Corrosion

Corrosion is caused by a chemical or electrochemical attack on the surface of the metals. It is increased when dierc is an increase in temperature and/or presence of oxygen in the fluid or the surface of the fluid.

We can aggravate the corrosion effect if misaligned parts have relative movement, such as loose fit bearings or rapid changes in the system. Cavitation, erosion and high fluid velocity advance the corrosion process.

Cast Iron is a widely used material for centrifugal pump housings. It is used when the fluid PH is 6 or higher (not acid). Cast Iron corrodes and forms a protective coating on die surface of die metal. This graphitized surface protects the metal from further corrosion as long as the coating is intact. High velocity fluids, cavitation, metal to metal contact and erosion can affect this protective coating.

If corrosion exists, the pump-wet parts can be changed for other materials such as stainless steel or composite material. Impellers can be replaced by bronze cast impellers or other materials.

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