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Comment by qazpot | Hacker News Reader

Isn't knowledge of making Damascus Steel lost to the ancient civilizations or I am confusing it with some other steel?

There are a lot of steels called Damascus now, probably more accurately called Damascus Style. Basic idea is to keep heating and folding the steel, then hammer it flat, then heat and fold again and again. Then, once you fashion the knife blade you etch it in acid and it shows up all the striations from the folding.

Interesting patterns can also be made starting with lots of pieces of steel like a handful of bolts and you heat and twist them together.

Called the Hamon in Japanese sword making.

If you go to Birmingham Museum (the UK) One, they have an exhibit of swords from the late samurai period that have be re hilted by a guy who went to Japan and spent several years learning the traditional methods.

Hamon is not the fold patterning. It is the transition in crystalline structure from the differential cooling along the cutting edge.

Just to add on: the wavy hamon pattern is created by applying clay to the steel. When the blade is then quenched the clay slows the temperature change beneath it keeping that part of steel blade softer then the rapidly quenched cutting edge. The advantage of this was the soft spine would be tougher (less brittle) while the harder edge could be made sharper.

It was, yes. Today, many knife makers (including the parent comment) make pattern-welded steel by alternating high/low carbon steel. It's not traditional damascus or wootz. It looks beautiful, but it's not "real" damascus.

Here's a link where folks have 'rediscovered' how to make real wootz/damascus. It's the most academically rigorous attempt I'm aware of, and I'd call it a success:

https://craftsmanship.net/the-wootz-hunter/

Crucible steel techniques were always carefully guarded and never "public", but never really "lost". This stuff popped up regularly through history in various cultures, the Wootz smelters in south India were, I believe, still in operation when European colonizers were able to document the process. And by the mid 19th century it was fairly well understood by modern metallurgy.

It's just hard to do and requires a giant furnace. The folded stuff modern hobbyists are making looks almost the same and can be done in a propane forge.

As far as I understand, the interesting qualities of Damascus steel, beyond the patterning, are flexibility and the ability to stay sharp. AFAIK the "rediscovered" Damascus steel demonstrates both, if properly made, so it should be close enough to the historical prototype.

The knowledge has been lost, but also probably never really existed. The legendary damascus steel had a specific mix of impurities, things other than carbon and iron, but the smiths of the time could not have known of those impurities. They would simply know that iron from certain sources/mines was magically better. When those sources of iron ran dry, damascus steel stopped being a thing. Today it is more of an ornamental pattern than a practical improvement in the blade.

On the opposite side, Japanese swordsmiths worked with very pure iron heavily refined from sources like river sand. It didn't have many impurities, resulting in rather soft steel. That in turn mandated all the folding that Japanese swords are famous for. Damascus steel was good ingredients turned into great steel. Japanese steel was mediocre ingredients turned into good swords.

Actually, the iron they were able to refine wasn't terrifically pure because of the source they had for it, sand. The folding wouldn't have done anything to make pure iron into a better blade.

What all that folding did do, however, is ensure that all the impurities in the metal were evenly distributed throughout the blade, thus allowing lower quality metal to be used to make high quality blades.

I think we now understand much of the legend of the original damascus steel to have come from trace amounts of vanadium in the ore.

I'm not an expert, but that sounds right (matches what I've read in papers).

This page has interesting info. https://www.tms.org/pubs/journals/JOM/9809/Verhoeven-9809.ht...

It seems likely 3 factors were important in creating "real" Damascus steel. The key one being the mixture of elements in the raw ore that specifically came from the mines in a specific region of southern India, and once that ore ran out the "secret was lost". There's also the knowledge of the forging process - namely the temperatures, heat treatment processes used, and what organics (aka carbon) got mixed in.

“Damascus steel” can mean different things, but is mostly an aesthetic at this point. In modern times, it is often referred to as ‘pattern welding’.

Not really. The technique is well known and pretty simple. If there are differences between old and modern Damacus steel, it's mostly down to impurities in materials, but you can get all kinds of different results depending on material and technique. Some are vary similar to the original.

Damascus steel, old or new, is kind of shitty for practical purposes when compared to ordinary, good quality tool steel we have now, so it's all about the looks anyway.

Damascus is used colloquially to refer to pattern-welded steel where a maker forge welds a stack assembled from thin strips of steel where a high nickel alloy is alternated with a low nickel alloy. The different steel alloys have similar properties so they form a solid piece but the heterogenous structure is revealed by etching with acid and the alternating strips of high and low nickel alloy make pretty patterns.

Example of damascus steel kitchen knife here.

https://www.surlatable.com/miyabi-kaizen-ii-chefs-knife/2403...

They're considered high-end but still pretty common. That said, Damascus is more of an aesthetic these days.

Yes, you are correct. We know that what is marketed as damascus steel today is not at all the same.

"Damascus steel" today is mostly made for visual effect and the name is used for marketing purposes. I personally think this is ok, since there is no competition with actual damascus steel.

The visual/marketing focus on so-called "Damascus" steel is almost ridiculous:

I own a "Damascus" knife. Like many well-designed modern knives, it uses a core of hard steel in the middle (VG-10 in my case) clad between two layers of soft steel. This is a very good design, enabling one to always have a hard steel for the cutting edge while also having the durability of soft steel from the bulk of the knife matter.

Now a moment's thought shows that the "Damascus" part - which is on the outer cladding layers - has absolutely nothing to do with the cutting edge, and is therefore entirely superfluous from a functionality standpoint :)

Having attended University of Forged in Fire for many years, I am now an overconfident internet authority on knife making. What you are referring to is call "san mai", not Damascus.

https://en.wikipedia.org/wiki/San_mai

I think you're both right - yes, the harder-steel-in-the-middle is what gets called 'san mai' (though smiths all over the world have forge-welded harder steel to softer iron for tools and in knives for a long time), and the parent was describing a knife with decorative 'damascus' patterns on the outer layers of a harder steel center. I have a similar Shun [1] I got from Williams-Sonoma years ago, which slices onions as usual, but looks good doing it.

1: https://shun.kaiusa.com/

Odd. My son's steel ends up with 100-200 layers of alternating steel. Not 3?

AFAICT the Damascus steel in this example is the decorative soft steel on the outside with a thin piece of brittle hardened steel on the inside to keep the edge sharp

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