Civil Engineering - Building Materials - Discussion

Rail and crossing: Carbon steel.
Ball bearing: Chrome steel.
Magnet: Ferritic stainless steel.
Axle and spring: Vandium steel.

Chromium-vanadium steel (symbol Cr-V or CrV; 6000-series SAE steel grades) is a group of steel alloys incorporating carbon (0.50%) , manganese (0.70-0. 90%) , silicon (0.30%) , chromium (0.80-1. 10%) , and vanadium (0.18%). Some forms can be used as high-speed steel. Chromium and vanadium both make the steel more hardenable.

Thank you for description.

Thanks for it, and also tell me about that how much % of carbon are use on it? Is this steel are free from carbon?

The considerable increase of strength in steel containing small amounts of vanadium, Vanadium forms stable nitrides and carbides, resulting in a significant increase in the strength of the steel. Vanadium steel is used in axles, bicycle frames, crankshafts, gears, and other critical components.