In our manufacturing process, we press a .1212/.1215 OD 303 SS insert into a .1207/.1210 ID SS body to a depth of .060 inches.  The problem we are having is leaking between the insert and body in excess of 0.2 SCCM. We realize that similar metals should not be used in this assembly, unfortunately this being a medical application changing material is slow and difficult.

We have tried press to a lessor depth and the leak has dropped.  Next, we're machining a counter-bore hole for alignment before the press fit section.

Any ideas for a permanent fix?Forged Steel Valves
First, as a new member I would like to say, thank-you all for your suggestions and support!  This is a great venue for true collaboration of ideas.  Second, I'm amazed at the quickness of responses I received about our problem.  This site is now a daily read.

Below is the result of an Engineering Symposium we had at work.   Let me know what you think.  One particular application for the part is the delivery of Nitric Oxide.

Different 300 Series
TBD possible material 17-4
Ream
Lubricant
Shorten length of insert depth
Cutting edge small ID of chamfer
MEMs
Machined in insert, EDM Lazier; Water Jet the hole
Plating
Welding
Heat/Freeze parts
Electro polish
Machine counter bore in body.
Usually stainless fittings are silver plated on the thread to avoid
galling. However I do not believe silver will be acceptable as
bio-compatible. Add to this that press-fit created stresses greater than
threading. I would try to completely gold plate the insert which is
quite small and the added price is minimal. The plate thickness is
usually 0.002mm thick and it may serve as a lubricant and it is
bio-compatible.

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