The waterproof skin on the outside of some of them may also be of copper sheet, tarred felt or steel.
Low alloy tool steel
In 19th century, wagons and carriages had tires made of iron or steel which did no harm to the wearing surface.
Magnets attract the metals nickel and cobalt as well as iron and steel, but they have no effect on most other materials.
The tongue is not steel, yet it cuts. —— Aesop
"The basic corrosion resistance of ductile is equivalent to that of steel, and in some cases slightly better."
"Carbon steel has high and low temperature strength, is very tough and has excellent fatigue strength."
"Because harden steel is difficult to machine. But when anneal, it can be easily machined. "
"NIBCO Ductile Iron Valves are an excellent, readily available alternative for cast steel valves."