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Zinc phosphatizing and the embrittlement problem

We are in the business of manufacturing disc spring made out of spring steel. As surface coating we do Zinc phosphating on the spring. we would like to know weather hydrogen embrittlement is required for this process. If so, please give us the details for the hydrogen embrittlement process to be carried out.

Haridas Raghavan Nair
- Thane, Maharashtra, India
 

Hydrogen embrittlement takes place because before zinc plating when spring are put for pickling, hydrogen from acid gets entrapped on surface and zinc plating thus chances of failure of component increases. To avoid these failure go for least amount of time in pickling, moreover go for acid baths in zinc plating maintaining ph b/w 4 to 6 , don't go for cyanide baths, & in zinc plating. If it is possible go for drum/barrel rather hanging components in tanks.

Vikas Kaushal
- Chandigarh India
 

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We encounter no problems by using springs made of hot dip galvanised steel wire and we also apply zinc-phosphating. Perhaps this is an alternative. In the end, it gives a better overall corrosion protection.

Best regards,

Peter Piessens
- Bertem, Belgium