Standard corrosion rate

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hi guys. do you have a valid standard about heat exchanger corrosion rate?

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3 Answers

  1. Dear Alireza, I suggest you to visit this link where you will probably be able to find the answers you are looking for and not only about the corrosion rate for heat exchangers: https://www.corrosionpedia.com/definition/337/corrosion-rate
    Obviously, the corrosion rate is always variable and first of all it depends on the kind of material used, its thickness, the temperatures and the fluids used, both on the shell side and inside the tubes themselves.

  2. A tank wall required a 5 mm wall thickness for mechanical considerations. The designer has determined that the corrosion rate will be 0.4 mm/yr and the expected life of the tank will be 10yr. The total corrosion allowance is the corrosion rate per year (0.4 mm x 10 yr = 4 mm).
    The corrosion allowance is doubled to 8 mm as a safety consideration.

     

    1 Comment

    1. What you report is a very empirical calculation and not applicable when it concerns the compliance with safety standards.
      In fact, the corrosion rate is not linear because it cannot consider the variables that will take place during the lifetime of the structure itself.

  3. Below are two tables with guidelines for corrosion allowance

     

    Corrosion allowance for steel pipes mm
    Superheated steam 0.3
    Saturated steam 0.8
    Steam coils in cargo tanks and liquid fuel tanks 2.0
    Feed water for boilers in open circuit systems 1.5
    Feed water for boilers in closed circuit systems 0.5
    Blow-down systems for boilers 1.5
    Compressed air 1.0
    Hydraulic oil 0.3
    Lubricating oil 0.3
    Fuel oil 1.0
    Thermal oil 1.0
    Fresh water 0.8
    Sea water 3.0
    Refrigerants referred to in Section 13 0.3
    Cargo systems for oil tankers 2.0
    Cargo systems for ships carrying liquefied gases 0.3

    Notes..

    • For pipes passing through tanks, an additional corrosion allowance is to be considered in order to account for the external corrosion.
    • Note 2.. The corrosion allowance of pipes efficiently protected against corrosion may be reduced by no more than 50%.
    • Note 3.. When the corrosion resistance of alloy steels is adequately demonstrated, the corrosion allowance may be disregarded.
     
    Corrosion allowance for non-ferrous metal pipes mm
    Copper 0,8
    Brass 0,8
    Copper-tin alloys 0,8
    Copper-nickel alloys with less than 10% of Ni 0,8
    Copper-nickel alloys with at least 10% of Ni 0,5
    Aluminium and aluminium alloys

    0,5

    1 Comment