Steel has considerable strength and durability. And its flexibility means that that there at least as many design options as with any other material. Variations in the type of steel add to its potential uses.
The basic and popular type of steel, also known as plain carbon steel. Mild steel has a fair amount of flexibility, not cracking when bent, yet it is very strong. Its strength is more than sufficient for withstanding almost all natural elements, and can span several meters without reinforcement. It is also great for welding.
This is normal good quality steel used to reinforce concrete or masonry. Steel increases the tensile strength of the materials, which already possess good compressive strength. In other words, the steel inside the concrete prevents an unsupported slab from breaking under stress. There are countless types of steel used for different re-enforcement situations. Many building would not be possible without steel reinforced concrete.
This is steel that has been made rust proof with the addition of nickel and chromium. It is not completely immune to rust as salt in water and air will cause corrosion, as will direct contact with other metals. Yet it is still an extremely long lasting and durable metal. Modern techniques can be used to paint stainless steel, something that was previously quite difficult; though many like to keep its natural matt silver appearance. It is popular for everything from cutlery to building projects.
Fences, internal or external, are often made from steel. Almost any shape and colour is possible.
Law requires all permanent pools to be fenced. This is an important safety issue. But the design of the fence is quite flexible. Often the garden can look better for the addition of a suitable fence.