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You could find Corrosion Allowance Calculator and many other wonderful things.corrosion allowances

Thank you

But I want to know the method of caculation basically.

I have faced two corrosion allowance for two part of a pipe line. The chemical composition of fluor and the material of pipe is same!

I'm sorry, I don't believe you grasp the concept of "corrosion allowance".

The method of calculating the amount of material loss due to surface erosion is dependent on the materials involved, and is different in each case. The math is relatively simple once you understand this.

Corrosion allowances for most common materials are well known and only involve simple math to get results.

Don't try to re-invent the wheel.

Thank you for attention

If I had enough experience to corrosion, I would never write the question and never help this site!

In our company, all of pipline is carbon steel but variety fluor flows in it from acids to bases. According to kind of fluor, corrosion allowance is determined. So, I get a result that corrosion rate determin corrosion allowance. But I face to a case which get me scruple. What is the reason two corrosion allowance for one corrosion rate?

Please guide me.

There are loads of materials compatibility databases on the web, Uncle. It may be that you are using a meterial that is totally incompatible with the fluids you are handling. For example, no-one would give a corrosion allowance for sulphuric acid in PVDF piping, because no corrosion takes place.

According to the compatibility chart Cole Parmer. CS is not recommended for this service

Fluorine is the chemical element with atomic number 9, represented by the symbol F. It is the lightest element of the halogen column of the periodic table and has a single stable isotope, fluorine-19. At standard pressure and temperature, fluorine is a pale yellow gas composed of diatomic molecules, F₂. In stars, fluorine is rare compared to other light elements. In Earth's crust, fluorine is very common, being the thirteenth most abundant element.

WP

Corrosion allowance is a company preference basically. It can vary from 0" to any thickness.

Basically, you calculate the required thickness and then pick a life expectancy. If you want to replace the pipe or vessel every 6 months that's your choice.

Get a corrosion handbook if you don't have expected corrosion rates and use that to predict the initial corrosion rate. Then follow whichever inspection code that applies (API 510, API 570, API 653, etc.).

And yes you can use carbon steel for acids and bases. It's actually better to use for some fluids than more corrosion resistant materials like stainless steel.

Thank you cingold

you understand my question exactlly. Thank you so much.

But we don't have any hand book or corrosion rate.

Can you help me more? Do you have any document about corrosion rate?

Unfortunately no. I don't remember what book we used at my last job to get corrosion rates. It was either the Metals Handbook or the Corrosion Handbook.

You could also contact NACE. I believe all of these options will cost money to get an answer but they should save money in the long run.