Oh, and as for 'turning cat iron into wrought iron'

If you get (by burning or slagging) all the impurities out, old type cast iron is pretty weak. Modern 'spheroidal' stuff is a different game.

Wrought iron was made from billets of fairly impure iron, by belting it to squeeze all the remaining sludgy slag out***. Carbon was in the sludge too - so some steel was formed. The grain structure is formed as a consequence of this process - if you belt the billet enough it lengthens and narrows so you fold it and weld it and belt it until you are tired of doing so. You get 'ropes' of iron surrounded by steel. If you have heard of 'pattern welding' - swords which are made of several pieces of metal shaped and welded like a piece of braided belt, then you are on a similar wavelength.


*** This was the case until such processes as the Bessemer Converter came along. It achieved higher temperatures, thus more completely melting the metal and floating the slag to the top, where the oxygen blast burned it out, leaving fairly pure molten iron. The older lower temperature processes tended to give a sludge of lumps of iron full of sulphur, phosphorus etc mixed in with semi molten slag - thus you literally had to 'beat the shit out of it'. :-)