On my realm Titanium is going for 40g for a single ore. So I thought about trying to buy up ore off the ah so I can change it to Titansteel bars since a stack of 20 Titansteel bars was going for 4500g. I wondered if it would be cheaper to buy ore off the AH to smelt into Titansteel bars and make a large profit so I did the math.
It takes two Titanium ores to equal one Titanium bar. It takes three Titanium bars to equal one Titansteel bar, not counting the Nethers that you need.
So for a stack of 20 Titanium bars you need forty ores.
Now on my realm a single Titanium ore was going for 40g at the lowest price. That meant that a stack of 20 ores you'd need 800g. Not too bad so far. So that means for two stacks of ores you'd need 1600g. Okay, that's a bit steep. At this is at the lowest price. I believe the highest was roughly 65g for a single ore.
So for a stack of twenty Titansteel bars you'd need sixty titanium bars. Out of a stack of twenty Titanium bars you can get six Titansteel bars with two Titanium bars left over from each stack so that you'd need sixty bars to get an even twenty Titansteel bars.
So sixty titanium bars means 120 ores total. That's six stacks of twenty or 4800g. That's a loss of 300g to buy all the ore necessary to make a full stack of Titansteel bars. So no, buying the ore would not be a profit.
Also you can only make a Titansteel bar once every twenty hours so that's 400 hours worth of work.