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        | Title: | COATING, OXIDE, BLACK, FOR FERROUS METALS |  
        | Number: | MIL-C-13924 |  
        | Revision: | C |  
        | Scope: | This specification covers black oxide coatings applied to ferrous metals (wrought iron, carbon, low alloy, and corrosion resistant steels).  Black oxide coatings, with or without a supplementary preservative treatment, may be used where a black surface is required.  Only very limited corrosion protection, under mildly corrosive conditions, is obtained as a result of black oxide coating.  Black coatings are included in this specification with limitations as noted. |  
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              | Classification: |  |  
                | Classes              | Black oxide coatings covered by this specification shall be of the following classes as specified. |  |  
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              | Details | Description | Can Do |  
                | Class 1 | Alkaline oxidizing process (for wrought iron, cast and malleable irons, plain carbon, and low alloy steels) | Yes |  
                | Class 3 | Fused salts oxidizing process (for corrosion resistant steel alloys which are tempered at 900F or higher | No |  
                | Class 4 | Alkaline oxidizing process (for 300 series corrosion resistant steel alloy only) | Yes |  |  
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