Ah yes MrRazot, the steel trade is one that is popular and although demand is high so is supply.
I made my money by mining gold, smelting was significantly easier, one gold ore sells for 200gp and one gold bar sells for 500gp, a gold ring however, sells for only 150gp (this is because people like crafting their own gold rings). Each trip I could carry about 20 gold bars (estimate) which was 10,000gp each trip. I would mine ore, run to the bank (this was the desert mining site so a bank was quite close), with a rune pickaxe (which I couldn't wield but could mine with) and again, very little people in the gold selling trade, a trip would take about 6 minutes, not including smelting. Which means, in 40 minutes, I would of made 60,000gp (roughly). It was a very good trade, I would sell all my gold bars at the GE for minimum price (sell them for minimum price and they are always instantly sold). minimum price was 450gp.