•    What do you mean by small amount?
•    What kind of grades?
•    Who is the end user Market? Critical or nor Stainless Steel Nuclear or power part is different form basic part?
•    Is there any specification provided by your customers?

Stan
 

Food service or medical use involved?   

Hg has low solubility in SS, I can't find a ref offhand but I recall that it is <1ppm.
Surface contamination can be very large though.  Welding of surface contaminated SS will not only release a lot of Hg vapor (toxic) but will also likely suffer from LME cracking of welds.

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Plymouth Tube

I do not have a specific application in mind, but would be generally considering the effects of mercury contamination on a piping application where welding would be involved and the design would be to B31.3.  The grade would be 316 stainless.

If you don't have chemical mercury present, or a strong solution containing mercury as a process fluid in the system, it's hard for me to see where the (original) mercury contamination would start from.

In this case mercury free stainless steel is requested for the raw material, to make sure the material used for construction is not contaminated from the foundry.

Foundries can be a source of mercury contamination,when thermometers and other such equipments are mixed with the stainless steel scrap and melted. In normal industrial use this may not pose a threat,however in nuclear applications,if this contaminated  stainless finds its way through,it could be disastrous.It is felt that mercury can vaporize easily,and then later the mercury ions can cause damage if these vapors reach central core region of the reactor. Hence as an utmost precaution,mercury free stainless steel is recommended.

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"It's better to die standing than live your whole life on the knees" by Peter Mayle in his book A Good Year

Essentially all wrought stainless is refined in an AOD which totally removes mercury, lead, and other similar low-melting, high vapor-pressure metals. Any contamination would be on the surface and removable by cleaning.
Arunmrao is right about cast stainless and it could have contamination if it were only arc furnace or induction melted, without subsequent refining.

Michael McGuire
http://stainlesssteelforengineers.blogspot.com/