How can you "measure" a type of steel's atmospheric corrosion resistance?

Question

Some types of steel are said to be "weathering" steels, meaning they are resistant to certain types of corrosion. How is that measured? I mean, how does someone know that one type of steel is more or less corrosion resistant than another? Is there some standard unit measurement?

Any info on this issue would be well appreciated.

Many thanks!

Shant

Answer 1

by long testing, for example see this,..

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http://www.nzsteel.co.nz/index.cfm?objec...

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