Quote:
Originally posted by Fishpart
Don't know everythign about SS, but it will corrode depending on the actual Alloy. In the 300 series the higher the number the more corrosion resitant the alloy is, 304 corrodes more quickly than 316 for example.
If moisture gets inside an encapsulated piece and can't get out it will probably corrode. Oxygen is the culprit that does the damage.....
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This is my field, maybe I can help.
Fishpart is right for the mostpart. However just cause a SS has a higher number does not make it better. Each grade is alloyed for specific reasons. 316 has molybdenum added which makes it more resistant to pitting damage than 304, but not general corrosion. 303 SS is real close to 304 in compositin, but is absolute crap, it is made for easy machining and suks for corrosion resistance. Another for instance,,,400 grades of SS are not good at corrosion resistance either, they are used in medical devices (scapels) and for SS cutters because they can be heat treated much harder than 300 types.
Biggest mistake an engineer made was building a swimming pool out of 304 "HEY IT WILL NEVER CORRODE!" Opps sorry, it cracks in the presence of stress and chloride (if it gets wet) Opps again its a swimming pool so there is agood chance it will be wet.
Anyway, alot depends on the environment. You are also correct that no oxygen=no corrosion. But plastics are not totally airtight. oxygen can and does migrate through plastics and rubbers (thats why balloons go flat). Another worry is the plastizers used in the manufacturing plastics, many contain chlorides (a no-no for SS) and other compounds which contain oxygen. So it is still possible to corrode, but any corrosion that way should stop after a short while, once the chemical are depleted.
But. why would you encapsulate SS anyway???
best off is leave it in the open, it forms its own protective layer in air.
Hope that helps a bit.
That will be 1500 $....please remit.....
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