Pickling & Passivating 410S stainless steel per ASTM A380?

A. Hi John. 410S is used for petrochemical refining and things like that because it remains ductile instead of hardening when heated or welded. But apparently this is rather simply achieved by holding the carbon content very low and possibly adding very tiny amounts of titanium or other materials. 4xx stainless is always somewhat more difficult to passivate than 3XX, but I see no obvious reason 410S can't be conventionally etched and passivated; and since electropolished 410S can be purchased, that obviously is a do-able process.

As for Hem profiles, I didn't know what they were, but found this excerpt from incafe2000.com ...

... which cleared it all up :-)

Yes, surely there are surely companies in Europe who provide the service since 410S doesn't seem special from a wet finishing perspective. Sorry we can't post brands & sources except clearly labeled advertisements (huh? why?)

Luck & Regards,

adv.

Hi John,
Please contact Nicola Budelli from BAMA in Turbigo, Italy. They acquired our technologies for passivation, electropolishing of 400 series ss long ago. For such large piece they can do gel etching or partial electropolishing. Their tank size may also incorporate the whole piece too. Nicola will definitely help you.

? Sakthivel,
Please describe the exact process you are using, including all chemicals, rinses, and times involved. Please describe at what point in the sequence the discoloration first appears. Please provide photographs if possible.

Also, you say "clad", does that mean it is another material with a thin sheet of 410 stainless covering it? What is the base material, carbon steel or something else?

A. Ashish,
You can certainly pickle and/or passivate 410SS, though you would have to be absolutely certain that none of the chemistry will be contacting the carbon steel, or else it will start to destroy it. Acid solutions for pickling and passivating are given in A380 and ASTM A967.

Otherwise, mechanical descaling is always a viable alternative to pickling, but for corrosion resistance it's harder to beat a good passivation treatment.

A. Yes, It can be successfully picked and passivized. The paste must be alternated to be suitable for 400 series stainless steel.

A. Imran,
I'm not sure what you mean. There is nothing in A380 that says anything against pickling or passivating 410 stainless. Can you explain the nature of this sweat contamination a little more? Do you have some kind of scale or discoloration that is against the appearance you want, or is this a rusting issue? What size are the trays, are you able to dip them in a bath for treatment?