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Material (bolts) after Zinc electroplating , how will it look (color)

Today we have a problem at site related to bolts . As per standard we have to use M30 size bolts ( coated with Galvanized / Zinc electroplating) . Our store persons are not technically sound . They have issued as per code shown . When it reaches to site . Our lead bosses are asking wether these bolts are as per code .Our company code says : hot -dip galvanized or zinc electroplating bolts are to be use . We are not getting proper documents to identify these bolts are correct or not ?

So , now my question is as a lay men how he can identify is this bolt is correct or not ?

After zinc electroplating is there change in colour ? if change how it look like ?

thanks

Kengam
- Jamnagar, Gujarat
2007

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2007

Dear kengam,
I believe now-a-days even a lay man is a bit smart.I will try to explain how to differentiate a zinc plated and non plated bolt.
1.If you find the bolt is partially rusty, it may be plated but without quality
2.If the bolt is fully rusty,it may be un plated or very badly plated.
3.Plated bolts usually look blueish white/iridescent yellow/olive/or(Indian military)-green-Different colour indicates different life span against rust and in some cases identify the usage of application.
Hope I am not confusing you.
And finally- JamNagar is a city of around 10 sq.Km area.Have one Industrial Zone-Have around 25 Zinc platers around.Take a day off from your office and visit one such plater.Request him to show an un plated bolt and a plated one.Also request him to show different colour "passivated" ones.Take 1-2 pieces as samples and give it your store person.Inform your boss about this.U will save a holiday.
Regards,

T.K. Mohan
plating process supplier - Mumbai, India