Take a look at our white paper and tell us what you think (click here) : Surface Chemistry Improvement On 316L Stainless Steel Weld Zones With Gelled Citric Acid-Based Ultra Pass® System.
 Daryl L. Roll, P.E.As Astro Pak's Chief Technology Officer, Mr. Roll serves as the primary senior technical advisor for corrosion, surface chemistry and stainless steel passivation. With over 30 years of experience in chemical processing, Daryl has been published in MICRO, UltraPure Water Journal and Chemical Engineering for his papers on passivation and rouge control. He is a participant on the ASME BPE Subcommittees for Surface Finish and Materials of Construction requirements and a leading contributor for the Rouge and Passivation Task Groups. Mr. Roll holds a B.A. in Chemistry and Earth Science from the California State University of Fullerton and a Professional Engineer's license from the State of California. |
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April 10th, 2009 at 11:26 am
I can not find the white paper that is mentioned in your blog, I am really intereted in using this blog
please let me know where i can find this whit paper
Thank you
April 13th, 2009 at 12:13 pm
You can visit http://www.pharmaceuticalonline.com/download.mvc/Surface-Chemistry-Improvement-On-316L-Stainle-0002 to register with the magazine and download the paper. Thanks.
October 12th, 2011 at 7:58 am
Daryl,
We recently performed electropolishing of five mechanically polished vessels to mitigate a greyish black residue. Residue is gone, but when a riboflavin test was performed, the ribo formed a band about the circumference of the vessel and slowly migrated down the side wall (ribo was completely removed in 2.5 minutes).
We suspect that we are having wetting issues of the recently electropolished stainless surfaces and that the difficulting in wetting is causing cleaning issues. (Prior to EP, these vessels passed ribo with removal in 60 seconds, so the spray balls should be supplying adequate water to the surfaces). What can be done to allow these surfaces to clean? Thx
October 12th, 2011 at 12:29 pm
Gary:
EP makes the surface much more cleanable and should not have caused any negative distruption to the surface. If the surface has been properly cleaned and no residue is present on the surface, then I would call the EP contractor to inspect the surface for an upset or groove in the surface that is holding the riboflavin dye in place. It may require polishing to smooth out the line or groove/upset and re-EP to remove the change in surface profile. A smooth, clean EP surface should sheet water completely and not form spots or droplets or lines of fluid accumulation. A surface like you describe should pass riboflavin testing easily.
Hope this is helpful, Doc.