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Re: Steel corrosion

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How do you know what the thickness was 50 years ago?  I don't have ASTM A6
in front of me, but I'd guess that the allowable variation in thickness
exceeds 0.01".

On the other hand, oxidation implies the addition of something.
__________________
John P. Riley, PE, SE
Riley Engineering


I just finished one of those jobs that remind you why you spent all that
time earning an education.  The only thing worse than foundry jobs: coal
bunker inspections!  Both were built around 1951.  The steel in one bunker
was never painted and is severely corroded (delaminated to less than 50% of
original cross section).  The other bunker was painted at one time and
herein lies the mystery.  The steel was cleaned as aggressively as possible
and then measured with a micrometer.  My measurements are showing the steel
in be an average of 0.01" thicker than it was 50 years ago.  The steel had a
pitted appearance, which I attribute to the paint.  My question is: can the
paint, in this type of environment, "fuse" with the steel?  What I mean is,
can it become indistinguishable after so many years of acidic exposure?

Could the extra material be the paint?

The steel was all solid in this bunker, so my interest is more out of
curiosity than concern.  I would appreciate any (readily available)
references or even anecdotal evidence from some of you crustier (I mean that
with respect) participants.

Thanks!
Jack Creviston, EIT


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