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Discussion Forums - The Hendrix Group
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12/6/2004 9:00 AM
 
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patel 
We are manufacturing SS 304L components. After tumbling in Alox we are pickling them in HF HNO3 soln in a SS 316 barrel. After this we are using caustic soln to clean the compnents( PH 9.4 of caustic). Finally we passivate them in Citrisurf ( Stellar ) . However in 5% NACl some of the components fail with corrossion developing. There are some minor pits on the compnents which are caused due to pickling. Can you suggest where we are going wrong and why this corrossion is happening?
 
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12/8/2004 9:00 AM
 
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patel: We are not sure from your post whether the 304SS components are pitting in 5% NACL or the pickling/passivating solution. If pitting in the pickling solution, several things could cause this, including too high a temperature, too long a soak or a contaminated pickling solution. Look at your pickling parameters. If pitting in a 5% NACL solution, we are not surprised. Hope this helps! David Hendrix The Hendrix Group Inc.
 
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12/22/2004 9:00 AM
 
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304L is not totally resistant to NaCl solution, and definitely not resistant to long term salt spray by the ocean. Sounds like one possibility based on the small number of failures is that you have some inclusions, or even possibly some pitting starting in the pickling solutions.
 
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