Calculation of Rp and Icorr Based on Cycle Usage

We still don't do homework.

Try: www.icorr.org

You will need to buy oranges for 20 years, it is healthy.

Hey! I thought we were talking apples, and here you go bringing up oranges.

The cycle usage of what exactly?

The cycle usage of a carbon steel pressure vessel (autoclave) used for the vulcanization of rubber.

Assuming a 20 year life, cycle usage of 24 hrs for 5 days per week operating for 40 weeks per year.

I have calculated corrosion rate, which is: 4.87 µA/cm² = 0.0565 mm/y thickness loss.

Now how do i tie it in with the above mentioned cycle usage? Do i need to account for 20 years or should i count for cycle usage, which is to be: (24*5)*40=4800 hrs in 1 year*20 years=96,000 hrs in 20 years. which is 10 years of operation, so 0.0565 mm/y*10=0.62 mm loss in 20 years of operation.

Am i right??? Thanks!

Now that you did all the calculations, and your apples and oranges are sorted out, do you think that you might need to actually monitor corrosion with a corrosion monitor?

Sometimes even the best calculations do not cover all the conditions that could occur locally in such a vessel...but then neither will a corrosion probe that is sitting somewhere in the vessel, when the problem is on the other side of the vessel.

This is the sort of topic that needs to be discussed with the Engineer/Surveyor from the company providing burst indemnity insurance cover on the vessel. That dialogue is important, for it establishes the validity of the calculations for insurance cover purposes, the robustness of the design, the written scheme of examination and the routine inspection frequency once the vessel has been brought into use. Open that dialogue now/this morning/today/immediately, if not sooner.