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Best way to remove the blue or yellowish heat discoloration marks from spot welding the stainless steel

Our company sometimes welds together type 316 stainless steel metal enclosures. When the customer does not want the finished product painted, what is the best way to remove the blue or yellowish heat discoloration marks from spot welding the stainless steel. If we try sanding or buffing then we have to sand the unit all over to make the finish uniform. Is there an easier chemical or other way to remove these spot welding marks ?

Dave Smith
Engineering Manager at Industrial Fabrication Shop - Beaver, West Virginia, USA
2007

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Hi,

Have you tried pickling paste?

Micheline Forth
- Rincon, Georgia, USA
2007

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First of two simultaneous responses --

Do a search for passivating and/or pickling paste. It will remove the heat color.

Jeffrey Holmes, CEF
Spartanburg, South Carolina
2007

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Second of two simultaneous responses --

I may sound dumb here, but I just recently read of a new process that uses, I think it said, ultrasound to remove weld discoloration. I also think there are a couple of new developments in the chemical industry. I suggest you search recent trade publications over the past 6 months.

AF Kenton
retired business owner - Hatboro, Pennsylvania
2007

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Dave,
As an alternative to pure chemical (pickle paste) and abrasive/blasting methods, you can use an electric current to remove weld discoloration. The process is sort of a localized electropolish. Let us know if we can help.

Ray Kremer
Stellar Solutions, Inc.

McHenry, Illinois

2007