Bronze vs. Iron vs. Steel

[Brother MacLaren]

Bronze is also about 5-10% denser than iron, so combined with the lesser stiffness (requiring thicker cross-sections), iron might have also been preferred just for lightness.

Really? I thought 2E modeled bronze plate mail as lighter than conventional plate mail, which made an interesting tradeoff for its lesser AC. But I respect your knowledge.
As an aside, has anybody ever thought the following about D&D metals?
Adamantine = titanium (very hard)
Mithril = aluminum (strong as steel but lighter)

And, with regard to the ancient swords, there are a bunch in Topkapi Palace that are allegedly 1300 years old and in great shape - including the sword of Mohammed. I wonder about the authenticity of those items, but I suppose anything can last if it is well preserved (and the climate in Turkey is drier than that which produced the corroded Viking longswords I've seen elsewhere).

 

[John Morrow]

Some adjoining ancient peoples - the Hittites, for example - had little access to bronze, but did mess around with iron.

Well, they also had to figure out how to make a fire hot enough to smelt iron reliably. A 'normally aspirated' wood fire won't get hot enough.

I'll defer to your points on early Mesopotamia because my knowledge of the period is most extensive conserning the Late Bronze Age (LBA) in and around the Mediterranean. I do know that getting tin was a real problem for the Mycenaeans, Egyptians, and Hittites because they had to get it from the East. Lapis Lazuli was another big import from the same areas.

But it wasn't until the easily accessible tin and copper deposits ran out that the bronze age civilizations started to work with iron. So during its heyday, bronze would be cheaper than iron, at least in those civilizations that control the tin and copper mines. Then eventually declining supply leads to exploitation of different metals, which are initially harder to exploit but are actually available in much greater quantities.

Well, I'm not sure that iron is that much more difficult to extract or process than both copper and tin so I'm not sure that it would be more expensive to anyone with access to the ore and the technology to make a hot enough fire to smelt it. Are there any other factors, other than the technology to make fires hot enough to smelt iron (involving a bellows or fuels other than wood) that make iron more expensive to exploit or use?

 

[Krieg]

It's got a decent grounding in history, so the different styles are quite easy to imagine (and you could also find appropriate illustrations easily enough).

...albeit a very one sided and less than accurate portrayal of history.

The current "Muslims good - Christians bad" portrayal of the Crusades is every bit as inaccurate and politically/theologically motivated as the previous "Christians good - Muslims bad" western viewpoint.

The reality (as with most things) is of course somewhere in the middle and far more complex than mere caricactures.

....of course down that path lies the certainty of a locked thread.

 

[Galethorn]

One note about titanium: The numbers it's always compared against as a 'super metal' are for mild steel. In terms of blades, titanium just can't get hard enough to hold a proper edge. Also, being half as dense as steel, you have to make a blade twice as wide to even approach the same cutting performance...

Oh, and titanium's 'strength' when refering to submarine hulls or airplain parts, it by weight; steel is just as tough by volume.

Now for a short dissertation on blades and cutting...
The thinner a blade is (looking edge-on), the better it cuts, because it doesn't have to displace as much flesh/whatever when it impacts, meaning that it can cut deeper. Now, this is balanced by the fact that a sword's cutting ability is heavily dependent on the momentum (combination of speed and mass) that it has when it hits, in that it cuts by shearing material apart on the axis of the cutting edge, like how the prow of a boat goes through water. The faster the blade is going, the better a job it does of shearing, and the more mass it has, the longer it maintains that speed after impact, while cutting into the target.

So, that's why you want cutting blades (other than the katana, which I'll explain in a bit) to be as thin as possible in relation to their mass. This means that you want a sword that's a balance of mass (for momentum), thinness/edge geometry (for shearing capability), lightness (so you can actually get it up to speed), and balance (so you can move it where you want it).

Therefore, a titanium sword, to cut as well as a steel sword, would have to be twice as wide at the same thickness, but it would only have half the typical rockwell hardness of a steel sword...at the low end of the historical range (pure titanium: average of about 24 HRC; most medieval cutting swords: 48+ HRC at the cutting edge)...so, it would cut fairly well the first couple of times, but it would quickly become dull. Not good for a sword.

Now for the bit about katanas (yes, I know in Japanese, the correct plural of katana is katana, but here in America, we speak American! )
Ok, so I implied that the best cutting blades end up being very wide and thin, whereas katanas are thick and narrow. The difference is in the actual shape of the edge. You see, a european sword has the main bevels of the blade (the parts that angle towards the edge), then it has the edge-bevels (the actual sharp part), which come together to a much more obtuse angle than the blade would if you extended the main bevels until they met. Well, that obtuse angle is the part that does all of the cutting, and it's definately sharp enough to cut...so, imagine what would happen if the whole blade was at something like that angle? It would cut very well, because of the added momentum from the added mass.

*** *** *** ***

Ok, now, back to the point of the thread...

So far, I have to agree with the general concensus: Good steel is harder and tougher than the best bronze, but even the worst bronze is as hard--and tougher--than the worst 'iron'...

What hasn't been discussed is the specifics of what 'iron' (in the same context as steel or bronze) is.

When iron was smelted with charcoal, the end result was three different alloys in varying amounts: cast iron (so much carbon that it shatters at the drop of a hat, but its melting point is low enough to cast things with it; can't be forged), steel (medium carbon content, not much slag; pretty easy to forge), and wrought iron (low carbon, lots of slag, very tough but quite soft and almost impossible to harden; really easy to forge).

Cast iron was never really used for weapons or armor, from what I've read, supported by common sense.

Steel was obviously used for blades because it was easy to work compared with bronze, it could be hardened, and so on. Early steel wasn't the most common/easy to separate of the components in the bloom (the big chunk of metal that results from smelting), and it had a lot of variation in carbon content, leading to making pattern-welded blades in europe. Part of the reason the japanese folded blades (other than spreading out contaminates so they wouldn't make a weak point) was to homogenize the carbon content of the steel, so there wouldn't be soft and tough spots mingled with hard and brittle spots.

Wrought iron was the easiest component to extract from the bloom, and it's very easy to forge. Because of the 'trace' amounts of slag in it, wrought iron rivals modern mild steel in toughness, surpasses it greatly in rust-resistance, and is many, many times easier to forge-weld (i.e. get two pieces really hot, then hammer them together to make them bond). Because of this, a lot of tools (and some weapons) were made with wrought-iron cores and high-carbon steel edges, all the way up to the end of the 19th century, primarily evidenced by wood-cutting axes. As well, most armor was made of wrought iron up until the advent of plate armor (which had a lot to do with the industrial-scale, waterwheel-powered iron-smelting factories in the late middle ages).

Also, the business ends of weapons other than swords and axes were often made entirely of wrought iron up until the late middle ages.



Ok, that came out a lot longer than I expected, so there may be some minor errors...I think I'll stop now while I'm ahead.

 

[Umbran]

Has anyone, perhaps, thought of having ancient weapons be of less-impressive metals, like bronze or iron? What did you do to mechanically model the older weapons, if so?

Yes, I thought about it. I left all metallurgical discussions aside and came to a much mroe useful conclusion - unless those older weapons somehow mande the story better, I wasn't going to bother with them.

Generally speaking, if you make those ancient weapons inferior, the PCs will just leave 'em by the wayside, and they won't enter the story at all. Unless you put the PCs in a position where those old weapons were the only ones available, there'd be little point in presenting them. At best they'd be of value to historical collectors, and thus become mechanically equivalent to jewelry or artwork as loot.

 

[tarchon]

I don't think that's true at all. Before the Naue Type II came into common use, they find blades that they call "rapiers" because they have long narrow pointed blades clearly for thrusting. The Mycenaean "rapiers" didn't even have a proper tang and were riveted to the handle. They definitely could not handle hacking. There was also plenty of bronze used for spear points, axes, and arrowheads.

"Rapiers" were a relatively short-lived technology, and some archaeologists are even skeptical that were regularly used as weapons, proposing that the rapiers were more of an exaggerated status-symbol form of the more common dirk. They were definitely more thrusty than slashy, but as thrusting weapons go, they were not particularly advanced, and the form is thought to be a limitation of the casting technology. The whole evolution of the European leaf-bladed sword shows a general trend toward a slashing weapon.
http://www.tf.uni-kiel.de/matwis/amat/def_en/articles/rapier_to_longsax/from_rapier_to_langsax.html
quotes Oakeshott: "Leaf-bladed cut-and-thrust swords were used all over Europe up to about 900 B.C. or later until 'the thrust is almost unused and swords are made just for cutting' [Oakeshott 1960:31]"
It may not be an overwhelming factor, but I'm thinking the basic limitation of stiffness makes bronze an unlikely choice for a thrusting weapon except as a head, like on a spear, or a very short weapon like a dirk.

 

[SWBaxter]

Well, I'm not sure that iron is that much more difficult to extract or process than both copper and tin so I'm not sure that it would be more expensive to anyone with access to the ore and the technology to make a hot enough fire to smelt it.

Since I don't understand how you can divorce access to the ore and the more involved smelting from the extraction and processing expenses, I don't believe I can adequately answer your question.

 

[tarchon]

One note about titanium: The numbers it's always compared against as a 'super metal' are for mild steel. In terms of blades, titanium just can't get hard enough to hold a proper edge. Also, being half as dense as steel, you have to make a blade twice as wide to even approach the same cutting performance...

Oh, and titanium's 'strength' when refering to submarine hulls or airplain parts, it by weight; steel is just as tough by volume.

I agree, titanium is probably a poor choice of sword metal from its hardness, but the density is not so much of an issue. It's pretty easy make something heavier if you need it to be heavier, and I don't know that having a lighter, faster sword is such a huge disadvantage anyway. The cutting edge isn't everything. Ti is used in cutting blades for knives and shears for its corrosion and wear resistance too. I'm not sure what a modern HRC 65 steel would do to a medieval weapon, but I'll bet it would be ugly.

Which also brings me to anther thing I wanted to mention - with the availibility of magic, metallurgy would be very different I suspect, especially with the possibility making wel-controlled low-carbon airless furnaces.

 

[Galethorn]

Well, with the density thing, you basically have less mass for the same cross-section, or else a worse (read: more obtuse) cross-section for the same mass. The lightness would only mean that your weapon would be easier to deflect, in exchange for being a bit less tiring over time...unless you wanted to move the balance closer to the hilt, but that would make it even worse at cutting...

As for an HRC 65 steel against a medieval blade...

Well, let's just say that sword-length pieces of steel like that tend to break when stressed. After all, a katana made with modern steel only gets up to ~62 at the edge (compared with a spine at around 48), and they're well known for chipping when they aren't cutting into something suitably soft, at the right angle. A much better show would be a properly hardened and tempered blade with an edge at about 56-58 against one of the medieval blades in the 40-50 range.


Now, magic-influenced metalurgy would be interesting. If I was a magic-using swordsmith, I would probably try to achieve perfect blade-steel, in that it would be pure martensite (a particular iron-carbon configuration that's optimum for cutting edges) at the edges, and all bainite (a very tough, but still relatively hard configuration that's very difficult to produce consistently) in the core/at the spine (depending on the sword). Oh, and I would arrange the surface oxides to result in a cool color...

 

[S'mon]

Not really. Traditional Tolkien-style fantasy worlds postulate some kind of past golden age when near-perfect godlike beings (such as Tolkien's elves) ruled the world with breathtakingly advanced technology and magic. Then it somehow all went south, and the succeeding dark age where comparitively ignorant successors muck up the world is the modern day setting. That doesn't really match reality all that well, but then again it's not really supposed to.

I was going to say that it matched European reality pretty well from the fall of Rome to at least the Enlightenment circa 1700! - Around 1300 years of our history.
But I think the belief in progress and improvement is a mark of rising civilisations whose power is increasing, while a belief in decline goes along with declining powers. Victorian Britons believed strongly in technological & societal progress, just as most Americans (wth their economic & military global domination) seem to today. Tolkien lived in an era when the British Empire was ending, and I think this influenced the elegiac quality of his and other writers' works. To me, living in a country that ruled over 1/4 the globe a century ago and now barely rules itself, progress and decline both appear natural parts of human history.