Re: Titanium - Crevice Corrosion

Dave Herbal <[EMAIL PROTECTED]> wrote in message news:<[EMAIL PROTECTED]>...
> I have a Grade 2 Ti tube (2mm wall) which has been lying in a stainless tank
> containing hot orthophosphoric acid.
> The contacting face of the tube now exhibits a line of perfectly round pits.
> As Ti is pretty resistant to pitting, crevice and galvanic corrosion, does
> anyone have any ideas why this had occurred?

Dave:

It sounds like crevice corrosion.  Whether you should have significant
corrosion or not depends on some details like the acid concentration
and temperature, neither of which you stated.

Timet has some isocorrosion data (5mpy) that you can look up. Go to
www.timet.com/coresistframe.html and download the book in pdf format.
Look on page 20 of the Acrobat file for Figure 12.  You'd expect 5 mpy
for 30% acid at room temperature.

 
Pittsburgh Pete  


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