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The Reason For Pump Corrosion And Its Prevention

Pump Corrosion and Prevention

Pumps are an essential component for moving raw water, wastewater, mud, and sewage water through different processes. With increasing global demand for energy, the industry has been looking forward to pumping systems that maximize efficiency, reliability, and cost-effectiveness.

The pump efficiency can be reduced by three of these losses: Mechanical, Volumetric, and Hydraulic. Moving components are related to mechanical losses such as bearing and glands; Leakage of fluid is related to Volumetric loss such as discharge side of the pump to the suction side and frictional forces that are created between the fluid walls of hydraulic passage that quickens and changes the fluid direction is related to hydraulic loss.

The latest pump designs and coating methods improve the long-term performance of industrial pumps significantly. Users can increase production and lower operating costs by reducing the effects of corrosion and erosion. The development of better protective coating application procedures is keeping pace with ongoing study into the processes that decrease pump performance. A significant improvement can be made in the maintenance strategies by gaining a better understanding of the pumping process and factors that affect it.

What Is Pump Corrosion?

Corrosion or erosion causes wear on the pump, impeller, suction side plate, or nozzle. In general, pump wear or material loss can easily cause the pump to deviate from its BEP (best efficiency point) curves. Either can reduce the MTBF (mean time between failures) and make finding the true root cause difficult. What most of us don’t realize when dealing with these issues is that the whole cost of maintenance, production, and downtime can make the original pump cost appear extremely low. Erosion Corrosion is the result of a combination of erosion and corrosion occurring in the presence of a moving corrosive fluid or a metal component moving through the fluid, resulting in a rapid metal loss.

What causes Pump Corrosion?

When the mechanical effect of a fluid’s flow or velocity is combined with the fluid’s corrosive activity, the metal loss is accelerated. The mechanical removal of protective films is done in the initial stage and then the corrosion from the bare metal by a flowing corrosive takes place. Unless the tear of the component occurs, the process is cyclical. Corrosion-erosion is usually found around the tube blockage, in the ends of tube inlets or pump impellers.

When both corrosion and erosion are present in the operating conditions, the degradation of the mechanism can become very complex and depends upon the substrate and the chemistry of fluid. Oxide layers are created by corrosion on the low adherence, to the substrate that is prone to erosion. The passive layers can be damaged by erosion that leads to activation on the surface that quickens corrosion. Protection on surfaces is the core solution in this type of case.

What Is Pump Cavitation?

Cavitation is commonly seen on the pump impeller by a pressure difference. When the local pressure falls below the saturation level the fluid is being pumped, when there is a sudden pressure drop in the fluid, it causes the liquid to flash for vaporing. When the fluid flows, the vapor bubbles that are formed by the pressure drop are swept along the impeller vanes. The vapor bubbles rapidly collapse when they encounter a location where the local pressure is greater than saturation pressure, causing a shockwave that can cause considerable damage to the impeller and/or pump housing over time.

The reducing effect on pumping equipment cannot be enough, rather it is important to prevent cavitation. Some of these actions can prove it worth preventing:

  • The fluid temperature should be reduced.
  • The suction head should be increased
  • The Net Positive Suction Head Required (NPSHR) should be decreased

By the use of a bespoke coating system, the pump design should be reviewed or the causing damage should be minimized in the situations where the cavitations are unavoidable or the pumping system suffers from internal recirculation.

Impacts of Erosion and Corrosion on Your Pumping System

The pump’s mechanism can be degraded quickly if corrosion and erosion both are present in it. The overall efficiency of your pump system is affected if your pump goes under erosion or corrosion. By increasing the operational cost, it reduces your industrial output that leads to increased downtime for repair and maintenance.

1. Choose the Right Material for your pump

The right material for your pump helps to mitigate problems occurring due to corrosion and erosion. The corrosion rate to the maintenance cost is increased if you purchase cast iron or carbon steel pumps to reduce your overall cost. If you could handle the maintenance cost after including the corrosion rate, carbon steel or cast iron can be purchased. The presence of stagnant conditions is another major cause of erosion and corrosion in stainless steel pumps. Similarly, if the displaced fluid contains a high level of chlorine, it might corrode a stainless steel pump.

2. Protective Coating

The durability and performance of your industrial water pump can be improved by using advanced coating techniques. To reduce the effect of corrosion and erosion, coating such as Fusion Bonded Epoxy which is a polymeric coating can be applied to pump components. It also improves the hydraulic performance of the pumping process. Other corrosion-resistant coatings are carbide coatings that are tungsten along with nickel, cobalt, and chrome. Such customized coatings can meet the specific requirements of your applications.

3. Maintaining Legacy Equipment

The service life of a pump is extended by modern coating technology that has been applied to legacy equipment as a part of the refurbishment program. The performance and reliability of existing equipment can be improved significantly by implementing a new coating as a part of the refurbishment project. If a new pump design is required, it will not only improve the most appropriate base material but also will provide the best coating system for extended durability.


Any of the industrial processes maybe manufacturing, oil refineries, paper, wastewater treatment, or energy- requires pumps to operate it efficiently. Liquids need to be exerted at some point from the pumps, in all these processes. By boosting reliability and efficiency, you must minimize downtime and operational cost in your plant.

The biggest loss or known as the depreciation of these plants is by corrosion and erosion. Unlike domestic pumps, industrial pumps can be operated in rough environments and face continuous threats from erosion and corrosion. Did this article help with your pump problem? Visit us at Unnati Pumps for more information.