There are so many things wrong with your post that I feel forced with comment.
1. Best trade of cost of ingredients to value of the resutls is Steel Plate Armor. UESP lists value added ratio for every smithing item, and Steel Plate Armor comes on top with 5.9 rating. It's so good, you will make money if you buy raw materials (iron, steel, corundum, leather strips) from the blacksmith, make the armor, improve it, and sell it back to the same blacksmith. This means getting smithing from 50 to 100 is relatively quick, painless and totally free if you have Advanced Armor Perk.
2. As others have already mentioned, best use of iron ores is transmuting them and using silver or gold to make jewelry.
3. Improving is very very good for experience gain. Experience gained is roughly proportional to the square root of value created when you make a new item, or value added when you improve an item. For example, improving a Daedric Armor to Legendary costs only 1 Ebony ingot, but it will give you as much experience as making a brand new Daedric Armor.
There are so many things wrong with your post that I feel forced with comment.
1: Dwarven Igots can be gotten in vast quantities for free. The ruins under Markarth you can scavange nearly 400 igots, a couple hundred more can be found in the museum if you don't mind steeling. In essence you can't count the cost of the dwarven igot in the real cost ratio because it can be acquired in
vast quanities for free relatively quickly. So the real cost ratio on Dwarven armor is 13.3 which shattered steel plate completely. And remember the cost ratios presume your buying and selling at base values which isn't always the case.
But the real champion is the Dwarven Bow costing two dwarven igots and one iron igot, after coming out of a ruin with a couple hundred free dwarven igots the cost ratio is
38.6.2: It can take quite sometime and a lot of effort to gather all the necessary gems in order to make that much jewlery. It also requires A LOT of time casting transmutation inorder to make that iron into gold or silver.
3: Tempering isn't going to be more effective then making new items until your smithing gets to a fairly respectable level. In which case dwarven once again becomes a true champion as you can get hundreds of Igots for free.