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Weldability (Resistance Welding) of passivated parts

2003

Ours is a automobile company. We are using zinc plated (galvanized) parts which are resistance welded to manufacture body shell.

Recently our design department has introduced yellow passivated parts instead of galvanized parts for trial batch.

We have welded (resistance welding) very small batch of passivated parts without much problems. If in future we go for higher volumes, are we likely to face any major problem in terms of quality of welding.

We faced lot of problems in the past while welding galvanized parts. Now shifting from galvanized parts to passivated parts our problem will be minimized or aggravated?

Please comment about the weldability of zinc plated parts & yellow passivated parts. We imagine that it will be more difficult to weld passivated parts & will create tip sticking problem, weak spots, frequent adjustment in welding parameters, higher cycle time etc. Kindly advise.

Thank you,

Patil SS
- Pune, Maharashtra, India

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Hi, Patil. As Wilfred Brimley says to Robert Redford in 'The Natural': You're tryin' to break into this game at an age when you should be hanging up their spikes.

Yellow passivation (hexavalent chromate) is already forbidden in Europe and is very rapidly being completely phased out of automobiles around the world. Your design department certainly doesn't want to introduce this. Trivalent chromate is probably a possibility. Good luck

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2003