I've heard that the reason societies switched from bronze to iron was not because iron was a better material, but because it was more available.
However, the Iliad (I believe?) makes mention of an ingot of iron being presented as a prize, so apparently it was seen as quite valuable. Why would this be the case if it was so much more common than copper or tin?
I've also heard that bronze age societies didn't produce iron weapons because iron has a much higher melting point, and they didn't have furnaces hot enough. But bronze age cultures did make iron artifacts throughout the bronze age, so that can't be right, can it?
Some people counter the "iron is superior to bronze" idea (which I think is widely believed by non-historians) by saying that in fact bronze is superior to iron. It has a lower melting point, it can be cast, it's resistant to corrosion, and I would imagine that it's easier to control for its hardness/flexibility (since copper is soft, and bronze becomes hard by adding tin).
If this is true, why did societies make the switch at all? Is it because the collapse of trade networks necessitated the switch to local metals? Those trade networks were eventually reestablished - did that have an impact on the use and manufacture of bronze goods in later eras?
Sorry, this is a lot of questions. But I would appreciate any insights about any one of them!
While bronze has certain material advantages over iron, it's by no means the case that bronze is always better than iron. For many purposes well-worked iron is as useful as bronze, or at least not significantly worse. Bronze does tend towards a higher hardness than wrought iron, and absent all other factors is frequently better than wrought iron, though not necessarily by much.
However, there are a variety of different ways of working iron, and to produce iron you need access only to the abundant iron (6.3% of the Earth's crust, albeit much of it comparatively hard to access compared to the other numbers, you still end up with a whole lot more iron) instead of both the somewhat common copper (0.0068% of the Earth's crust) and the rather rare tin (0.00022% of the Earth's crust). Beyond that, Tin and Copper are rarely found close together, which further complicates matters.
Early ironworking wasn't suited to produce the kind of variety of tools that contemporary bronzeworking was capable of. In particular, once people started to experient with iron in the middle bronze age, the carbon content was not like what it would end up being down the line, frequently resulting in relatively brittle iron. Thus, the kind of iron tools that were produced during the bronze age were simply less varied than what they were capable of producing with bronze.
However, iron's abundance encouraged perfection of iron-working, and as states grew from small kingdoms into empires, abundance became even more important than perfection. It's simply better to outfit a thousand men with good weaponry than it is to outfit a hundred with great weaponry. It would never have been feasible to outfit the Roman Legions with bronze, the costs would have been far too steep, if there even was enough bronze available for the Romans to get their hands on.
And when it comes to civilian applications, the material differences rarely mattered unless iron's much greater tendency to corrode quickly comes into question, and in fact that's where bronze stuck around as a staple deep into the iron age and beyond.
hi! hopefully someone can comment on each of your points, but fyi, you can find discussion on some of them in this section of the FAQ