[Otto Karl]

I was reading a lot about Japanese sabers on vacation [yeah, about folding steel and something more] and then I came to this page and saw that blade: how in the world do they made that odd looking black steel? Do anyone of you have a single clue?

The page is http://www.wkc-sports.com/Blackheartofdragond.html

[Dustin R. Reagan]

[Shayan G]

Would it be the same for real Damascus, not just pattern-welded? I saw this tulwar in the Victoria & Albert museum, the flash makes it look light but it was really almost black. It was gorgeous:

[Dustin R. Reagan]

[Brian Johnson]

Greetings, I am a custom knifemaker/swordmaker and am new to this forum. I hope I can be somewhat of a resource here. The black color on the damascus blade is likely to be just an etching technique. After damascus steel is forged and ground, it must be immersed in an acid solution (I use ferric chloride) that targets one of the steels present in the blade. The less acid resistant steel is eaten away to some degree and the other steel is left nearly as it was. This leaves the blade slightly textured. A black carbon deposit accumulates on the surface of the entire blade. After the acid etch, the blade is usually final polished to remove the carbon deposit from the high spots on the blade (the more resistant steel). This results in a nicely contrasting shiny pattern over a dull gray background. The blackened blade shown in the picture looks just like my blades do before I do a final polish.

p.s. by "damascus" I mean pattern welded. I have no experience with actual wootz type steel.

[Robin Palmer]

While I agree with Brian that is one method of bringing up the pattern in many cases the process of grinding and polishing will bring the same results. I suspect the V&A swords colour may also be caused by centurys of oiling which will darken the steel over time. Given its age I doubt the V&A will want to re polish it.

As to the black Katana my bets on gun chemical cheap and quick plus requiring no great degree of technical ability.

[Otto Karl]

Boys, a katana has to be polished an regrounden it´s whole life because non aleated steels tend to rust so much. It means that a cosmetic surface treatment is not desirable for such weapon; so, the steel is black itself. The question is now "Do you know some sort of black steel and it´s composition?" Because it is more probable this steel is that way.
And yes: I know carbon do tend to evaporate and accumulate on the surface when the steel is heated, but it woud be awful if the blade decolorates after polishing.
So... Anybody know a source of black steel and the way it is made?

[Shayan G]

Thank you Mr. Reagan, Mr. Johnson, and Mr. Palmer--those were helpful answers! I was wondering about that sword for the past two weeks since I visited the museum!

As an aside, Vince Evans has some black pattern-welded blades on his photostream. I'd reference his website but I don't know about bandwidth etiquette or copyright issues...a googling for "Vince Evans bladesmith" will suffice!

[Jared Smith]

[Brian Johnson]

Otto, I have never seen a naturally black colored steel. If the color is not a surface treatment, then I am just as curious as you are.[/quote]

[Aloy Diaz]

That shiny black katana might just be chemically treated, looks like the finish in a Berretta 92f (brunitron finish or something). True black steel (if ever there is such a thing) is just steel that has a lot of impurities in it, this is the reason why some old Katana's and a lot of Philippine swords produced in antiquity are coloured black... The antique japanese katana had to be folded and refolded to hammer out the impurities (take out the slag) as the smelting process used in the past was inferior (there was always some slag left)... this is also why antique japanese swords have a wood patern (if you look at them closesly you will see grains on them, the thin black part that makes up the lines producing the wood grain is just plain slag that was never hammered out by the folding and refolding process)... same with the antique Philippine blades - the metal also had to be folded and refolded to get rid of the slag. Of course the Japanese were more sophisticated sword makers and such they were able to hammer out more of the slag and produce better blades... Philippine blades do tend to be darker (just more slag left in the metal) and a bit rougher..

[Jon H.]

[Adam Bodorics]

While I'm not an expert on steels, I've never found a steel which is black by material. I searched, as I prefer black over any else color, but I failed. Even wootz, which can sometimes be VERY black is shiny if grinded.
BTW, AFAIK oxides are not a bad thing if they are covering the entire surface - they'll stop most other oxides appearing. About regrinding... I don't think reoxidating would be a hard task for someone who made it before.
...
Jon H.: While I never tried blackening treated steel, I frequently oil blackened my mild steel armours. Even if the oil reached only a reddish state, the plate softened a bit, and making the oil layer black needed a higher temperature. About heat discolorization: if the heat used is under the recristallization heat, it wouldn't change steel properties in theory. But I'm not sure if cca 300 °C is enough for blackening.

[Brian Johnson]

300 degrees Celsius / 570 degrees Farenheit is not hot enough to blacken steel without the use of oxidizing chemicals. This is near the upper end of the tempering scale for most commonly used sword alloys. Any higher temperature can severely diminish blade performance. Typically, steel will take on a dark grey color if heated to around 1000 degrees Farenheit or above, but rich black oxides cant effectively be formed without the use of some kind of chemical aid. The following website has a handy chart that illustrates the colors that can be attained within the tempering range of steel: http://www.anvilfire.com/index.php?bodyName=/...colors.htm

[Dustin R. Reagan]

[Glen A Cleeton]

Is it just possible that the original poster's reference was alluding to iron bearing black sand (magnatite)? From which tamahagane is smelted.

Just a thought

GC

Never mind, yes an etch.

[James R.Fox]

Guys-read up on George Cameron Stone Arms and Armour etc. O.K. he was wrong about wootz steel, but none of the smelting sites in India and China had been found, let alone cleared by experienced metallurgists when he wrote his book..So,he only recognized folded steel He had, and cites,with a photograph,a Persian dagger that was yellow and blsck,divided in a straight line down the middle of the blade.I was going to look up the page number for you,but then I thought that everybody needs to read George on a regular basis or they will never be civilized.It is in one of his sections on Persian blade smithing.He says the type of steel with impurities that made it yellow or black was produced in Khorasan, and he had seen it before, and it is produced by impurities in the ore.While I agree the the medieval persians were the greatest blade smiths ever on the planet or any other, the fact the he does not recognize that they are using wootz steel, not folded steel makes me suspect some of his statements about metallurgy.I realize the is gross heresy, and will turn myself in to the thought police in the morning.

[Otto Karl]

[James R.Fox]

By the way I looked at the Blackheart page, that is after-coated steel. You can get it from Windlass Steelcrafts through MRL and other outlets as well. As far as I Know, steel colored black at forging is as George Cameron Stone said-it's made from impure ores which he says can be obtained in Khorasan Persia (Iran)

[Dustin R. Reagan]