When selecting valves, the material of the valve body directly determines the product’s pressure-bearing capacity, service life, suitability for working conditions, and overall cost. Ductile iron undergoes spheroidization treatment so that the graphite inside is evenly distributed in a spherical shape, which compensates for the performance shortcomings of ordinary cast iron. It is the mainstream material choice for valve bodies in municipal water supply, building plumbing, hydraulic engineering, and other fields.

Ductile iron has a tensile strength of 400–600 MPa, close to that of ordinary carbon cast steel and far superior to traditional gray cast iron. This means the valve body has stronger load-bearing capacity, can withstand higher pressure and loads, and adapts well to medium- and low-pressure conditions as well as the load requirements of large-diameter valves, offering higher structural safety.

Picture 1Ductile Iron—A High-Strength, Versatile Casting Material

Spherical graphite structure endows the material with good toughness, which can buffer the pressure fluctuation of water supply system and the instantaneous stress impact caused by water hammer. It is not easy to occur brittle cracking, leakage and other problems, and improve the stability of the pipe network.

The ductile iron has a dense matrix, and its water corrosion resistance is superior to that of grey iron. With strong surface adhesion, it can be adapted to various anti-corrosion processes such as epoxy spraying to form a lasting anti-corrosion layer, adapt to clean water, reclaimed water, general industrial circulating water and other water environments, and extend the service life of the valve.

At the same time, the nodular cast iron has good casting flowability, and the complex valve body structure can be cast integrally, with high dimensional accuracy of finished products and less internal defects; Stable machining performance, easy to obtain high-precision sealing surface, ensuring the reliability of valve sealing, suitable for large-scale mass production.

Compared with the valve made of cast steel, the weight of ductile iron valve body of the same specification is 10% – 20% lighter, and the procurement cost is lower; Compared with the grey cast iron valve, the service life can be increased by 2-3 times, the operation and maintenance cost can be reduced, and the service life of the valve is longer.