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world gathers for metal finishing
Q&As since 1989


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Saltwater staining and silver nitrate test

Q. Bundled steel pipes, covered in protective wrapping were carried on open trucks from factory to dockside, 72 miles over metaled and unmade roads. The dockside was unmade (i.e. pitted, muddy and with deep puddles). Rain was intermittently heavy over seven days' loading onto vessel. Loading was stopped during heaviest rain. The sea passage to discharge port was eight days'.

On discharge considerable rust staining was noticed on that wrapping that was intact. In part the wrapping had torn during passage. A proportion of the steel pipes were so badly rusted (about 25% of total) that they were not accepted by buyer. A silver nitrate [on eBay or Amazon] test was conducted three days' after unaccepted cargo had been discharged and stored in sheds at dockside.

The test revealed the presence of chlorides by vigorously producing a creamy foam. Not all damaged pipes tested positive for chlorides.

What does the test show? Can the test indicate the origin of the chlorides? In this circumstance, what else might the results of a silver nitrate test indicate?

John [last name deleted for privacy by Editor]
- London, Great Britain
2002

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Q. Dear Sirs,

Please certify the concentration of AgNO3 in ammonium solution for proper saltwater test on steel surface and corresponding contest of chlorides.

Regards,

Igor Sokolov
- St.Petersburg, Russia
2002

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Q. Can silver nitrate tests be accurate below 40 degrees F?

Matt Salkeld
Surveyor - New Orleans, Louisiana
2007