RE:Vanadium in Steel and fall in iron ore, steel and coal priceRiverrock,
As far as I can tell, ASTM A36 steel did not have vanadium in it. So subsequent to ~2000 when ASTM A992 steel came into much wider use, much more vanadium would have been used in structural steel.
I'm still looking into ASTM A615 steel for concrete reinforcing. I don't know if there have been any chemical composition changes.