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-EresFAMAK 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.

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 Brewingtonplating 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.

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