I read about so colled 'shunts'. Steelplates you put into the earth to protect your construction site for water. It is also partial used on a river side.

Those things are not painted and google told me that you can calculate how much is oxidized in a year.

I would really love to know how a shipping container is so much more fragile.

Perhaps it is not that relevant but in masses it makes a relevant amount of money. Like steel container 20 years and with color 25 years and that makes it just better.