I was just idly reading through some wikipedia entries on early smelting techniques, and saw an article on the refining of pig iron.
M thought was that if you can accidently 'burn off' carbon in steel by taking it above welding temperature (I have 'killed' the hardenability of some knife steels by getting them too hot), could you not hold mild steel at that heat for a predescribed time at a temperature above welding heat, thus making a 'wrought iron' ish material.
I am pretty confident I am wrong, but It was puzzling me, so I thought I would put it before y'all.
Alfie