of thing on it, work it into a recognizable knife shape, then harden and grind it. Don't go for welding so quickly. You need a hot fire for welding anyway.

Hardening is done by heating just past the temperature where the steel becomes nonmagnetic (its Curie point), then quenching in an appropriate medium. Some high carbon alloy steels need to be held at temperature for some time, to make the mixture of alloys come together; regular steel doesn't need this. Do NOT overheat, and do not keep it hot any longer than you need (maybe a few minutes to get the temperature even). If you do, you'll cause crystal growth which means brittle nasty metal, no matter how much you temper. The only fix is to forge it all over again, mushing up the crystals. Any plain carbon steel needs to be quenched in water; you can use brine and other additives to improve quenching action, which will help with lower carbon steels. Most alloy steels (like OCS) need to be oil quenched, and some high alloy steels only need to be air cooled to freeze in the hardness.

Once hardened, the steel is as brittle as glass. You should play with a small piece to see just how much treatment it can stand. Bend and break it, see how hard it is (I'm not sure if it'll scratch glass..), that kind of stuff. To temper, put it in the oven at 300F for an hour. This will give a reasonable knife hardness. If you ground down the surface to bare metal, you'll notice it's now colored straw or purple or something: this is normal.

I don't recommend tempering with a torch, because the color "runs" much slower than the actual tempering. You will inevitably end up with an edge burnt by flame, and material overall excessively tempered.

The final product should be flexible (if thin enough), bendable without breaking (D'OH!), and hold an edge for a reasonable time (a few weeks of normal usage?).

Keep it clean, and keep it away from hard materials like glass, ceramic, metal, bone, etc. You should get skilled at sharpening your edge as well; I can usually shave myself (not too smoothly, I'll admit!) after a good sharpening. I like a stone of around 200 grit, which gives a ragged yet fine cutting edge, good for slicing stuff. (A real razor needs a very steep and finely polished cutting edge, BTW.)

Tim
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Anon · Posted: Thu Feb 14, 2008 4:12 am Post subject:

metalmaster1766 · Posted: Mon Feb 18, 2008 3:29 am Post subject:

Jim Hrisoulas books are very good, i have 2 and if you are interested in knife making i recommend his book The Complete Bladesmith

heat treating at home is the most difficult part of knife making, you need to know what metal you are using, and know the critical temps for each step involved

heat treating gets even tougher when doing pattern welded blades, because of the different properties of metals used to get a pattern

i had a tough time getting my 1st pattern welded blade heat treated properly, i had to try many different quench's to get it right, (took 4 tries to get it properly hardened and tempered)

Ron

Spacebot · Junior Molder Joined: 24 Oct 2006 Posts: 136

Hey, I've got questions about 'Damascus Steel'. I guess the simplistic history is that is was a really-high quality, multi-layered and laminated steel produced in (of course) ancient Syria, where a bunch of skills from East, Mid and West came together. From what i thought 'We've' 'lost it' as in modern metalworking doesn't know the original materials or methods used to produce it. However, there is TONS of internet literature claiming to make it: What is so special about this steel and do we really know how to make it?

metalmaster1766 · Posted: Fri Apr 11, 2008 11:38 am Post subject:

nobody knows exactly how it was made,
what made it special were the designs made in the blades, well at least thats what i thought it was

it is said that a master bladesmith shows his true skills by creating patterns in the metal, at least that is what i have read over the years, many people have very different ideas about Damascus
like i said a few sentences earlyer - no one really knows for sure

the main 2 reasons i do it are,
#1 i love the designs you can make, it is endless,
#2 it is not as hard as some say it is,

i think it is rather easy, but then again maybe i made Damascus in a former life Laughing

oh yeah, laminated materials also have more strength , they say

Ron

Neil · Posted: Fri Apr 11, 2008 4:32 pm Post subject:

Damascus steel uses carbon nano tubes filled with cementite and ferrite carbide particles. The ‘Damascus steel’ you find referenced today is not even close. It’s actually pattern welded steel which has different carbide concentrations in the fold which produce the wavy pattern.

Recently the secret of the true Damascus steel was recently worked out. You need to have a steel that is doped with vanadium and you have to simmer it in a crucible for a long period of time. Then there is an extensive bought of pounding and forging before it is true Damascus steel. A metallurgist and a professional black smith have in fact recreated and produced small amounts of true Damascus in the USA.

They theorize that the original source of iron ore for the original Damascus steel was the key to the swords. Once the vanadium rich ore was exhausted… it became impossible to produce the steel and so the secret and knowledge of it was simply lost.

If you have a true Damascus blade you’ll find it’s enduring edge is the result of the softer steel wearing away leaving the almost diamond hard carbide filled nano tubes protruding from the cutting edge.

Hope that helps a bit ;o)

Edit: fixed some spelling
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Spacebot · Junior Molder Joined: 24 Oct 2006 Posts: 136

Oh Wow. Where did you find all that out? The stuff about the nanotubes... is that just produced as a result of the solidifying of the steel?
So people use 'Damascus Steel' to describe any kind of pattern welded and laminated steel, not necesarily the real stuff...

Neil · Posted: Fri Apr 11, 2008 7:47 pm Post subject:

T3sl4 · Posted: Fri Apr 11, 2008 9:13 pm Post subject:

LOL, no. Not nanotubes.

The slow solidification (we're talking crucible steel here, it's cooled slowly in the crucible) produces large crystals of cementite. Needless to say, it takes a high carbon content (1.5% or so, whereas most carbon steels top out at 1%) and carbide formers (vanadium is great for this, as is chromium and others) to make cementite instead of cast iron (if there were enough silicon and/or phosphorous in the alloy, it would make gray cast iron instead). So actually we're almost talking white cast iron here.

Pattern welding is unrelated to Wootz, but producing a pattern is a byproduct of the manufacturing process. Etching the surface (which, after grinding and polishing, is probably as plain silver as a homogeneous steel billet) brings out slight differences in metallurgy, either as regions of carbides or as regions of differing composition (e.g., nickel or chromium-rich layers) as is used for most pattern welding today.

Tim
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Neil · Posted: Sat Apr 12, 2008 1:55 am Post subject:

Here

or else

Random blog

Journal of nature abstract
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T3sl4 · Posted: Sat Apr 12, 2008 5:11 am Post subject:

Hmm, that's new research (since I heard anything about Wootz some years ago). I may have to dig into that...

Tim
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Neil · Posted: Sat Apr 12, 2008 12:08 pm Post subject:

Theoretically if you could heat the mass in a crucible under a highly compressed atmosphere of hydrogen you could riddle the steel with nano-diamonds! I think you only need a 'mere' 10,000 or so psi...
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T3sl4 · Posted: Sat Apr 12, 2008 4:58 pm Post subject:

The Gemesis process does that, turning graphite into diamond using molten iron as solvent.

Such a product would be quite wear-resistant, but wouldn't have much advantage for strength (although I shouldn't be so hasty in saying that, it would block slippage planes like precipitation hardened materials). I bet it would (permanently) anneal easily -- who wants to bet iron is an excellent catalyst for reverting diamonds back into graphite?

Tim
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metalmaster1766 · Posted: Mon Apr 14, 2008 12:32 pm Post subject:

i have read many things about Damascus and Wootz steel, from what i understand Wootz is the closest to true Damascus, but then again, what the hell do i know

one thing you may notice is, i never ever call any of my knives Damascus, i call them what they are, and that is - pattern welded knives/blades

Neil, those are some interesting articles you put up, thanks, ill hafta spend some time and read them over better, thanks

Ron

Heimo · Posted: Mon Jul 07, 2008 5:16 pm Post subject:

Hi all just thought I'll tell you guy a real good knife steel is called n690 stainless and a outer one is 12c27 my dad is a knife maker and this is considered the best steel available (that we know of) for this purpose this metal is so hard it can't be drilled an a large drill press after it is hardened the drill bit dulls before it makes a mark on the knife
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