Summary for zinc plating peel off Discussion
Zinc plating peel off during crimping is described as erratic and random, with the original question asking for root cause and ways to improve adhesion of zinc plating with chromating on stainless steel. Ray Kremer first asked whether a Wood's nickel strike or any strike was being used and what stainless alloy was involved. The poster then clarified the grade as ASTM A36, which Ray pointed out is actually mild steel, not stainless. For the mild-steel case, Ray said poor adhesion is most often caused by inadequate cleaning and suggested checking for a waterbreak-free surface after cleaning and acid dip rinses, and even scrubbing sample parts with a tampico brush and pumice before processing. He also noted that if stainless parts still show poor adhesion despite proper pretreatment, shop contaminants such as silicones could be involved. The discussion leaves open whether the problem is one issue or two, but emphasizes pretreatment and cleaning as the first place to look.
Q. We are facing issue related to flaking/peel off during the crimping process.
The trend of peel off is highly erratic & random with no correlation with any critical stage.
What can be the root-cause of this?
How can we improve adhesion of Zinc plating with chromating on SS alloy?
Shubham Joshi
– Haryana, India
July 24, 2024
A. Hi Shubham.
Let’s start with these two questions please:
• Are you doing a Wood’s Nickel Strike ⇦ huh?, or any strike, before the zinc plating?
• Do you know what stainless steel alloy you are trying to plate onto?
Luck & Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com – Pine Beach, New Jersey
Need quick confidential answers? $25
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A. I hate to always be “that guy”, but another pertinent question here is why do this in the first place? Coatings like this are generally used for corrosion protection on carbon steel. There is no reason I can think of to pay extra for stainless steel and the corrosion protection inherent in its alloy composition, only to make that a moot point by covering that surface with a coating. Especially in the case of plating, given that plating stainless is more difficult than plating regular steel. (Plating stainless requires surface “activation”, which is the opposite of the passivity that stainless is intended to have.)
Ray Kremer
Stellar Solutions, Inc.
McHenry, Illinois
Q. Yes, the grade is ASTM A36.
It is something which is required for one of my customers exporting parts to Europe.
Keeping SS aside, what could be the possible reason for the same issue in MS metallurgy. We have already tried trials keeping the current density on the lower side but it has negatively impacted the adhesion.
Shubham Joshi [returning]
– Haryana, India
July 25, 2024
A. Hi again.
ASTM A36 is the MS grade, not the stainless steel. Poor adhesion in this rather different case is most often due to inadequate cleaning…
• Have you observed a waterbreak-free surface after the cleaning rinse and after the acid dip rinse?
• Have you tried scrubbing a few sample parts with a tampico brush
⇦ on
eBay or
Amazon [affil link] and a solution of pumice
⇦ on
eBay or
Amazon [affil link] before putting them into the process line?
I am trying to make this situation less abstract because I feel that it is the path towards progress, but you seem to be trying to keep it abstract 🙂
I don’t think “Keeping SS aside …” is an appropriate answer to “are you doing Wood’s nickel strike” and “what grade of SS?” 🙂.
Yes, it may be two different issues, but it may not be. If you’re doing proper pretreatment on the stainless and there is poor adhesion there as well, it could be something like silicones being used in the shop).
Luck & Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com – Pine Beach, New Jersey
Need quick confidential answers? $25
Need project assistance? $100/hr.
A. JOSHI,
Zinc plating peel off from plated part, Check the chemistry in zinc bath, Due to high zinc thickness on part. Do water break test, PART may not clean enough.
Popatbhai B. Patel
electroplating consultant – Roseville, Michigan