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topic 11224

Two grams of hexavalent chromium = ? kilograms of zinc plated fasteners


This question is about European Commissions directive on End of Life Vehicles. About this 2 grams of hexavalent chromium allowed per car, how many kilograms of zinc plated fasteners will contain 2 grams of hexavalent chromium on their passivation?

Elif Kiray-Eres
FAMAK A.S. - Istanbul, Turkey


The easiest way out of this problem is to get a handful of the fasteners and ask a local lab to test them to ISO 3613 [link by ed. to spec at TechStreet] for hexavalent chrome concentration per fastener.

Martin Trigg-Hogarth
Martin Trigg-Hogarth
surface treatment shop - Stroud, Glos, England


Use the surface area of a part to calculate the approximate weight of hexchrome in a part. Then find the number of parts in a kilogram using a parts counting scale. Use this information to compute your answer. Alternatively, compute the maximum chromate allowable per part to meet the regulation. Then analyze the chromate solution after a few batches. If less chromate is removed from the bath then is needed to meet the weight requirement, you can be assured the regulation is met since naturally dragout is a component of solution depletion.

Michael Brewington
plating shop - Salisbury, Maryland, USA


Clear to Blue passivation : 5 - 10 mgs/ m2

Yellow passivation : 50 - 100 mgs / m2

Black chromate : 200 - 300 mgs / m2

Olive Chromate : > 500 mgs / m2.

Now calculate the surface area of the fasteners and passivation you are using and you have an appx figure to work with.

Khozem Vahaanwala
Khozem Vahaanwala
Saify Ind supporting advertiser
Bangalore, Karnataka, India

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