It's interesting how difficult it is to actually make large quantities of quality steel.

On the surface it seems like an easy process to make steel, but it required hundreds of years of gradual technological progress to get to the point where large quantities of consistently decent steel could be manufactured. So many independent inventions and scientific discoveries where required before we could make steel. It's really a material that's taken for granted.

It would be interesting to make a sort of real life tech tree of the inventions required to get to modern steel.