Letter 40068

How to judge whether plating passes B117 12 hours or 96 hours?  

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Many times I saw clear zinc plating can pass B-117 [link is to spec at TechStreet] 12 hours and yellow zinc plating can pass B117 96 hours. According to B-633 [link is to spec at TechStreet], it does.

but I have question, what does B117 12 hours or B117 96 hours mean since B117 is just a test method and doesn't specify the rusting degree (the rusting degree specified by D610 [link is to spec at TechStreet] ) ?
I just want to know at how much rust area is allowed to pass B117 12 hours test ? Can you guys please tell me?

thanks,

John
Nabob - ShenZhen, China

No rust is permitted.

Corrosion resistance requirements are given in ASTM B633 "Standard Specification for Electrodeposited Coatings of Zinc on Iron and Steel." After salt spray, Types II & III coated specimens "shall show neither corrosion products of zinc nor basis metal...visible to the unaided eye at normal reading distance" except white corrosion at edges.

Ken Vlach - Goleta, California