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Letter 28031
Embrittlement after yellow passivation
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We are using Zinc plating (yellow passivation) on CRS ( EDD grade)
sheet used as drawn can cans. We noticed an embrittlement of the
steel after plating. This embrittlement was so bad that when two such
products were hit against each other they developed longitudinal
cracks (cracks along the axis of the can). Could you pl suggest a
cause and a possible remedy.
Thanks,
Arun Bhardwaj
automotive component manufacturing - Gurgaon, Hryana, India
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Mr Bhardwaj
Please follow this procedure
Plate Zinc
Rinse x 2 times
Nitric acid 1 percent dip. 10 secs.
Dry.
De embrittle at 220 Centigrade for 120 minutes. Check and establish
time.
Cool in air naturally.
Activate in 1 % Nitric. After component is cool.
Chromate as needed.
This is the procedure to eliminate Hydrogen Embrittlement after
plating. Before Passivation. Good Luck.
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