Hm, I haven't really been around long enough to have seen previous discussions on metals and other mods, unfortunately. But anyway:
I don't entirely agree with the assertion that bronze is strictly superior to iron. The strength comparisons given above are between a modern tin-bronze, with proportions controlled quite finely, and wrought iron.
In reality, iron used in medieval weapons and armor was at minimum beaten in the presence of atmospheric carbon, hardening the surfaces somewhat. Trace impurities in the iron or unknowingly introduced during forging can certainly cause weakening or embrittlement, but also often strengthen the metal, especially once smiths learn how to work a particular ore. Medieval bronze certainly can be superior to medieval iron, but the reverse can also just as easily be true. The one assertion that my sources did clearly agree on was that it was much easier to make good body armor out of bronze than iron.
While iron stuff may have been case hardened to a limited degree, that would likely be negated very quickly by sharpening. Actually, that's probably why iron scythes were nearly always peened, never ground. Anyway, bronze is definitely easier to make reasonably pure due to the lower melt point, and it's also easy to strictly control the proportions of copper to tin. One historical text I read said that (in ancient Egypt, IIRC) 20% tin was a typical amount for razors, 12-15% or so for small knives, 8-10% for khopeshes and other large blades, 5% for things like plows.
And IMO anyway, it would be far easier to make bronze weapons than iron ones. Bronze can be cast without losing any strength whatsoever. I distinctly remember that the Celts used
horse manure, amusingly enough, as one of the ingredients for their bronze leaf-bladed sword making molds. Anyway, being able to start with a nearly finished casting and then doing all the remaining work at room temperature, definitely gives the bronzesmith a huge advantage. It's much harder to see and feel what you're doing, when you're pounding on something that's glowing cherry red.
IIRC though, iron does have the advantage of being quite a bit springier, while bronze remains quite ductile and malleable even at higher hardnesses (modern bronze alloys usually have stuff added to make them springy), so iron can be used to make make longer weapons (albeit with duller edges). I had forgotten that bit. I think the Koreans were among the first people to transition from short and broad bronze swords to long and slender iron ones (the Three Dynasties era ring-pommel swords). Most other cultures that transitioned from bronze to iron continued to use very similar blade patterns (like the gladius) for awhile longer.
In any event, bronze anvils sound a bit weird...
Not weird at all. Anvils were commonly made of bronze before iron smelting was discovered. I suppose bronze wouldn't work too well for forging steel though, due to the low melting point. Ah, the problems of mixing technology levels.
Several mods have arsenical bronze. I'm not a big fan of the idea, personally. The gap between copper and bronze (or iron, as suggested in the first post) isn't so great that we really need to add a new one-trick metal in the game to fill it. I actually deleted bismuth bronze and therefore also bismuth because they just weren't interesting enough.
I agree about bismuth bronze. But like I said, if I do something like this (or at least get the ideas down on e-paper so I'm ready when the next version comes out), arsenical bronze would mainly exist for cases when you've got copper, but don't have any tin or iron, and aren't expecting a caravan any time soon.
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There have been several massive discussions on this, with no real consensus. For example, bronze is harder and easier to work, but iron's strength to weight ratio is better. Iron weapons can be larger than bronze, a pretty big advantage in battle. Bronze is much stronger and holds a better edge, but shorter.
Yeah, I missed those due to being a newbie (at least to the forum side of things).
Anyway, though, iron actually doesn't have a better strength to weight ratio. Iron has a sp. gravity of 7.8, 10% tin bronze is going to be 8.8. With yield strengths of 520 and 825, iron has a strength ratio of ~67 MPa per g/cm^3, while bronze is ~94. I.e., bronze is only 13% heavier, but 59% stronger.