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Zinc plating case hardened steel

I need to zinc plate case hardened steel, but the hydrochloric pickle won't remove the scale.
How do I get it off?

Chris Burgess
Jobbing shop owner - Brisbane, Queensland, Australia
May 12, 2010

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First of three simultaneous responses --

Dear Chris Burgess,
Removal of Heat treatment scales in HCl is very difficult; if the part are very big, better you do the blasting or if the parts are tiny/very small do the vibro polishing with suitable media, keeping long time in Acid bath is not advisable, hydrogen will penetrate inside, after removal of scales in vibro or blasting also use the acid inhibitor (not fume inhibitor) in the acid bath. if you are select the blasting, please reconfirm the case depth after plating.

Kannan Booopathi
- Salem, Tamil Nadu, India
May 14, 2010

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Second of three simultaneous responses -- May 15, 2010

Dear Chris,

I think just Hydrochloric Acid pickling is not strong enough to remove the stubborn scale.

In my country, I use to offer Degreasing,Anodic Cleaning +Descaler Agent(1), Acid Pickling + Pickling accelerator additive,Anodic Cleaning+Descaler Agent(2)+Acid dip then go for Zinc plating(either Acid or alkaline zinc/zincate).
Or another option:
Degreasing+Anodic Cleaning(1),Cathodic Acid Pickling+Anodic Cleaning+Acid Dip, then go for Zinc plating.

Hope that you can try and see what will happen.

Good luck.

Best regards,

Tony Chandra
- Jakarta, Indonesia

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Third of three simultaneous responses --

No stronger acids please! Use a shot blast or vibro method to remove the scale.

Khozem Vahaanwala
Saify Ind

Bengaluru, Karnataka, India

May 16, 2010

I am interested to learn about nickel plating process on hardened steel parts. Thanks in advance who is able to let me know.

Pedro Pinho
plating shop employee - portugal
September 23, 2010