Metal finishing Q&As since 1989

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ElectroGalvanized steel caused salt spray problem

March 30, 2009

I have my Electro Galvanized steel which gone through the pre-treatment by zinc phosphating process and powder coating with >80 micron. But, finally it still failed the salt spray within 24 hours. After analyzed, I found that the e.g., steel will scratch and produce some powder form of e.g., while bending process. the powder form form of e.g., then will compressed and stick along the bending line and we can saw the black dot. After powder coating process, the compressed e.g., seem to became a small volcano when viewing through a microscope and the hole in center cover with very thin of powder and can be easily remove. Is there any idea to overcome this problem?

Rec GT
employee - Ipoh, Perak, Malaysia