Impingement corrosion (Topic 11022)

Impingement corrosion can occur for example in bends if the liquid contains gas bubbles or solids, or if a gas flow contains droplets. The droplets or bubbles will hammer against the metal surface and can cause rapid failure if the conditions are unfavourable, see figure below.

Impingement in a bend, arrows show the direction of the main flow.

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If there is a risk for bubbles or droplets in the flow, it is very important that the flow rate is kept low and bends are made smooth and not as sharp 90ƒ angles. It is also desirable to separate out solids, water or gas early in a flow system in order to avoid two phase flow.