It all depends on*************
Seriously, if you were using oxy/acetylene, you could well have been increasing the carbon content.
Adding carbon to iron and then mild steel to make tool steel is quite normal for your neck of the woods.
I'm refering to the sword makers of Shotley Bridge who made swords so well that gentleman of the day could wind a sword in their top hat.
It all started in 1691 and since then, things have got- well, less interesting!