As someone who knows some metallurgy, the current Stone -> Iron -> Steel progression doesn't really make much sense.
In terms of Iron, the important part is the carbon content.
<.8% carbon = Wrought Iron (https://en.wikipedia.org/wiki/Wrought_iron)
between .08% carbon and 2.14% carbon = Steel (https://en.wikipedia.org/wiki/Steel)
>2.14% carbon = Cast Iron (https://en.wikipedia.org/wiki/Cast_iron)
Wrought Iron is soft, Steel is the good stuff, and Cast iron is too hard/brittle.
I assume that the "forge" in-game acts as a bloomery (https://en.wikipedia.org/wiki/Bloomery), which means that our forge + anvil made "forged Iron" is actually wrought Iron. We then use a crucible (https://en.wikipedia.org/wiki/Crucible_steel) to make steel. In general, well made steel is better than Wrought Iron. It's harder, yet doesn't shatter like cast iron, allowing it to keep a edge better.
The problem I have with all of this is that there is plenty of iron/steel in the environment already. Most combustion engines are full of quality steel, and cars are are even more full of it. Even poor quality modern tools have a decent amount of steel. It just doesn't make sense to try to mine Iron ore in any way when there is so much steel available in the environment. It seems that the Devs have tried to push towards mining of resources by making higher quality tools require large amounts of both "tool parts" and steel, which doesn't' make sense. A better pick doesn't take more resources to make, just higher quality ones.
I believe that the hard part of crafting a high quality tool should be creating the high quality steel, by carefully controlling the carbon % and the % of other trace elements, and not just getting "more" iron. I know that game-play takes precedent over realism. If I had my way, Steel would come in qualities, and a craftable/consumable crucibles would be used in a forge to combine scrap iron/iron ore +sand/clay/grass/bones/etc. into various quality steels, which would be used in steel tools.
In terms of Iron, the important part is the carbon content.
<.8% carbon = Wrought Iron (https://en.wikipedia.org/wiki/Wrought_iron)
between .08% carbon and 2.14% carbon = Steel (https://en.wikipedia.org/wiki/Steel)
>2.14% carbon = Cast Iron (https://en.wikipedia.org/wiki/Cast_iron)
Wrought Iron is soft, Steel is the good stuff, and Cast iron is too hard/brittle.
I assume that the "forge" in-game acts as a bloomery (https://en.wikipedia.org/wiki/Bloomery), which means that our forge + anvil made "forged Iron" is actually wrought Iron. We then use a crucible (https://en.wikipedia.org/wiki/Crucible_steel) to make steel. In general, well made steel is better than Wrought Iron. It's harder, yet doesn't shatter like cast iron, allowing it to keep a edge better.
The problem I have with all of this is that there is plenty of iron/steel in the environment already. Most combustion engines are full of quality steel, and cars are are even more full of it. Even poor quality modern tools have a decent amount of steel. It just doesn't make sense to try to mine Iron ore in any way when there is so much steel available in the environment. It seems that the Devs have tried to push towards mining of resources by making higher quality tools require large amounts of both "tool parts" and steel, which doesn't' make sense. A better pick doesn't take more resources to make, just higher quality ones.
I believe that the hard part of crafting a high quality tool should be creating the high quality steel, by carefully controlling the carbon % and the % of other trace elements, and not just getting "more" iron. I know that game-play takes precedent over realism. If I had my way, Steel would come in qualities, and a craftable/consumable crucibles would be used in a forge to combine scrap iron/iron ore +sand/clay/grass/bones/etc. into various quality steels, which would be used in steel tools.