What type of corrosion am I dealing with?
What type of corrosion am I dealing with?
(OP)
Here's some photos taken of a sample cut from a pipe which supplies cold process water to an ore preparation plant. The failure was detected when they observed a leak in the pipeline. Upon observing the photos you can see that there is obvious corrosion which probably led to the hole.
I am thinking that this is microbially influenced corrosion based on photos I've seen thus far but am not 100% sure. I don't know yet the conditions of the pipe (flow rate, temperature, pH) while it was in operation, so I can't provide you with that.
What type of corossion does this look like to you and what type of tests can I include in the scop of work to be done?
I appreciate your replies. I am still an inexperienced engineer and so I don't have too much experience analyzing failures.
I am thinking that this is microbially influenced corrosion based on photos I've seen thus far but am not 100% sure. I don't know yet the conditions of the pipe (flow rate, temperature, pH) while it was in operation, so I can't provide you with that.
What type of corossion does this look like to you and what type of tests can I include in the scop of work to be done?
I appreciate your replies. I am still an inexperienced engineer and so I don't have too much experience analyzing failures.





RE: What type of corrosion am I dealing with?
Need more information on operating conditions and water quality/type to decide. How many of these regions did you observe?
RE: What type of corrosion am I dealing with?
Can you get picture from a little further back to show some more of the pipe internal surface?
How long has the pipe been in service?
RE: What type of corrosion am I dealing with?
RE: What type of corrosion am I dealing with?
I tried to post more pics but I guess you can onlu post one at a time. Here's another shot.
RE: What type of corrosion am I dealing with?
If the pipe is horizontal and these corrosion pit locations are mostly along the bottom half of the run, this could be under deposit corrosion with no MIC.
RE: What type of corrosion am I dealing with?
It's kinda almost exactly in the middle side of of the horizontal pipe. Here's a pic of the pipe where the sample came from.
I'm assuing that the combination of the MIC and under deposit (probably from a biofilm) caused pitting corrosion which caused the hole in the pipe. Does this make sense?
RE: What type of corrosion am I dealing with?
Here is an outfit that sells tests kits for three primary culprits in MIC corrosion.
They also have some very good information in their library.
http://www.mic-test.com/slime
RE: What type of corrosion am I dealing with?
Steve Jones
Materials & Corrosion Engineer
http://www.linkedin.com/pub/8/83b/b04
RE: What type of corrosion am I dealing with?
There are plenty of other mechanisms that will result is similar corrosion damage, scaling is the most likely. Since this was at the mid-line of the pipe then the pipe have been half full for some time. You can get MIC, as well as scale formation and concentration of impurities along this interface.
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Plymouth Tube
RE: What type of corrosion am I dealing with?
V.
Corrosion & Rust Prevention Control
RE: What type of corrosion am I dealing with?
RE: What type of corrosion am I dealing with?
I've never seen MIC be very selective when it come to water I've seen and tested for and found MIC in all types of water, pure, aerated, deaerated, treated, etc, and under all conditions of PH and many temperatures. The only water that I haven't found MIC is water treated with hexavalent Chromium.
The only way to tell is by a specific test for one or all of the three bacteria.
Just remember that the red color that sometimes comes from the tap is iron bacteria supposedly good for you.
RE: What type of corrosion am I dealing with?
You guys provided some really good insight though and it is really appreciated. As more info is available, I will let you know of our findings.
RE: What type of corrosion am I dealing with?
If we can only retain 10% of the knowledge and information we are exposed to we will be way ahead of the game.
RE: What type of corrosion am I dealing with?
Steel pipe for water service is often specified cement etc. lined, to minimize internal tuberculation (and/or such "failure").
RE: What type of corrosion am I dealing with?
The samples are still being analyzed at a company and hopefully we will have their findings next week. I am sure we can't come to a 100% conclusion of the cause of failure yet but this info is a start.
RE: What type of corrosion am I dealing with?
RE: What type of corrosion am I dealing with?
RE: What type of corrosion am I dealing with?
RE: What type of corrosion am I dealing with?
RE: What type of corrosion am I dealing with?
You should red flag this post and start a new thread to ask a different question.
You will get a much better response than tacking it on an existing thread.
RE: What type of corrosion am I dealing with?
I also got the MIC diagnosis on a CuNi 90-10 piped heat exchanger, that cools hot air down with raw water from a nearby canal. The expert tells me there's little one can do. Killing the bacteria off with chlorine dosage is not allowed any more due to environmental regulations. The second best would be to periodically clean the inside of the pipes. From the material analysis it resulted that the chosen material CuNi seems to be less resistant against the organisms. He recommended us to step back to the former material Al-Brass. That seems to be able to form a better passivation layer that might ward off the attack. The problem could be avoided with titanium pipes.
The reason for my reaction is:
1. to share this experience with others
2. to find out if there are proven preventive measures other than using chemicals. I am also interested in proven cleaning methods. We apply hard plastic rotating brushes, but it is very hard to determine whether the biological slime is properly being removed by that.
Any other suggestions or tips ( pipe material ) are welcome!
Awaiting your reply,
Karel
RE: What type of corrosion am I dealing with?
Start a new thread!
RE: What type of corrosion am I dealing with?
The new thread has been created