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Anti corrosion refers to the use of various methods to protect metal items that are prone to corrosion, in order to extend their service life. Usually, physical, chemical, and electrochemical methods are used for corrosion prevention.

The anti-corrosion level is classified into the following five levels based on indoor and outdoor conditions:

It can be seen that WF1 and F1 are outdoor anti-corrosion and indoor anti-corrosion, respectively. The environmental conditions applicable to these two anti-corrosion grades are not the same, and they are not comparable.
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