Which is the best material for the manufacture of pumps?

Which is the best material for the manufacture of pumps?

Cast Iron is recommended for a number of applications including manufacturing of a range of pumps like sump pumps and centrifugal pumps. Cast Iron has excellent mechanical and physical properties, which makes it a suitable candidate for manufacturing of pumps. For applications involving high temperature, a suitable metal is selected for manufacturing pumps depending upon three factors, nothing but the main advantages of cast iron as follows:

  • Corrosion resistance:
    When there is a steady increase in temperature, it makes the liquid to become more corrosive. Cast Iron is comparatively more corrosion resistant. Technically, cast iron is the preferred material for pumps that find applications in high temperatures.
  • Max. temperature limit:
    Sudden fluctuation in the temperature can cause tension in a material known as ‘thermal shock’. This can occur when hot oil is poured into a cold pump for start-up or cold water is sprayed on a hot pump when it’s cleaned. Cast iron pumps works satisfactorily under a temperature of 650 Degrees Fahrenheit. They can withstand the effects of thermal shock fairly well below this temperature. Ductile iron when subjected to heat can withstand failure up to a temperature of 800 Degrees Fahrenheit.

  • Coefficient of thermal expansion (CTE):
    The thermal expansion brings about certain dimensional changes in the pump’s external parts leading to functional failure of the pump. Changes in the dimensions could affect the interference fits and running clearances within the pump. Parts such as Head and Idler Pin, rotor bearing sleeve and Casing Bushings will lose their interference and move out of place causing failure and release of hot liquid in the spot. The CTE of cast iron is only 6.5 whereas steel and ductile iron has a CTE of 7.0. This makes cast iron the best possible candidate as a material for manufacturing pumps.

Malleable iron and ductile iron have good wear resistance, machinability, low notch sensitivity and vibration damping. They also possess increased ductility, toughness, durability, and moreover heat resistant too. Besides, cast iron pumps come with extra thick walls. It exhibits easy maintenance and repair when damages occur. With a pH of 6 or higher, Cast iron corrodes to produce a coating on its surface, which prevents the pump from corroding further.

Cast iron performs well in terms of casting, wear resistance and mobility compared to cast steel. Cast iron sumps are highly durable and give you higher ROI. Because a sump pump develops a high amount of heat, only cast iron sump can distribute the heat that is generated from the motor uniformly, thereby enhancing the pump’s life expectancy. Cast iron is built to endure high temperature, and therefore can resist internal shock well. It costs less in comparison with other types of metals and its parts can be made quickly. Also, the cast iron enhances the overall capacity of the motor pump.