Take a look at "Corrosion Inhibitors" by CC Nathan and published by NACE International.
But the answer to your question is that the organic compounds that are used to inhibit acid corrosion on carbon steel were selected for that purpose. During the selection of these compounds for that application, the products may not have even been screened for potential use on SS. Therefore, it is not surprising that a commercial product that was intended for one application (steel) would not work when used for something else (SS).
There is also a potential issue when you consider what is being removed from the metal surface by the acid. If the "spent" acid now contains sulfides or ferric ions from the removal of FeS corrosion products or some form of oxide such as Fe2O3, then the acid may become even more aggressive to a SS by causing localized attack of the chrome oxide passive layer. This can lead to a form of galvanic corrosion where the exposed metal is corroding versus areas where the passive layer is still intact. This can result in even higher corrosion rates that on steel because you now have two forms of attack on the exposed area, the acid itself and the galvanic cell. Once again, the corrosion inhibitors were designed to reduce the corrosion rate of steel from VERY high levels so simply severe rates. They were not designed to help repassivate the SS. So in the case of the SS with galvanic issues, the inhibitor might help with one of the forms of corrosion, but not the other.
Hello
See the following book titles:
1-Corrosion Inhibitors, 2nd Edition: An Industrial Guide BY,Ernest W. Flick
2-Organic Inhibitors of Corrosion of Metals ,Author(s):Yurii I. Kuznetsov, A. D. Mercer, J. G. N. Thomas.
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