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Corrosion prevention is the use of various methods to protect metal objects that are prone to rusting, in order to extend their service life. Generally, physical corrosion prevention, chemical corrosion prevention, electrochemical corrosion prevention, and other methods are used.

The anti-corrosion level is classified into the following five levels according to indoor and outdoor:

It can be seen that WF1 and F1 are respectively of the outdoor moderate corrosion protection type and the indoor moderate corrosion protection type. These two corrosion protection levels are applicable to different environmental conditions and are not comparable.
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