It means just what it sounds like -- something is really hard.
iron and copper are hard materials .
Cast iron
Yes they can. Iron doors are very hard but not hard enough.....
its like really really hard
Tetsu or Kurogane is iron.
its not hard enough
Iron
Yes.
No, iron pyrite, unlike iron, is not malleable at all. It is a hard, inflexible rock.
Ferrous means pertaining to iron.
- Iron is very cheap- Iron is easily processed
Iron that has some carbon is cooled very rapidly from about 1300 degrees F. to close to room temperature . The carbon atoms get in the way of the iron atoms as they form a lattice work in the cooling steel. that makes the steel very hard but very brittle. The the next step is to reheat the iron to about 440 degrees F. that way you get a reasonably hard iron that won't break when you need to use it.