Rate of corrosion

[ruby]

Hai, I have just registered myself with this site. I would like to know the corrosion rate of carbon steel in the seawater surrounding condition, especially for the storage tanks which were built along the seawater side. The material used is A537 CL2 for the shells and A285-C for the roof and the bottom. Please answer the question with some relevant data regarding the rate of corrosion and the rate of penetration.

Thankyou

 

[Mopar]

The corrosion effects on mild steel have many variables when introduced to sea water. Temperature will play a factor, the warmer the water the quicker the corrosion process. There is only one way to stop this action. Have the steel sandblasted and painted with proper underwater coatings, this coating should be surveyed every 12 months.
Jess

 

[TTT]

Hi Ruby
do you have existing corrosion, or corrosion under the floor?

 

[pickuw]

Hi
Usually the corrosion allowance for carbon steels is widely taken as 1.27mm. (Refer to any process plants designers pipe standards like Haldor Topsoe, Chiyoda, etc.) Take the life expextancy of equipment as 50 years. From these two values you arrive at an acceptable rate of 5mpy (Mils per year). This is a safe figure for most of carbon steel applications. ssp
pic, kuw.

 

[chlee1]

You may setup an electrochemistry cell and store your sample at the designated env for hours, monitor the electro potential change to time, while altering parameters like acidity, concentration, temp

plot a polarisation graph, this will give you a fast and brief results of the corrosion rate estimation.