Steel stock storage / racking

Sheet material we store on edge to save space. We use a lot of 3mm thick 3000x1250 sheets and lift them out with a plate grab on the crane. Simple pressed channel base with RHS uprights. Larger deliveries of sheet for specific orders tend to come off the delivery wagon and go straight to the guillotine or brake.
Large sections and bars are on a rack similar to that Wyn described - heaviest at the bottom. The arms get shorter the higher they are to make it more stable. These are lifted on/off by forklift.
Smaller bars are in a pigeon hole rack and are simply slid out from one end by hand.

We inherited a load of raw material racking from a company we bought out last year. We were never going to need it all so I offered to buy some. There were also a couple of nice welding benches and some pallet racking. Next thing I knew was the scrap man was in taking it all away What a waste, but typical of some of our management.

Regarding corrosion, all our raw material comes in oiled and doesn't usually hang around long enough to get too rusty. Some of the heavier structural sections are stored outside for H&S reasons and as such do rust, but we have our own shot-blasting facility and accept the additional process will be required - it's cheaper than putting up another building.