Standard Corrosion Rates 1

[wajahat]

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;---URGENT----<br>Is there anything like standard acceptable corrosion rates. How would a corrosion rate yielded from a standard corrosion monitoring test like 'corrosion coupons' be considered either acceptable or un-acceptable<br><br>I am to install corrosion coupons at our Ammonia and Urea plant cooling water systems. Can anyone help me in this regard?<br><br>Wajahat Abbas<br>Inspection Section<br>FFC Jordan Fertilizer Company

 

[HScribner]

NACE Pamphlet RP 0775-91 Preparation and Installation of Corrosion Coupons and Interpretation of Test Data in Oilfield Operations is a pretty general rule.&nbsp;&nbsp;You can contact me at 215-283-7776 and I will direct you to more info, or use <A HREF="

http://www.NACE.org"

TARGET="_new">

http://www.NACE.org</A>

(?) and find out directly from the National Association of Corrosion Engineers.

 

Detail chemistry of corrosion phenomena and its control in urea synthesis???

 

[rustbuster1]

In general, the acceptability of any specific corrosion rate depends on the design or expected life of the corroding part.
Most standard corrosion tables consider corrosion rates lower than 20 mils per year (0.5 mmpy) &quot;acceptable&quot; on the premise that most corroding components have been designed with a logical corrosion allowance that will provide the desired service life. However, in the pharmaceutical or food business the acceptable rate may be very much lower because of tainting/contamination of the product.

If you put corrosion coupons in cooling water stream you should have a purpose - evaluating the effects of water chemistry changes on the materials of construction, or trying to define the corrosion conditions so that life prediction can be made, or determining the corrosion in the worst locations so inspection frequencies can be devised, etc. It is essential to match the materials properly - nothing is learned about copper tubes from carbon steel coupons, and so on.

When you know the purpose, come back on here and see if the test you're planning makes sense.

One test is worth a thousand opinions, but only if the test makes sense in the first place!!

 

[PTCollins]

I was just wondering if anyone has a complete data set for the target mass loss for the coupons in GM9540P. The table is incomplete and calculating the target losses from the end of test mass loss seems a bit confusing to me. If anyone has any info or any tips on figuring out my little dilemma, it would be much appreciated to hear from you!

Thanks,
Paul T. Collins
Laboratory Technician/MIS