Erosion corrosion wet steam

Carbon steel is generally non resistent to erosion corrosion: pH value, steam-water ratio, local flow rate and chemical composition of steel are important.
Suspended iron oxides in steam-water circuits may cause trouble in both conventional and nuclear power stations. This happens rather often; e.g., corrosion in conventional boiler evaporators, corrosion in PWR steam generators and deposition of iron oxides on fuel elements in nuclear reactors.

BWR bocht
A pipe behind the BWR water separator was constructed by welding bent steel plates. One of those plates had been attacked severely.

In view of these problems, it is recommended that the iron content in steam water circuits be kept as low as possible. This iron comes from erosion-corrosion, the major sources of which are water separators, wet steam pipes, preheaters, and evaporators.
Erosion-corrosion depends on water chemistry, water velocity, and chemical composition of the steel.

The research at KEMA focused on the relationship between the chemical composition of steel and erosioncorrosion resistance. This relation-ship has been neglected in the past because water chemistry and velocity were thought to be the dominant factors.

See for the results of the studie the following papers:
65, 60, 47, 46, 45, 27, 21 and 17.

 

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